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Alessandro ULRICI

Professore Associato
Dipartimento di Scienze della Vita sede ex-Agraria


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Pubblicazioni

2021 - Analysis of housing risk factors for the welfare of lean and heavy pigs in a sample of european fattening farms [Articolo su rivista]
Ferrari, P.; Ulrici, A.; Barbari, M.
abstract

Pig welfare is affected by housing conditions, the minimum requirements of which are set up by EU legislation. Animal and non-animal-based measures are useful indicators to investigate housing risk factors for pig welfare. An observational study on 51 pig farms in seven EU countries, aimed at investigating housing risk factors for the welfare of finishing pigs, showed body weight and presence of bedded solid floored resting area (BED) identifying three clusters of farms. Farms with BED were featured by no or limited tail docking, larger availability of manipulable materials and lower number of pigs per farm and per annual work unit. In these farms, less skin and ear lesions were found, compared with lean pigs of farms without BED, which were characterized by lower pig space allowance, mortality rate and medication cost. In farms without BED, heavy pigs were featured by more space per pig, more pigs per drinker and higher mortality rate and medication cost per pig, compared to lean pigs. No statistical difference in tail lesions was found between the three farm clusters, although tail docking was performed in all farms without BED and not performed on most farms with BED.


2021 - Evaluation of the effect of factors related to preparation and composition of grated Parmigiano Reggiano cheese using NIR hyperspectral imaging [Articolo su rivista]
Calvini, R.; Michelini, S.; Pizzamiglio, V.; Foca, G.; Ulrici, A.
abstract

The present study is focused on the evaluation of the effect of grater type and fat content of the pulp on the spectral response obtained by near infrared hyperspectral imaging (NIR-HSI), when this technique is used to determine the rind percentage in Parmigiano Reggiano (P-R) cheese. To this aim, grated P-R cheese samples were prepared considering all the possible combinations between three levels of rind amount (8%, 18% and 28%), two levels of fat content of the pulp and two different grater types, and the corresponding hyperspectral images were acquired in the 900–1700 nm spectral range. In a first step, the average spectrum (AS) was calculated from each hyperspectral image, and the corresponding dataset was analysed by means of Analysis of Variance Simultaneous Component Analysis (ASCA) to assess the effect of the three considered factors and their two-way interactions on the spectral response. Then, the hyperspectral images were converted into Common Space Hyperspectrograms (CSH), which are signals obtained by merging in sequence the frequency distribution curves of quantities calculated from a Principal Component Analysis (PCA) model common to the whole hyperspectral image dataset. ASCA was also applied to the CSH dataset, in order to evaluate the effect of the considered factors on this kind of signals. Generally, all the three factors resulted to have a significant effect, but with a different extent according to the method used to analyse the hyperspectral images. Indeed, while fat content of the pulp and rind percentage showed a comparable effect on the spectral response of AS dataset, in the case of CSH signals rind percentage had a greater effect compared to the other main factors. However, CSH were also more sensitive to differences ascribable to the natural variability between diverse Parmigiano Reggiano cheese samples.


2021 - Multivariate Analysis in Microbiome Description: Correlation of Human Gut Protein Degraders, Metabolites, and Predicted Metabolic Functions [Articolo su rivista]
Raimondi, S.; Calvini, R.; Candeliere, F.; Leonardi, A.; Ulrici, A.; Rossi, M.; Amaretti, A.
abstract

Protein catabolism by intestinal bacteria is infamous for releasing many harmful compounds, negatively affecting the health status, both locally and systemically. In a previous study, we enriched in protein degraders the fecal microbiota of five subjects, utilizing a medium containing protein and peptides as sole fermentable substrates and we monitored their evolution by 16S rRNA gene profiling. In the present study, we fused the microbiome data and the data obtained by the analysis of the volatile organic compounds (VOCs) in the headspace of the cultures. Then, we utilized ANOVA simultaneous component analysis (ASCA) to establish a relationship between metabolites and bacteria. In particular, ASCA allowed to separately assess the effect of subject, time, inoculum concentration, and their binary interactions on both microbiome and volatilome data. All the ASCA submodels pointed out a consistent association between indole and Escherichia–Shigella, and the relationship of butyric, 3-methyl butanoic, and benzenepropanoic acids with some bacterial taxa that were major determinants of cultures at 6 h, such as Lachnoclostridiaceae (Lachnoclostridium), Clostridiaceae (Clostridium sensu stricto), and Sutterellaceae (Sutterella and Parasutterella). The metagenome reconstruction with PICRUSt2 and its functional annotation indicated that enrichment in a protein-based medium affected the richness and diversity of functional profiles, in the face of a decrease of richness and evenness of the microbial community. Linear discriminant analysis (LDA) effect size indicated a positive differential abundance (p < 0.05) for the modules of amino acid catabolism that may be at the basis of the changes of VOC profile. In particular, predicted genes encoding functions belonging to the superpathways of ornithine, arginine, and putrescine transformation to GABA and eventually to succinyl-CoA, of methionine degradation, and various routes of breakdown of aromatic compounds yielding succinyl-CoA or acetyl-CoA became significantly more abundant in the metagenome of the bacterial community.


2021 - Multivariate exploratory data analysis by PCA of the combined effect of film-forming composition, drying conditions, and UV-C irradiation on the functional properties of films based on chitosan and pectin [Articolo su rivista]
Bigi, F.; Haghighi, H.; De Leo, R.; Ulrici, A.; Pulvirenti, A.
abstract

The technical features of biodegradable films depend on several manufacturing parameters. Exploiting these films on an industrial basis requires statistical models for the fast and effective evaluation of these parameters. This study analyses the impact of compositional and drying factors on the microstructural and functional properties of films based on chitosan and pectin through a multivariate approach. A total of 32 formulations were developed and the results were analysed through principal component analysis (PCA). Four formulations did not form films due to the photodegradation caused by prolonged UV-C irradiation. Films containing glycerol had a higher elasticity (1.5–39%) than those with propylene glycol or that were not plasticized (1.2–12%). Glycerol increased the thickness of pectin films (56–77 μm). Sodium trimethaphosphate (STMP) enhanced the UV mean absorbance of both pectin and chitosan films (0.7–1.7). In addition, STMP led to an increase of thickness (72–129 μm) and air permeability (38.6 × 103 to 9206.1 × 103 cm3/m2 × day × kPa) of the chitosan films, while CaCl2 led to a decrease of thickness (31–59 μm) and air permeability (23.9 × 103 to 46.8 × 103 cm3/m2 × day × kPa) of the pectin films.


2021 - Simultaneous Detection of Glucose and Fructose in Synthetic Musts by Multivariate Analysis of Silica-Based Amperometric Sensor Signals [Articolo su rivista]
Crespo-Rosa, Joaquin Rafael; Foca, Giorgia; Ulrici, Alessandro; Pigani, Laura; Zanfrognini, Barbara; Cubillana-Aguilera, Laura; Palacios-Santander, José María; Zanardi, Chiara
abstract

Silica-based electrodes which permanently include a graphite/Au nanoparticles composite were tested for non-enzymatic detection of glucose and fructose. The composite material showed an effective electrocatalytic activity, to achieve the oxidation of the two analytes at quite low potential values and with good linearity. Reduced surface passivation was observed even in presence of organic species normally constituting real samples. Electrochemical responses were systematically recorded in cyclic voltammetry and differential pulse voltammetry by analysing 99 solutions containing glucose and fructose at different concentration values. The analysed samples consisted both in glucose and fructose aqueous solutions at pH 12 and in solutions of synthetic musts of red grapes, to test the feasibility of the approach in a real frame. Multivariate exploratory analyses of the electrochemical signals were performed using the Principal Component Analysis (PCA). This gave evidence of the effectiveness of the chemometric approach to study the electrochemical sensor responses. Thanks to PCA, it was possible to highlight the different contributions of glucose and fructose to the voltammetric signal, allowing their selective determination.


2021 - Stink bug study reveals Gold3 preference [Articolo su rivista]
Preti, M.; Moretti, C.; Landi, M.; Bombardini, E.; Tommasini, M. G.; Foca, G.; Ulrici, A.; Maistrello, L.
abstract

An Italian study of feeding damage by brown marmorated stink bug found major damage in the month before harvest in Gold3, when high fruit-drop occurred. Injured Hayward had much lower fruit drop and there were no differences in post harvest storage performance between injured and non-injured fruit.


2021 - Tracing geographical origin of Lambrusco PDO wines using isotope ratios of oxygen, boron, strontium, lead and their elemental concentration [Articolo su rivista]
Lancellotti, L.; Sighinolfi, S.; Ulrici, A.; Maletti, L.; Durante, C.; Marchetti, A.; Tassi, L.
abstract

Wine identification is one of the most important aspects in the classification of wines and consumer protection. In particular, assuring wine authenticity is a crucial issue on which researchers are focusing on. This study aims to evaluate the feasibility of using chemical (B, Pb and Sr concentration) and isotopic compositions (δ11B, 20yPb/20xPb, 87Sr/86Sr and δ18O) of wine samples to trace their geographic origins. Different PDO Lambrusco wines coming from a confined area of northern Italy were analyzed and all the isotopic systematics were monitored by using a multi collector inductively coupled plasma mass spectrometer (MC-ICP/MS). The obtained results showed that boron isotope ratio measurements led to a satisfactory degree of accuracy and precision (measured value, n = 28, 11B/10B of NIST SRM 951a equal to 4.04343 ± 0.00178, (u = 2s) with a certified value of 4.04362 ± 0.00136 (u = 2s). Furthermore, in the present study, it has been possible to highlight significant differences among samples by means of one-way analysis of variance (ANOVA) and post hoc Tukey-Kramer test. Finally, Principal Component Analysis (PCA) was also carried out in order to evaluate to which extent the different PDOs can be distinguished from each other, taking into account the whole set of geographical origin descriptors. Although δ11B provided more sensitive information, the obtained results highlighted the important to consider the synergistic combination of all the investigated parameters to trace the different samples and the need to combine the obtained values with the same parameters evaluated in the soil, water and fertilizer as well.


2020 - Chemical Characterization Of Commercial Balsamic Vinegar Glaze [Articolo su rivista]
Lancellotti, L.; Ulrici, A.; Sighinolfi, S.; Marchetti, A.
abstract

The present study reports the chemical characterization of commercial balsamic vinegar glaze (BVG), a side product of the world-famous Aceto Balsamico di Modena (ABM). BVG, originally a homemade sweet and sour sauce, is now produced on an industrial scale and is gaining a growing success. The determination of total titratable acidity, dry matter, ash, metals, sugars, phenolic acids and furfurals is reported for BVG samples of different batches and years of production. Principal component analysis (PCA) and ANOVA test were applied to evaluate the experimental data. The results showed that the chemical characteristics of the product are almost unchanged in the investigated years and well reflect the characteristics of the ABM. Moreover, it was found that potentially harmful species, namely furfural compounds and heavy metals, were at a lower concentration than that of homologous products. In particular, the concentration of heavy metals, such as Cu, Zn and Pb, suggests that a preventive demetallization of the BVG starting raw materials occurs.


2020 - Colourgrams GUI: A graphical user-friendly interface for the analysis of large datasets of RGB images [Articolo su rivista]
Calvini, R.; Orlandi, G.; Foca, G.; Ulrici, A.
abstract

Colourgrams GUI is a graphical user-friendly interface developed in order to facilitate the analysis of large datasets of RGB images through the colourgrams approach. Briefly, the colourgrams approach consists in converting a dataset of RGB images into a matrix of one-dimensional signals, the colourgrams, each one codifying the colour content of the corresponding original image. This matrix of signals can be in turn analysed by means of common multivariate statistical methods, such as Principal Component Analysis (PCA) for exploratory analysis of the image dataset, or Partial Least Squares (PLS) regression for the quantification of colour-related properties of interest. Colourgrams GUI allows to easily convert the dataset of RGB images into the colourgrams matrix, to interactively visualize the signals coloured according to qualitative and/or quantitative properties of the corresponding samples and to visualize the colour features corresponding to selected colourgram regions into the image domain. In addition, the software also allows to analyse the colourgrams matrix by means of PCA and PLS.


2020 - Dual Stage Image Analysis for a complex pattern classification task: Ham veining defect detection [Articolo su rivista]
Lopes, J. F.; Barbon, A. P. A. C.; Orlandi, G.; Calvini, R.; Lo Fiego, D. P.; Ulrici, A.; Barbon, S.
abstract

Veins in pork thigh carcass are directly related to the quality of dry-cured ham, and consequently to its market value. Some veining defects over the surface of raw ham are easily detected by humans and precisely assessed by a specialist. However, the automatic evaluation of raw ham quality by image analysis poses some challenges to the traditional Computer Vision Systems (CVS), many of them grounded on the complex image pattern related to each defect level. To improve the CVS classification performance without overburdening feature extraction, as well as the common machine learning modelling, we propose Dual Stage Image Analysis (DSIA). DSIA is an additional step in a CVS, that was built in two stages based on the “divide and conquer” strategy. The first stage consists of splitting the region of interest into sub-regions to predict the presence of veining. In the second stage, the algorithm computes the number of veining sub-regions to assess the final defect level classification. A total of 194 raw ham samples were used to evaluate the DSIA performance in the experiments. Support Vector Machine and Random Forest algorithms were compared for inducing the classification model using 92 image features. Random Forest model was the best, capable of predicting defect level with 88.10% accuracy using DSIA. Without DSIA, the CVS with RF achieved an accuracy of 63.10%.


2020 - Exploring the potential of NIR hyperspectral imaging for automated quantification of rind amount in grated Parmigiano Reggiano cheese [Articolo su rivista]
Calvini, R.; Michelini, S.; Pizzamiglio, V.; Foca, G.; Ulrici, A.
abstract

Parmigiano Reggiano (P-R) is one of the most important Italian food products labelled with Protected Designation of Origin (PDO). The PDO denomination is applied also to grated P-R cheese products meeting the requirements regulated by the Specifications of Parmigiano Reggiano Cheese. Different quality parameters are monitored, including the percentage of rind, which is edible and should not exceed the limit of 18% (w/w). The present study aims at evaluating the possibility of using near infrared hyperspectral imaging (NIR-HSI) to quantify the rind percentage in grated Parmigiano Reggiano cheese samples in a fast and non-destructive manner. Indeed, NIR-HSI allows the simultaneous acquisition of both spatial and spectral information from a sample, which is more suitable than classical single-point spectroscopy for the analysis of heterogeneous samples like grated cheese. Hyperspectral images of grated P-R cheese samples containing increasing levels of rind were acquired in the 900–1700 nm spectral range. Each hyperspectral image was firstly converted into a one-dimensional signal, named hyperspectrogram, which codifies the relevant information contained in the image. Then, the matrix of hyperspectrograms was used to calculate a calibration model for the prediction of the rind percentage using Partial Least Squares (PLS) regression. The calibration model was validated considering two external test sets of samples, confirming the effectiveness of the proposed approach.


2020 - Growing applications of hyperspectral and multispectral imaging [Capitolo/Saggio]
Calvini, R.; Ulrici, A.; Amigo, J. M.
abstract

Hyperspectral and multispectral imaging (HSI and MSI, respectively) are well-known imaging techniques that have their origin in remote sensing. Nevertheless, the versatility of having a camera with the integration of a spectrometer for each pixel has profited many other branches of science and industry. Nowadays they are used in precision agriculture, pharmaceutical production, artworks, biochemistry, etc. There are several fields in which their implementation is still growing and being adapted to the requirements of the field. This chapter will review some of them, such as their implementation in waste sorting, forensic sciences, archaeology, or entomology. Of course, there are many other fields of expertise taking benefits from HSI and MSI. These are just some examples of unusual applications of HSI and MSI where we believe that there is still a vast potential for growth.


2020 - Hermetia illucens (L.) larvae as chicken manure management tool for circular economy [Articolo su rivista]
Bortolini, Sara; Macavei, Laura Ioana; Saadoun, Jasmine Hadj; Foca, Giorgia; Ulrici, Alessandro; Bernini, Fabrizio; Malferrari, Daniele; Setti, Leonardo; Ronga, Domenico; Maistrello, Lara
abstract

The increased request for poultry meat and eggs of a rising human population requires more efficient and cleaner methods to manage increasing quantities of chicken manure. The black soldier fly Hermetia illucens is known as an efficient bio-converter of organic waste in proteins and fats, with the advantage that the larval frass is supposed to have compost-like properties. In the view to identify the operating conditions for the sustainable management and valorization of livestock waste at a pre-industrial scale, this study is aimed at: i) optimizing the growth of H. illucens on a mixture of chicken manure, chabazite and water; ii) assessing the soil amendment properties of the larval frass obtained from the optimized mixture. Preliminary trials allowed defining the basic rearing conditions in terms of temperature and substrate components. A mixture design based on a special cubic model allowed identifying the best mixture for H. illucens larvae growth, which consists in 34.5% chicken manure, 58.3% water and 7.2% coarse chabazite. This mix led to about 86% of alive prepupae weighting 90 mg on average, and to a reduction of the initial substrate amount by more than 75%. The larval frass obtained from this mixture showed soil improver properties, suggesting its use to supply the common peat based growing media for potted baby-leaf lettuce production. Overall, H. illucens larvae have proved to be a useful tool to favor a more sustainable management of chicken manure by strongly reducing its amount and closing its recovery cycle obtaining high value products for agricultural purposes.


2020 - Multi-target prediction of wheat flour quality parameters with near infrared spectroscopy [Articolo su rivista]
Barbon Junior, S.; Mastelini, S. M.; Barbon, A. P. A. C.; Barbin, D. F.; Calvini, R.; Lopes, J. F.; Ulrici, A.
abstract

Near Infrared (NIR) spectroscopy is an analytical technology widely used for the non-destructive characterisation of organic samples, considering both qualitative and quantitative attributes. In the present study, the combination of Multi-target (MT) prediction approaches and Machine Learning algorithms has been evaluated as an effective strategy to improve prediction performances of NIR data from wheat flour samples. Three different Multi-target approaches have been tested: Multi-target Regressor Stacking (MTRS), Ensemble of Regressor Chains (ERC) and Deep Structure for Tracking Asynchronous Regressor Stack (DSTARS). Each one of these techniques has been tested with different regression methods: Support Vector Machine (SVM), Random Forest (RF) and Linear Regression (LR), on a dataset composed of NIR spectra of bread wheat flours for the prediction of quality-related parameters. By combining all MT techniques and predictors, we obtained an improvement up to 7% in predictive performance, compared with the corresponding Single-target (ST) approaches. The results support the potential advantage of MT techniques over ST techniques for analysing NIR spectra.


2020 - Multivariate image analysis for the rapid detection of residues from packaging remnants in former foodstuff products (FFPs)–a feasibility study [Articolo su rivista]
Calvini, R.; Luciano, A.; Ottoboni, M.; Ulrici, A.; Tretola, M.; Pinotti, L.
abstract

From a circular economy perspective, feeding livestock with food leftovers or former foodstuff products (FFPs) could be an effective option aimed at exploiting food leftover resources and reducing food losses. FFPs are valuable energy sources, characterised by a beneficial starch/sugar content, and also fats. However, besides these nutritional aspects, safety is a key concern given that FFPs are generally derived from packaged food. Packaging materials, such as plastics and paper, are not accepted as a feed ingredient which means that residues should be rigorously avoided. A sensitive and objective detection method is thus essential for an accurate risk evaluation throughout the former food production chain. To this end, former food samples were collected in processing plants of two different European countries and subjected to multivariate analysis of red, green, and blue (RGB) microscopic images, in order to evaluate the possible application of this non-destructive technique for the rapid detection of residual particles from packaging materials. Multivariate Image Analysis (MIA) was performed on single images at the pixel level, which essentially consisted in an exploratory analysis of the image data by means of Principal Component Analysis, which highlighted the differences between packaging and foodstuff particles, based on their colour. The whole dataset of images was then analysed by means of a multivariate data dimensionality reduction method known as the colourgrams approach, which identified clusters of images sharing similar features and also highlighted outlier images due to the presence of packaging particles. The results obtained in this feasibility study demonstrated that MIA is a promising tool for a rapid automated method for detecting particles of packaging materials in FFPs.


2019 - Data fusion of electronic eye and electronic tongue signals to monitor grape ripening [Articolo su rivista]
Orlandi, Giorgia; Calvini, Rosalba; Foca, Giorgia; Pigani, Laura; Vasile Simone, Giuseppe; Ulrici, Alessandro
abstract

Two separate artificial sensors, an electronic eye (EE) and an electronic tongue (ET), were recently developed to monitor grape ripening based on the analysis of must. The aim of this research is to exploit the complementary information obtained by means of EE and ET sensing systems using different data fusion strategies, in order to develop an integrated device able to quickly and easily quantify the physico-chemical parameters that are used to assess phenolic ripeness. To this purpose, both low-level and mid-level data fusion approaches were investigated. Partial Least Squares (PLS) regression was applied to the fused data, with the aim of relating the information brought by the two sensors with twelve physico-chemical parameters measured on the must samples by standard analytical methods. The results achieved with mid-level data fusion outperformed those obtained using EE and ET separately, and highlighted that both the artificial sensors have made a significant contribution to the prediction of each one of the considered physico-chemical parameters.


2019 - Land Snails as a Valuable Source of Fatty Acids: A Multivariate Statistical Approach [Articolo su rivista]
Galluzzo, Francesco Giuseppe; Cammilleri, Gaetano; Ulrici, Alessandro; Calvini, Rosalba; Pulvirenti, Andrea; Lo Cascio, Giovanni; Macaluso, Andrea; Vella, Antonio; Cicero, Nicola; Amato, Andtonella; Ferrantelli, Vincenzo
abstract

The fatty acid (FA) profile of wild Theba pisana, Cornu aspersum, and Eobania vermiculata land snail samples, collected in Sicily (Southern Italy), before and after heat treatment at +100 °C were examined by gas chromatography with a flame ionization detector (GC‐FID). The results show a higher content of polyunsaturated fatty acids (PUFAs) in all of the examined raw snails samples, representing up to 48.10% of the total fatty acids contents, followed by monounsaturated fatty acids (MUFAs). The thermal processing of the snail samples examined determined an overall reduction of PUFA levels (8.13%, 7.75%, and 4.62% for T. pisana, C. aspersum and E. vermiculata samples, respectively) and a species‐specific variation of saturated fatty acid (SFA) contents. Oleic acid remained the most abundant FA of all of the snails species examined, accounting for up to 29.95% of the total FA content. A relevant decrease of ɷ3/ɷ6 ratio was found only for T. pisana samples. The principal component analysis (PCA) showed a separation of the snail samples in terms of species and heat treatment. The results of this work suggest land snails as a valuable source of MUFA and PUFA contents and boiling as appropriate treatment, according to the maintenance of healthy properties.


2019 - Microbiota of sliced cooked ham packaged in modified atmosphere throughout the shelf life: Microbiota of sliced cooked ham in MAP [Articolo su rivista]
Raimondi, Stefano; Luciani, Rosaria; Sirangelo, Tiziana Maria; Amaretti, Alberto; Leonardi, Alan; Ulrici, Alessandro; Foca, Giorgia; D'Auria, Giuseppe; Moya, Andrés; Zuliani, Véronique; Seibert, Tim Martin; Søltoft-Jensen, Jakob; Rossi, Maddalena
abstract

Fourteen lots of cooked ham in modified atmosphere packaging (CH) were analyzed within a few days from packaging (S) and at the end of the shelf-life (E), after storage at 7 °C to simulate thermal abuse. Five more lots, rejected from the market because spoiled (R), were included in the study. Quality of the products was generally compromised during the shelf life, with only 4 lots remaining unaltered. Analysis of 16S rRNA gene amplicons resulted in 801 OTUs. S samples presented a higher diversity than E and R ones. At the beginning of the shelf life, Proteobacteria and Firmicutes dominated the microbiota, with Acinetobacter, Brochothrix, Carnobacterium, Lactobacillus, Prevotella, Pseudomonas, Psychrobacter, Weissella, Vibrio rumoiensis occurring frequently and/or abundantly. E and R samples were dominated by Firmicutes mostly ascribed to Lactobacillales. It is noteworthy the appearance of abundant Leuconostoc, negligible in S samples, in some E and R samples, while in other LAB were outnumbered by V. rumoiensis or Brochothrix thermosphacta. The microbiota of spoiled and R samples could not be clustered on the basis of specific defects (discoloration, presence of slime, sourness, and swollen packages) or supplemented additives. LAB population of S samples, averaging 2.9 log10(cfu/g), increased to 7.7 log10(cfu/g) in the E and R samples. Dominant cultivable LAB belonged to the species Lactobacillus sakei and Leuconostoc carnosum. The same biotypes ascribed to different species where often found in the corresponding S and R samples, and sometime in different batches provided from the same producer, suggesting a recurrent contamination from the plant of production. Consistently with growth of LAB, initial pH (6.26) dropped to 5.74 in E samples. Volatiles organic compound (VOCs) analysis revealed that ethanol was the major metabolite produced during the shelf life. The profile of volatile compounds got enriched with other molecules (e.g. 2-butanone, ethyl acetate, acetic acid, acetoin, butanoic acid, ethyl ester, butanoic acid, and 2,3-butanediol) mainly ascribed to microbial metabolism.


2019 - Multivariate statistical analysis of the polyphenols content for the discrimination of honey produced in Sicily (Southern Italy) [Articolo su rivista]
Lo Dico, Gianluigi Maria; Ulrici, Alessandro; Pulvirenti, Andrea; Cammilleri, Gaetano; Macaluso, Andrea; Vella, Antonio; Giaccone, Vita; Lo Cascio, Giovanni; Graci, Stefania; Scuto, Maria; Trovato Salinaro, Angela; Calabrese, Vittorio; Lo Dico, Rea; Ferrantelli, Vincenzo
abstract

The polyphenols content of 105 honey samples produced by black honeybees (Apis Mellifera ssp. Sicula) and common honeybees (Apis mellifera ssp. Ligustica) from Western Sicily (Southern Italy) was examined using TurboFlow™ liquid chromatography Orbitrap™ high-resolution mass spectrometry. The results showed very high kaempferol and quercetin contents, with average values higher than what was reported in literature (3967.9±2184.16 and 2206.1±1666.4μg kg⁠−1 for kaempferol and quercetin, respectively). The honey samples produced by Apis Mellifera ssp. Sicula subspecies showed polyphenols content up to two times higher than Apis mellifera ssp. Ligustica. The Principal Component Analysis (PCA) model calculated on the polyphenols content showed a satisfactory separation of the honey samples in terms of honeybee subspecies and production area. The model proposed in this work shows the possibility to safeguard the authenticity of the honey produced in the various geographic areas of Sicily.


2019 - Occhio e lingua elettronici ci dicono se l’uva è matura [Articolo su rivista]
Foca, G.; Calvini, R.; Orlandi, G.; Pigani, L.; Masino, F.; Ulrici, A.
abstract


2018 - Apparato e metodo per determinare parametri fisici e chimici di un campione disomogeneo tramite acquisizione ed elaborazione di immagini a colori del campione [Brevetto]
Ulrici, Alessandro; Calvini, Rosalba; Foca, Giorgia; Orlandi, Giorgia; Antonelli, Andrea
abstract

L’invenzione consiste in un dispositivo portatile compatto, economico e di semplice utilizzo per il monitoraggio in campo del grado di maturazione fenolica dell’uva mediante l'analisi di immagini acquisite utilizzando uno smartphone.


2018 - Automated quantification of defective maize kernels by means of Multivariate Image Analysis [Articolo su rivista]
Orlandi, Giorgia; Calvini, Rosalba; Foca, Giorgia; Ulrici, Alessandro
abstract

This article describes the development of a fast and inexpensive method based on digital image analysis for the automated quantification of the percentage of defective maize (%DM). Defective kernels tend to foster high levels of mycotoxins like Deoxynivalenol (DON), which represents a risk for the health of humans and of farm animals. In this work, 332 RGB images of 83 mixtures containing different amounts of defective maize kernels were acquired using a digital camera. The mixtures were also analysed with a commercial ELISA test kit to determine their concentration of DON, that resulted highly correlated with the amount of defective kernels. Each image was then converted into a signal, named colourgram, which codifies its colour-related information content. The colourgrams were firstly explored using Principal Component Analysis. Then, calibration models of the %DM values were developed using Partial Least Squares (PLS) and interval PLS. The best interval PLS model allowed to predict the %DM values of external test set samples with a root mean square error value equal to 2.6%. Based on the output of this model it was also possible to highlight the defective-maize areas within the images, confirming the significance of the proposed approach. (C) 2017 Elsevier Ltd. All rights reserved.


2018 - Bacterial community of Industrial raw Sausage Packaged in Modified Atmosphere throughout the Shelf Life [Articolo su rivista]
Raimondi, Stefano; Nappi, Maria Rosaria; Sirangelo, Tiziana M.; Leonardi, Alan; Amaretti, Alberto; Ulrici, Alessandro; Magnani, Rudy; Montanari, Chiara; Tabanelli, Giulia; Gardini, Fausto; Rossi, Maddalena
abstract

Ten lots of industrial raw sausages in modified atmosphere (CO2 30%, O2 70%), produced in the same plant over 7 months, were analyzed at the day after production (S samples) and at the end of shelf life (E samples), after 12 days storage at 7 °C to simulate thermal abuse. Quality of the products was generally compromised by storage at 7 °C, with only 3 E samples without alterations. During the shelf life, the pH decreased for the accumulation of acetic and lactic acids. A few biogenic amines accumulated, remaining below acceptable limits. The profile of volatile compounds got enriched with alcohols, ketones, and acids (e.g. ethanol, 2,3-butanediol, 2,3-butandione, butanoic acid) originated by bacterial metabolism. Throughout the shelf life, aerobic bacteria increased from 4.7 log to 6.6 log cfu/g, and lactic acid bacteria (LAB) from 3.7 to 8.1 log cfu/g. Staphylococci, enterobacteria, and pseudomonads passed from 3.7, 3.0, and 1.7 to 5.5, 4.8, and 3.0 log cfu/g, respectively. Dominant cultivable LAB, genotyped by RAPD-PCR, belonged to the species Lactobacillus curvatus/graminis and Lactobacillus sakei, with lower amounts of Leuconostoc carnosum and Leuconostoc mesenteroides. Brochothrix thermosphacta was the prevailing species among aerobic bacteria. The same biotypes ascribed to several different species where often found in E samples of diverse batches, suggesting a recurrent contamination from the plant of production. Profiling of 16S rRNA gene evidenced that microbiota of S samples clustered in two main groups where either Firmicutes or Bacteroidetes prevailed, albeit with taxa generally associated to the gastro-intestinal tract of mammals. The microbial diversity was lower in E samples than in S ones. Even though a common profile could not be identified, most E samples clustered together and were dominated by Firmicutes, with Lactobacillaceae and Listeriaceae as the most abundant families (mostly ascribed to Lactobacillus and Brochothrix, respectively). In a sole E sample Proteobacteria (especially Serratia) was the major phylum.


2018 - Cimice Asiatica: fitofago chiave in Pianura Padana [Articolo su rivista]
Maistrello, L.; Costi, E.; Bortolini, S.; Macavei, L.; Foca, G.; Ulrici, A.; Vaccari, G.; Caruso, S.; Bortolotti, P. P.; Nannini, R.; Fornaciari, M.; Casoli, L.; Mazzoli, G. L.; Dioli, P.
abstract

Halyomorpha halys a soli due anni dalla sua scoperta ufficiale in Italia nel 2012 era già la specie predominante tra gli eterotteri, oggi è l’insetto chiave dei frutteti. I bordi dei frutteti e le siepi sono i luoghi dove si è registrata la maggiore presenza. Lo studio della sua biologia permetterà di elaborare opportune strategie di difesa integrata, comprendente anche la gestione delle fasce perimetrali


2018 - Development of an automated method for the identification of defective hazelnuts based on RGB image analysis and colourgrams [Articolo su rivista]
Giraudo, A.; Calvini, R.; Orlandi, G.; Ulrici, A.; Geobaldo, F.; Savorani, F.
abstract

Over the past decades, Red-Green-Blue (RGB) image analysis has gained increasing importance in industrial applications, since it has widely proved to be a suitable tool for food quality and process control. This article describes the development of a fast and objective method for the automated identification of defective hazelnut kernels based on multivariate analysis of RGB images. To this aim, an overall sample set of 2000 half-cut hazelnut kernels, previously assigned by industrial expert assessors as sound or defective (i.e. rotten or pest-affected), was collected and imaged using a digital camera. The colour-related information of the images was converted into one-dimensional signals, named colourgrams, which were firstly explored through the Principal Component Analysis and subsequently used to build classification models, based on both Partial Least Square-Discriminant Analysis (PLS-DA) and interval-PLS-DA (iPLS-DA) algorithms. A tree-structure hierarchical classification approach has been considered, i.e. the discrimination between sound and defective kernels as a first rule, and the discrimination between the two types of defect as a second rule. The best sound vs defective classification model was able to correctly recognize approximately the 97% of the test set defective samples, while the best rotten vs pest-affected model allowed classifying correctly more than 92% of the test set samples. Moreover, the image reconstruction performed using the selected colourgram features led to an exhaustive interpretation of the decision-making criteria adopted by the classification algorithms and further confirmed the reliability of the proposed method.


2018 - Developmentof a classification algorithm for efficient handling of multiple classes in sorting systems based on hyperspectral imaging [Articolo su rivista]
Calvini, Rosalba; Orlandi, Giorgia; Foca, Giorgia; Ulrici, Alessandro
abstract

When dealing with practical applications of hyperspectral imaging, the development of efficient, fast and flexible classification algorithms is of the utmost importance. Indeed, the optimal classification method should be able, in a reasonable time, to maximise the separation between the classes of interest and, at the same time, to correctly reject possible outlier samples. To this aim, a new extension of Partial Least Squares Discriminant Analysis (PLS-DA), namely Soft PLS-DA, has been implemented. The basic engine of Soft PLS-DA is the same as PLS-DA, but class assignment is subjected to some additional criteria which allow samples not belonging to the target classes to be identified and rejected. The proposed approach was tested on a real case study of plastic waste sorting based on near infrared hyperspectral imaging. Household plastic waste objects made of the six recyclable plastic polymers commonly used for packaging were collected and imaged using a hyperspectral camera mounted on an industrial sorting system. In addition, paper and not recyclable plastics were also considered as potential foreign materials that are commonly found in plastic waste. For classification purposes, the Soft PLS-DA algorithm was integrated into a hierarchical classification tree for the discrimination of the different plastic polymers. Furthermore, Soft PLS-DA was also coupled with sparse-based variable selection to identify the relevant variables involved in the classification and to speed up the sorting process. The tree-structured classification model was successfully validated both on a test set of representative spectra of each material for a quantitative evaluation, and at the pixel level on a set of hyperspectral images for a qualitative assessment.


2018 - Electronic eye for the prediction of parameters related to grape ripening [Articolo su rivista]
Orlandi, G.; Calvini, R.; Pigani, L.; Foca, G.; Vasile Simone, G.; Antonelli, A.; Ulrici, A.
abstract

An electronic eye (EE) for fast and easy evaluation of grape phenolic ripening has been developed. For this purpose, berries of different grape varieties were collected at different harvest times from veraison to maturity, then an amount of the derived must was deposited on a white sheet of absorbent paper to obtain a sort of paper chromatography. Thus, RGB images of the must spots were collected using a flatbed scanner and converted into one-dimensional signals, named colourgrams, which codify the colour properties of the images. The dataset of colourgrams was used to build calibration models to relate the colour of the images with the phenolic composition of the samples – determined by reference analytical methods – and therefore to follow the ripening trend. Satisfactory calibration models were obtained for the prediction of the most important parameters related to phenolic ripening of grapes, such as colour index, tonality, total anthocyanins content, malvidin-3-O-glucoside and petunidin-3-O-glucoside.


2018 - L’invasiva Halyomorpha halys è fitofago chiave dei frutteti: risultati del monitoraggio triennale in Emilia. [Relazione in Atti di Convegno]
Maistrello, L.; Vaccari, G.; Caruso, S.; Costi, E.; Bortolini, S.; Macavei, LAURA IOANA; Foca, G.; Ulrici, A.; Bortolotti, P. P.; Nannini, R.; Casoli, L.; Fornaciari, M.; Mazzoli, G. L.; Dioli, P.
abstract

The brown marmorated stink bug Halyomorpha halys was detected for the first time in Italy in 2012 in the province of Modena. Between 2014 and 2016, a specific monitoring program was carried out in some farms in the provinces of Modena and Reggio Emilia, focusing on pear orchards and the adjacent uncultivated areas (hedges and herbaceous areas) using active techniques to assess the abundance, seasonality and impact of H. halys and other phytophagous Heteroptera. The results showed that just a few years after the first detection, this invasive species largely outperforms all other Heteroptera, and is a seasonal-long pest that caused considerable damage in several farms, with over 50% deformed fruits. The mirids are found mainly in herbaceous areas and crops, while the other phytophagous Heteroptera, only occasionally found in the orchard, are mainly found on the hedges and in other crops. The present survey demonstrates for the first time the great damaging potential of H. halys as a new key pest for fruit orchards in southern Europe.


2018 - Prediction of parameters related to grape ripening by multivariate calibration of voltammetric signals acquired by an electronic tongue [Articolo su rivista]
Pigani, Laura; Vasile Simone, Giuseppe; Foca, Giorgia; Ulrici, Alessandro; Masino, Francesca; Cubillana Aguilera, L.; Calvini, Rosalba; Seeber, Renato
abstract

An electronic tongue (ET) consisting of two voltammetric sensors, namely a poly-ethylendioxythiophene modified Pt electrode and a sonogel carbon electrode, has been developed aiming at monitoring grape ripening. To test the effectiveness of device and measurement procedures developed, samples of three varieties of grapes have been collected from veraison to harvest of the mature grape bunches. The derived musts have been then submitted to electrochemical investigation using Differential Pulse Voltammetry technique. At the same time, quantitative determination of specific analytical parameters for the evaluation of technological and phenolic maturity of each sample has been performed by means of conventional analytical techniques. After a preliminary inspection by principal component analysis, calibration models were calculated both by partial least squares (PLS) on the whole signals and by the interval partial least squares (iPLS) variable selection algorithm, in order to estimate physico-chemical parameters. Calibration models have been obtained both considering separately the signals of each sensor of the ET, and by proper fusion of the voltammetric data selected from the two sensors by iPLS. The latter procedure allowed us to check the possible complementarity of the information brought by the different electrodes. Good predictive models have been obtained for estimation of pH, total acidity, sugar content, and anthocyanins content. The application of the ET for fast evaluation of grape ripening and of most suitable harvesting time is proposed.


2018 - Screening of environmental yeasts for the fermentative production of arabitol from lactose and glycerol [Articolo su rivista]
Amaretti, Alberto; Anfelli, Igor; Foca, Giorgia; Ulrici, Alessandro; Raimondi, Stefano; Leonardi, Alan; Rossi, Maddalena
abstract

Arabitol is a sugar alcohol, stereoisomer to xylitol, which is enlisted among the main target for biorefineries. It can serve as low calorie sweetener and as building block in the enantiopure synthesis of immunosuppressive glycolipids, herbicides, and drugs. Several studies described the fermentative production of arabitol by osmophilic yeasts, cultured with high concentrations of D-glucose. The utilization of cheaper carbon sources, such as glycerol or lactose, is of great interest for biorefinery implementation, but information on exploitation to arabitol production is still scarce. In the present study 50 yeasts belonging to 24 ascomycetous species were screened for the ability to grow and produce arabitol in presence of 80 g/L lactose or glycerol. Production from lactose was generally unsuccessful, the best producer being Kluyveromyces lactis WC 1401 with 0.94 g/L in 160 h. Production from glycerol was promising, with Zygosaccharomyces rouxii WC 1206, Pichia guilliermondii CBS 566, Hansenula anomala WC 1501, and Candida freyschussii ATCC 18737 yielding 3 to 4.5 g/L arabitol, with conversion yield (YP/S) ranging from 11 to 21.7%. Batch growth with high initial glycerol amount (160 g/L) resulted in higher production, with H. anomala WC 1501 yielding 10.0 g/L arabitol (YP/S = 12%) in 160 h. Preliminary bioreactor fermentations with H. anomala WC 1501 indicated that production is not growth associated and revealed some major parameters affecting production, such as the pH and the C:N ratio, that will be the target of following studies aiming at process optimization. Cultivation under controlled oxygenation (DOT = 20%) and pH (= 3.0) resulted in improvement in the performance of H. anomala WC 1501, yielding 16.1 g/L arabitol. Cultivation in a medium with high C:N ratio, lacking inorganic nitrogen yielded 17.1 g/L arabitol. Therefore, this strain was selected for the development of a fed-batch process, aiming to improve the efficiency of the biomass, generated in the growth phase, and increasing the production in the stationary phase.


2018 - Valorisation of chicken manure using insects: Hermetia illucens in the VALORIBIO Project [Abstract in Atti di Convegno]
Bortolini, S.; Macavei, L. I.; Foca, G.; Ulrici, A.; Bernini, F.; Malferrari, D.; Maistrello, L.
abstract

Over the last decades, the need to manage organic waste in a more efficient way and the need to find new sources of energy have opened new horizons in the use of insects for various purposes (e.g. food, feed, biodiesel). The ValoriBio project focuses on the valorisation of chicken manure through the use of Hermetia illucens (Diptera, Stratiomyidae), for the production of high quality compost and bioplastics for agricultural purposes. This study is aimed at the optimisation of the growth parameters of H. illucens on a substrate formed by a mixture of chicken manure, zeolitic tuff (Ca-chabazite), soil improver obtained from pruning shears of urban green, and water. The addition of the Ca-chabazite aims to reduce unpleasant smells, trap the excess of ammonium, and contribute to the formation of a post-breeding substrate which can be used as high-quality compost. The parameters to be maximized were: percentage and maximum average weight of prepupae and percentage of emerged adult flies. Results of a first trial, based on a special cubic model of combined mixture design that tested different ranges of the substrates at 27 and 33°C, recommended the removal of the soil improver and the selection of 27°C as preferred rearing temperature. A second trial considered different ranges of chicken manure, Ca-chabazite (at two different particle sizes) and water. Results from this experiment allowed the definition of the optimal composition for the substrates to obtain the highest percentage of prepupae (71-74%) and the highest average prepupae weight (0.069-0.072g), and were therefore used to plan the validation test, where chicken manure ranged between 34.5 and 45.0%, Ca-chabazite (larger particle size) between 5.0 and 7.2%, and water between 50.0 and 58.3%. These results are the basis to develop an optimized rearing cycle of H. illucens in an automatized pilot plant for organic waste conversion.


2017 - Analog and digital worlds: Part 2. Fourier analysis in signals and data treatment [Articolo su rivista]
Seeber, Renato; Ulrici, Alessandro
abstract

The most direct scope of Fourier Transform (FT) is to give an alternative representation of a signal: from the original domain to the corresponding frequency domain. The original domain can be time, space or any other independent variable that can be used as the domain of the function. This subject has been treated in Part 1 [1]. In particular, the FT of a signal, also referred to as the frequency spectrum of a signal, has been used to calculate the lowest sampling frequency that provides a correct representation of the signal itself. At the beginning of this contribution, it is illustrated how to implement the so-called windowing process to periodic sequences. Then, the meaning of the operations denominated convolution and deconvolution is discussed. It is shown how FT provides a very effective path to the execution of these operations in the alternative domain by employing the convolution theorem. Finally, the application of convolution and deconvolution operations to experimental signals associated with the 'spontaneous' convolution of two concurrent events is analysed by different examples.


2017 - Biomass production and dry matter partitioning of processing tomato under organic vs conventional cropping systems in a Mediterranean environment [Articolo su rivista]
Ronga, Domenico; Zaccardelli, Massimo; Lovelli, Stella; Perrone, Domenico; Francia, Enrico; Milc, Justyna Anna; Ulrici, Alessandro; Pecchioni, Nicola
abstract

Modern agriculture should increase crop sustainability while feeding the growing population. The organic cropping system has emerged as an interesting alternative and more sustainable crop management than conventional one. Unfortunately, the current yield gap between organic and conventional systems is significant for most crops, and this limits the organic system's value. Hence, the objective of this study was to investigate biomass production and partitioning of processing tomato genotypes cultivated in organic vs conventional cropping systems in a processing tomato growing area in the Mediterranean. From 2010–2012, field trials were carried out in two farms in Southern Italy. At the end of the crop cycle and in average among years, processing tomato cultivated in organic cropping system showed reductions of: total biomass dry weight (−25%), leaf area (−36%) and radiation use efficiency (−24%). The biomass distribution to fruits and leaves was highly similar under both managements, while a higher fraction of total biomass was allocated to stems (+34%) and to roots (+41%) in the organic cropping system. In the studied environment, a major cause of different fruit dry weight and, consequently, of yield gap between organic and conventional cropping systems was the reduction of the source, i.e. the lower leaf area, that led to a reduction of total biomass dry weight.


2017 - Characterization of the peptide fraction from digested Parmigiano Reggiano cheese and its effect on growth of lactobacilli and bifidobacteria [Articolo su rivista]
Bottari, Benedetta; Quartieri, Andrea; Prandi, Barbara; Raimondi, Stefano; Leonardi, Alan; Rossi, Maddalena; Ulrici, Alessandro; Gatti, Monica; Sforza, Stefano; Nocetti, Marco; Amaretti, Alberto
abstract

Parmigiano Reggiano (PR) is a raw-milk, hard cooked, long-ripened cheese of high quality and nutritional value. Long ripening times allow for extensive proteolysis of milk proteins to yield a number of peptides, some of which have potential healthy bioactive properties. This study aimed to: i) determine the peptide profile of PR cheese subjected to simulated gastrointestinal transit; ii) evaluate in vitro whether the peptides could support growth of beneficial microbial groups of the gut microbiota. PR samples were subjected to in vitro digestion, simulating oral, gastric, and duodenal transit. Liquid chromatography coupled with tandem mass spectrometry revealed that digestion caused the disappearance of the serum proteins and most of the original peptides, while 71 new peptides were found, all ranging from 2 to 24 residues. The digests were given as sole nitrogen source to pure cultures of Bifidobacterium (27 strains) and Lactobacillus (30 strains), and to bioreactor batch cultures of human gut microbiota. Most of bifidobacteria and lactobacilli grew more abundantly on PR digests than on the control peptone, and exhibited strain- or species-specific peptide preferences, as evidenced by principal component analysis. Bifidobacteria generally consumed a greater amount of peptides than lactobacilli, in terms of both the mean peptide consumption and the number of peptides consumed. For bifidobacteria, peptide preferences were very diverse, but a core of 10 peptides with 4 or 5 residues were consumed by all the strains. Lactobacilli behaved more homogenously and consumed nearly only the same 6 peptides, mostly dipeptides. The peptide preferences of the different groups of bifidobacteria and lactobacilli could not be ascribed to features such as the length of the peptide or the abundance of residues with peculiar properties (hydrophobicity, polarity, charge) and likely depend on specific proteases and/or peptide transporters preferentially recognizing specific sequence motifs. The cultures of human colonic microbiota confirmed that PR digest promoted the growth of commensal bifidobacteria. This study demonstrated that peptides derived from simulated gastrointestinal digestion of PR supported the growth of most lactobacilli and bifidobacteria.


2017 - Determination of the Sugar Content in Commercial Plant Milks by Near Infrared Spectroscopy and Luff-Schoorl Total Glucose Titration [Articolo su rivista]
Marrubini, Giorgio; Papetti, Adele; Genorini, Emiliano; Ulrici, Alessandro
abstract

Thirty-nine samples of plant milks (rice, soy, oat, barley, spelt, quinoa, almond, and a variety of wheat called kamut) were analyzed for their reducing sugars content by NIR spectroscopy, using the Luff-Schoorl official method as reference to build the calibration models. The amount of reducing sugars, expressed as grams of glucose/100 mL of beverage, ranged from 0.5 g/100 mL (soy) to 7.6 g/100 mL (rice). Both partial least squares (PLS) and interval-partial least squares regression (iPLS) were used to build multivariate calibration models, testing different spectra preprocessing methods. The performance in prediction of the best calibration model was evaluated on an external test set of nine randomly selected samples (RMSEP = 0.98 g/100 mL, R2PRED = 0.84), and its statistical significance was assessed using a randomization t test based on Monte Carlo simulations. The results obtained suggest that NIR spectroscopy can be a valid alternative to the laborious reference titrimetric method for the determination of total glucose content in plant milks.


2017 - Development of a flexible Computer Vision System for marbling classification [Articolo su rivista]
Barbon, Ana Paula Ayub da Costa; Barbon, Sylvio; Campos, Gabriel Fillipe Centini; Seixas, José Luis; Peres, Louise Manha; Mastelini, Saulo Martielo; Andreo, Nayara; Ulrici, Alessandro; Bridi, Ana Maria
abstract

Traditional marbling meat evaluation is a tedious, repetitive, costly and time-consuming task performed by panellists. Alternatively, we have Computer Vision Systems (CVS) to mitigate these problems. However, most of CVS are restricted to specific environments, configurations or muscle types, and marbling scores are settled for a particular marbling meat standard. In this context, we developed a CVS for meat marbling grading, which is flexible to different muscle colour contrasts and grading standards. Essentially, the proposed method segments an image pre-processed by illumination normalisation and contrast enhancement, analyses visible intramuscular fat pixels and attributes a score based on a desired meat standard defined in the learning step. Learning approach is an instance-based system making use of k-Nearest Neighbours algorithm (k-NN) to attribute a score from segmentation results. The algorithm classifies the new samples based on scores assigned by panellists. We investigated the optimal number of samples for modelling, focusing on the smallest number leading to acceptable accuracy, and considering two different animal species: bovine and swine. The CVS led to accuracy values equal to 81.59% (bovine) and to 76.14% (swine), using only three samples for each marbling score.


2017 - MICROBIOTA OF FRESH CURED PORK SAUSAGE OVER THE SHELF-LIFE [Poster]
Luciani, Rosaria; Raimondi, Stefano; Tabanelli, Giulia; Montanari, Chiara; SIRANGELO Tiziana, M.; Amaretti, Alberto; Leonardi, Alan; Ulrici, Alessandro; Foca, Giorgia; Gardini, Fausto; Rossi, Maddalena
abstract

Italian style fresh sausage is a traditional pork food, commonly consumed after cooking. It is a perishable product that over the time can be colonized by spoilage bacteria that render the product inacceptable because of undesirable modifications of sensorial properties, such as appearance, texture, odor, and flavor. Indeed, being fresh meat a matrix with high water activity, slightly acidic pH, and high level of nutrients including glucose, lactic acid, nitrogenous compounds, and amino acids, it allows growth and proliferation of several bacteria. Temperatures and MAP (Modified Atmosphere Packaging) are the most important extrinsic factors affecting growth of microorganism. Generally fresh sausages are conserved refrigerated in MAP to maintain the red colour of the meat. The refrigeration of raw meat slows down growth of bacteria, allowing selection and blooming of psychrotrophic aerobic and aerotolerant species.


2017 - Monitoring of the invasive Halyomorpha halys, a new key pest of fruit orchards in northern Italy [Articolo su rivista]
Maistrello, Lara; Vaccari, Giacomo; Caruso, Stefano; Costi, Elena; Bortolini, Sara; Macavei, Laura Ioana; Foca, Giorgia; Ulrici, Alessandro; Bortolotti, Pier Paolo; Nannini, Roberta; Casoli, Luca; Fornaciari, Massimo; Mazzoli, Gian Lorenzo; Dioli, Paride
abstract

Halyomorpha halys is an invasive polyphagous pest with a high negative impact on fruit orchards and other agricultural crops in the USA. In Italy, it was first detected in 2012 in Emilia Romagna, a northern region that is among the major European tree fruit production areas. A specific monitoring programme using active techniques was carried out in pear orchards and adjacent uncultivated areas between 2014 and 2016 to assess the abundance, seasonality and impact of H. halys and other phytophagous Heteroptera in the field. It emerged that just a few years after first discovery, this invasive species already largely outnumbers all the other Heteroptera and that it is a season-long pest for pear crops. Severe yield losses are reported in different farms, especially on the orchard borders, with more than 50% deformed fruits. Mirids are mostly found in the grassy areas and crops, and the other phytophagous Heteroptera, only occasionally detected in the orchard trees, occur mainly on hedges and other crops. Our survey demonstrates for the first time the great damaging potential of H. halys as a new key pest of orchards in southern Europe. The study also identified the patterns of seasonal abundance of adults and nymphs in the orchards and their uncultivated surroundings, providing baseline data for the development of specific strategies for sustainable management.


2017 - Transferring results from NIR-hyperspectral to NIR-multispectral imaging systems: A filter-based simulation applied to the classification of Arabica and Robusta green coffee [Articolo su rivista]
Calvini, Rosalba; Amigo, Jose Manuel; Ulrici, Alessandro
abstract

Due to the differences in terms of both price and quality, the availability of effective instrumentation to discriminate between Arabica and Robusta coffee is extremely important. To this aim, the use of multispectral imaging systems could provide reliable and accurate real-time monitoring at relatively low costs. However, in practice the implementation of multispectral imaging systems is not straightforward: the present work investigates this issue, starting from the outcome of variable selection performed using a hyperspectral system. Multispectral data were simulated considering four commercially available filters matching the selected spectral regions, and used to calculate multivariate classification models with Partial Least Squares-Discriminant Analysis (PLS-DA) and sparse PLS-DA. Proper strategies for the definition of the training set and the selection of the most effective combinations of spectral channels led to satisfactory classification performances (100% classification efficiency in prediction of the test set).


2016 - Agronomic and molecular evaluation of cocksfoot and tall fescue cultivars for adaptation to an Algerian drought-prone environment [Articolo su rivista]
Mefti, M; Bouzerzour, H; Francia, Enrico; Ulrici, Alessandro; Abdelguerfi, A; Barre, P; Pecchioni, Nicola
abstract

A prime objective for improving perennial grasses for Mediterranean environments is the identification and selection of genotypes well adapted to semi-arid conditions. This study was conducted at an experimental site in Algeria over three consecutive seasons, with the aim of evaluating the agronomic performance and genetic diversity of 13 cultivars of two species of perennial grasses: six cocksfoot (Dactylis glomerata L.) and seven tall fescue (Festuca arundinacea Schreb. = syn.Lolium arundinaceum (Schreb.) Darbysh.) cultivars. Variation was found in both species for dry-matter yield, sward recovery, heading date, water-use efficiency (WUE), and summer senescence. Tall fescue cultivars gave greater yield in spring, with earlier heading date and higher WUE than cocksfoot, with no differences for the other traits. Among the genotypes, `Flecha' was the most promising, together with `E-542', `Fraydo' and `Centurion', all of which are tall fescue cultivars. Principal component analysis indicated that persistence of grass cover is relatively independent from dry-matter yield and water-use efficiency. The level of genetic diversity within each species was assessed using AFLP markers, and the molecular variation was analysed together with agronomic trait variation, with identification of molecular markers potentially associated with the relevant traits.


2016 - Analog and digital worlds: Part 1. Signal sampling and Fourier Transform [Articolo su rivista]
Seeber, Renato; Ulrici, Alessandro
abstract

Proper data sampling of a continuously varying quantity that describes the proceeding of a natural process leads to a simpler equivalent representation. This representation consists of a sequence of discrete data, which is more suitable to be mathematically handled and allows one not to lose essential information provided by the original signal. The discrete values of the sequence obtained by sampling differ from one another by finite quantities. In the ideal case, the original representation should be perfectly reconstructed by a backward procedure. The rules that should be respected in order to satisfy this basic condition are very simple, but require the decomposition of the signal into a suitable set of elementary components. This may be performed by applying to the sequence the algorithm called Discrete Fourier Transform (DFT). The direct result of the transformation consists of the spectrum of the signal, which can be analysed in many ways. The mathematics to make the FT algorithm work, eventually in an as fast as possible way (FFT – Fast Fourier Transform) is perhaps of less interest to the chemists and will not be treated here. Rather, the aim is to address the reader about what FT allows to obtain.


2016 - Calculating the iodine value for Italian heavy pig subcutaneous adipose tissue from fatty acid methyl ester profiles [Articolo su rivista]
Lo Fiego, Domenico Pietro; Minelli, Giovanna; Volpelli, Luisa Antonella; Ulrici, Alessandro; Macchioni, Paolo
abstract

In this work, different equations were compared as for their effectiveness in predicting the iodine value (IV), based on fatty acid (FA) composition of subcutaneous adipose tissue of Italian heavy pigs. In particular, six equations were tested: AOCS (1); modified AOCS (2), including all unsaturated FA (UFA); regression models obtained using the stepwise regression procedure as variable selection method, calculated considering only UFA (3) or all the FA (4); regression models obtained using the backward elimination procedure, calculated considering only UFA (5) or all the FA (6). The comparison of the equations performance, estimated using an external test set, showed that the use of regression models led to significant enhancements of prediction accuracy with respect to the AOCS equations. Using both equations 4 and 6, the average paired differences between experimental and predicted IV values were not statistically significant. Therefore, it is possible to use these equations for IV estimation of the subcutaneous adipose tissue of Italian heavy pigs.


2016 - Data dimensionality reduction and data fusion for fast characterization of green coffee samples using hyperspectral sensors [Articolo su rivista]
Calvini, Rosalba; Foca, Giorgia; Ulrici, Alessandro
abstract

Hyperspectral sensors represent a powerful tool for chemical mapping of solid-state samples, since they provide spectral information localized in the image domain in very short times and without the need of sample pretreatment. However, due to the large data size of each hyperspectral image, data dimensionality reduction (DR) is necessary in order to develop hyperspectral sensors for real-time monitoring of large sets of samples with different characteristics. In particular, in this work, we focused on DR methods to convert the three-dimensional data array corresponding to each hyperspectral image into a one-dimensional signal (1D-DR), which retains spectral and/or spatial information. In this way, large datasets of hyperspectral images can be converted into matrices of signals, which in turn can be easily processed using suitable multivariate statistical methods. Obviously, different 1D-DR methods highlight different aspects of the hyperspectral image dataset. Therefore, in order to investigate their advantages and disadvantages, in this work, we compared three different 1D-DR methods: average spectrum (AS), single space hyperspectrogram (SSH) and common space hyperspectrogram (CSH). In particular, we have considered 370 NIR-hyperspectral images of a set of green coffee samples, and the three 1D-DR methods were tested for their effectiveness in sensor fault detection, data structure exploration and sample classification according to coffee variety and to coffee processing method. Principal component analysis and partial least squares-discriminant analysis were used to compare the three separate DR methods. Furthermore, low-level and mid-level data fusion was also employed to test the advantages of using AS, SSH and CSH altogether. [Figure not available: see fulltext.]


2016 - Determination of polyphenol content and colour index in wines through PEDOT-modified electrodes [Articolo su rivista]
Pigani, Laura; Rioli, Cristina; Foca, Giorgia; Ulrici, Alessandro; Seeber, Renato; Terzi, Fabio; Zanardi, Chiara
abstract

Poly(3,4-ethylenedioxythiophene)-modified electrodes have been used for the estimation of the polyphenolic content and of the colour index of different samples of wines. Synthetic wine solutions, prepared with different amount of oenocyanins, have been analysed spectrophotometrically and electrochemically in order to find a correlation between the total polyphenolic content or colour index and the current peak. The regression curves obtained have been used as external calibration lines for the analysis of several commercial wines, ranging from white to dark red wines. In this way, a rapid estimation of the total polyphenolic content and of the colour index may be accomplished from a single voltammetric measurement. Furthermore, principal component analysis has also been used to evaluate the effect of total polyphenolic content and colour index on the whole voltammetric signals within a selected potential range, both for the synthetic solutions and for the commercial products.


2016 - Iodine Value and Fatty Acids Determination on Pig Fat Samples by FT-NIR Spectroscopy: Benefits of Variable Selection in the Perspective of Industrial Applications [Articolo su rivista]
Foca, Giorgia; Ferrari, Carlotta; Ulrici, Alessandro; Ielo, Maria Cristina; Minelli, Giovanna; Lo Fiego, Domenico Pietro
abstract

In this work, FT-NIR spectroscopy was employed to determine iodine value (IV) and fatty acids (FA) content of pig fat samples, through the combined use of signal preprocessing, multivariate calibration, and variable selection methods. In particular, the main focus was on the use of variable selection methods, both in order to improve the predictive performance of the calibration models, and to identify relevant wavelengths that could be subsequently used for the development of simple, fast, and cheap hand-held devices, able to measure IV and FA content directly on the fat without the need of any sample pretreatment. Firstly, for each property of interest, partial least squares (PLS) multivariate calibration models were calculated considering the whole spectral range and testing different signal preprocessing methods. Then, once chosen the optimal signal preprocessing method, a two-step variable selection procedure was applied. In the first step, the interval-PLS variable selection algorithm was used to calculate a set of calibration models, whose outcomes were considered altogether in the second step, in order to select the optimal calibration model. The variable selection procedure allowed to lower the number of spectral variables retained by the model, and often led to an increase of the performance in prediction of the external test set samples.


2016 - Mining metagenomic whole genome sequences revealed subdominant but constant Lactobacillus population in the human gut microbiota [Articolo su rivista]
Rossi, Maddalena; Martínez Martínez, Daniel; Amaretti, Alberto; Ulrici, Alessandro; Raimondi, Stefano; Moya, Andrés
abstract

The genus Lactobacillus includes over 215 species that colonize plants, foods, sewage and the gastrointestinal tract (GIT) of humans and animals. In the GIT, Lactobacillus population can be made by true inhabitants or by bacteria occasionally ingested with fermented or spoiled foods, or with probiotics. This study longitudinally surveyed Lactobacillus species and strains in the feces of a healthy subject through whole genome sequencing (WGS) data-mining, in order to identify members of the permanent or transient populations. In three time-points (0, 670 and 700 d), 58 different species were identified, 16 of them being retrieved for the first time in human feces. L. rhamnosus, L. ruminis, L. delbrueckii, L. plantarum, L. casei and L. acidophilus were the most represented, with estimated amounts ranging between 6 and 8 Log (cells g-1), while the other were detected at 4 or 5 Log (cells g-1). 86 Lactobacillus strains belonging to 52 species were identified. 43 seemingly occupied the GIT as true residents, since were detected in a time span of almost 2 years in all the three samples or in 2 samples separated by 670 or 700 d. As a whole, a stable community of lactobacilli was disclosed, with wide and understudied biodiversity.


2016 - Preliminary analysis of RGB images for the identification of defective maize kernels [Relazione in Atti di Convegno]
Orlandi, Giorgia; Calvini, Rosalba; Foca, Giorgia; Ulrici, Alessandro
abstract

In order to investigate the effectiveness of multivariate image analysis for the evaluation of maize defects, RGB images of maize samples containing different percentages of defective kernels were acquired and then converted into colourgrams, i.e., signals codifying colour-related features. Multivariate analysis of the colourgrams matrix showed a distribution of the acquired samples according to the amount of defective kernels.


2016 - Sparse-Based Modeling of Hyperspectral Data [Capitolo/Saggio]
Calvini, Rosalba; Ulrici, Alessandro; Amigo, J. M.
abstract

One of the main issues of hyperspectral imaging data is to unravel the relevant, yet overlapped, huge amount of information contained in the spatial and spectral dimensions. When dealing with the application of multivariate models in such high-dimensional data, sparsity can improve the interpretability and the performance of the model. In this chapter, we will introduce the exploration of hyperspectral images using a sparse version of the well-known principal component analysis method to demonstrate how the derived models can reveal very useful spectral zones. In particular, we will present two practical applications related to different issues: the separation among groups of homogeneous samples and the identification of outlier pixels in the spatial domain. For both case studies, guidance to the identification of the proper level of sparsity will be provided and, furthermore, we will show how sparsity can improve the chemical interpretation of the results.


2016 - The potential of spectral and hyperspectral-imaging techniques for bacterial detection in food: A case study on lactic acid bacteria [Articolo su rivista]
Foca, Giorgia; Ferrari, Carlotta; Ulrici, Alessandro; Sciutto, Giorgia; Prati, Silvia; Morandi, Stefano; Brasca, Milena; Lavermicocca, Paola; Lanteri, Silvia; Oliveri, Paolo
abstract

Official methods for the detection of bacteria are based on culture techniques. These methods have limitations such as time consumption, cost, detection limits and the impossibility to analyse a large number of samples. For these reasons, the development of rapid, low-cost and non-destructive analytical methods is a task of growing interest. In the present study, the capability of spectral and hyperspectral techniques to detect bacterial surface contamination was investigated preliminarily on gel cultures, and subsequently on sliced cooked ham. In more detail, two species of lactic acid bacteria (LAB) were considered, namely Lactobacillus curvatus and Lactobacillus sakei, both of which are responsible for common alterations in sliced cooked ham. Three techniques were investigated, with different equipment, respectively: a macroscopic hyperspectral scanner operating in the NIR (10,470-5880 cm-1) region, a FT-NIR spectrophotometer equipped with a transmission arm as the sampling tool, working in the 12,500-5800 cm-1 region, and a FT-MIR microscopy operating in the 4000-675 cm-1 region. Multivariate exploratory data analysis, in particular principal component analysis (PCA), was applied in order to extract useful information from original data and from hyperspectrograms. The results obtained demonstrate that the spectroscopic and imaging techniques investigated can represent an effective and sensitive tool to detect surface bacterial contamination in samples and, in particular, to recognise species to which bacteria belong.


2015 - Characterization of common wheat flours (Triticum aestivum L.) through multivariate analysis of conventional rheological parameters and gluten peak test indices [Articolo su rivista]
Marti, Alessandra; Ulrici, Alessandro; Foca, Giorgia; Quaglia, Lucio; Pagani, Maria Ambrogina
abstract

The GlutoPeak consists in high speed mixing of a small amount of wheat flour (<10 g) added with water, and in registering a torque vs. time curve in a very short time (<10 min). Peak torque, peak maximum time, and energy values are calculated from the curve, and used to estimate the aggregation behavior of gluten. The information brought by the GlutoPeak indices is still difficult to interpret correctly, also in relation to the conventional approaches in the field of cereal science. A multivariate approach was used to investigate the correlations existing between the GlutoPeak indices and the conventional rheological parameters. 120 wheat flours- different for protein, dough stability, extensibility, tenacity, and strength, and end-uses - were analyzed using the GlutoPeak and conventional instrumentation. The parameters were subjected to a data exploration step through Principal Component Analysis. Then, multivariate Partial Least Squares Regression (PLSR) models were developed using the GlutoPeak indices to predict the conventional parameters. The values of the squared correlation coefficients in prediction of an external test set showed that acceptable to good results (0.61 ≤ R2PRED ≤ 0.96) were obtained for the prediction of 18 out of the 26 conventional parameters here considered.


2015 - Fast exploration and classification of large hyperspectral image datasets for early bruise detection on apples [Articolo su rivista]
Ferrari, Carlotta; Foca, Giorgia; Calvini, Rosalba; Ulrici, Alessandro
abstract

Hyperspectral imaging allows to easily acquire tens of thousands of spectra for a single sample in few seconds; though valuable, this data-richness poses many problems due to the difficulty of handling a representative amount of samples altogether. For this reason, we recently proposed an approach based on the idea of reducing each image into a one-dimensional signal, named hyperspectrogram, which accounts both for spatial and for spectral information. In this manner, a dataset of hyperspectral images can be easily and quickly converted into a set of signals (2D data matrix), which in turn can be analyzed using classical chemometric techniques. In this work, the hyperspectrograms obtained from a dataset of 800 NIR-hyperspectral images of two different apple varieties were used to discriminate bruised from sound apples using iPLS-DA as variable selection algorithm, which allowed to efficiently detect the presence of bruises. Moreover, the reconstruction as images of the selected variables confirmed that the automated procedure led to the exact identification of the spatial features related to the onset and to the subsequent evolution with time of the bruise defect.


2015 - Physiological responses of processing tomato in organic and conventional Mediterranean cropping systems [Articolo su rivista]
Ronga, Domenico; Lovelli, Stella; Zaccardelli, Massimo; Perrone, Domenico; Ulrici, Alessandro; Francia, Enrico; Milc, Justyna Anna; Pecchioni, Nicola
abstract

Processing tomato is a globally important horticultural crop. It is generally grown in high-input conventional systems, and there is little knowledge regarding its physiological responses in organic cultivation. Therefore, the aim of this work was to determine the influence of organic management on the physiological behavior of cultivars of processing tomato usually cultivated in conventional management in a Mediterranean area. The study was performed by means of: (1) field testing of a set of commercial cultivars for 2 years, in two systems, in one location in Southern Italy, and (2) crop physiological investigations during the growth cycle of processing tomato. Results of the two-year trials indicate that, under the organic cropping system, processing tomato showed, as 2 years average, higher intercellular CO2 concentration (Ci) (+10.3%), transpiration (E) (+15.5%) and stomatal conductance (gs) (+16.5%). Average net assimilation (A) was similar in the two systems and differences were only observed depending on years. In contrast, average leaf area index (LAI) and water use efficiency (WUE) were lower in the organic cropping system (−42% and −17.8%), as were average fruit (FDW) and total (TDW) dry weight (−37.5% and −29%). In our conditions, LAI at the end of the cultivation was highly correlated with total and fruit dry weight. As differences in fruit and total dry weight of processing tomato cannot be explained by differences in net assimilation per leaf area unit, other reasons may be linked to the effects of the organic management on the crop as weeds and pathogens.


2015 - Practical comparison of sparse methods for classification of Arabica and Robusta coffee species using near infrared hyperspectral imaging [Articolo su rivista]
Calvini, Rosalba; Ulrici, Alessandro; Amigo, Jose Manuel
abstract

In the present work sparse-based methods are applied to the analysis of hyperspectral images with the aim at studying their capability of being adequate methods for variable selection in a classification framework. The key aspect of sparse methods is the possibility of performing variable selection by forcing the model coefficients related to irrelevant variables to zero. In particular, two different sparse classification approaches, i.e. sPCA+kNN and sPLS-DA, were compared with the corresponding classical methods (PCA + kNN and PLS-DA) to classify Arabica and Robusta coffee species. Green coffee samples were analyzed using near infrared hyperspectral imaging and the average spectra from each hyperspectral image were used to build training and test sets; furthermore a test image was used to evaluate the performances of the considered methods at pixel-level. In our case, sparse methods led to similar results as classical methods, with the advantage of obtaining more interpretable and parsimonious models. An important result to highlight is that variable selection performed with two different sparse classification approaches converged to the selection of same spectral regions, which implies the chemical relevance of those regions in the discrimination of Arabica and Robusta coffee species.


2014 - A Feature Selection Strategy for the Development of a New Drug Sensing SystemSensors [Relazione in Atti di Convegno]
Ulrici, Alessandro; Calderisi, Marco; Seeber, Renato; J., Uotila; A., Secchi; A. M., Fiorello; M., Dispenza
abstract

In order to efficiently detect four drug precursor molecules in presence of interfering species and background air, using a EC-QCLPAS sensor operating in the mid-infrared region, a complex strategy of spectral response simulation has been developed. In this context, spectra of gases from literature databases have been collected, denoised by means of the Wavelet Transform and mixed together according to a concentration matrix, which was specifically designed to represent a comprehensive combination of possible realistic cases. To scale database spectra to the appropriate concentration levels, an ad-hoc algorithm based on a sigmoidal transfer function has been used. In this way the baseline shape and intensity is preserved. Afterwards, a preliminary wavelength selection has been carried out to exclude noisy regions. The optimal range has finally been defined by maximizing the classification efficiency for all the target gases by means of Partial Least Squares-Discriminant Analysis.


2014 - Algorithms and strategies for extracting optimal information from chemical sensing systems [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Seeber, Renato
abstract

The output signals of chemical sensing systems, i.e. of sensors used to detect chemical quantities, typically consist of a complex superimposition of three different contributions: useful information, non relevant (but systematic) variations, and noise. For an efficient extraction of the highest possible amount of useful information, the application of multivariate methods is definitely more effective than commonly used univariate approaches. However, multivariate methods themselves could not allow the extraction of the whole information content of interest. The goal may be achieved by an efficient use of additional strategies, suitable to consider other aspects such as signal shape, time-evolution of a given sensor response or interactions among signals measured with different sensors. The performance of the sensor(s) is improved and the final output may consist of an optimized set of parameter values.


2014 - Applicazione della spettroscopia FT-NIR per la determinazione degli acidi grassi e del numero di iodio in campioni di grasso suino prelevati da diversi strati sottocutanei [Abstract in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Ferrari, Carlotta; Calvini, Rosalba; Ielo, Maria Cristina; Minelli, Giovanna; LO FIEGO, Domenico Pietro
abstract

La qualità tecnologica e organolettica del grasso suino può essere stimata mediante analisi chimiche quali il numero di iodio e la determinazione gascromatografica della composizione in acidi grassi. Tali metodi, tuttavia, sono lunghi, costosi, dannosi per l’ambiente e non sono adatti per seguire un processo in tempo reale. In questo lavoro, abbiamo valutato la potenzialità della spettroscopia NIR, accoppiata a tecniche chemiometriche appropriate, per predire il numero di iodio e la composizione in acidi grassi di campioni di grasso suino estratti da due diversi strati sottocutanei1, partendo da misure di riferimento acquisite con i metodi tradizionali, analisi di Wijs e analisi gascromatografica. Gli spettri NIR sono stati acquisiti utilizzando due diversi accessori: sfera integratrice e sonda a fibre ottiche. Riguardo alle tecniche chemiometriche, abbiamo utilizzato PCA come metodo di analisi esplorativa, che ha consentito di eliminare i campioni outlier, quindi abbiamo costruito diversi modelli di calibrazione mediante PLS. Successivamente, abbiamo applicato agli spettri anche un metodo di calibrazione con selezione di variabili, iPLS. Poiché non è possibile sapere a priori quale sia il miglior pretrattamento per estrarre l’informazione utile dagli spettri, sono state confrontate diverse combinazioni di pretrattamenti per ottenere il miglior modello. Concludendo, abbiamo discusso i modelli ottenuti al fine di: i) individuare le condizioni operative (considerando sia le condizioni strumentali che le procedure chemiometriche utilizzate) che hanno portato all’ottenimento dei modelli migliori; ii) individuare le regioni spettrali più informative ai fini della calibrazione; iii) ottenere una migliore comprensione delle caratteristiche chimiche del grasso proveniente dai due diversi strati sottocutanei; iv) comprendere quali acidi grassi possano effettivamente essere quantificati con la spettroscopia NIR in un processo reale.


2014 - Classification of Arabica and Robusta coffee samples subjected to different technological treatments using various image analysis methods [Abstract in Atti di Convegno]
Calvini, Rosalba; Foca, Giorgia; Bellucci, L.; Ulrici, Alessandro
abstract

Coffee varietal differentiation based on NIR spectroscopy has been widely investigated in the last 20 years [1-3]. In this work, we have applied hyperspectral imaging in the NIR range (900-1700 nm) for the classification of Arabica and Robusta coffee varieties, considering coffee beans subjected to different processing methods, i.e., the so-called dry method (to produce natural coffee), wet method (to produce washed coffee) and a somewhat intermediate processing method, referred to as polishing method (to produce polished coffee). PCA has been used as an exploratory technique both on the image mean spectra and on the hyperspectrograms obtained from the images. The hyperspectrograms are built by compressing the useful information contained in each hyperspectral image into a signal composed by the frequency distribution curves of quantities calculated by PCA [4]. This procedure allows to compress the information conveyed by the hyperspectral images, maintaining at the same time both spatial- and spectral-related features. The PCA models obtained showed a clear clustering of Arabica and Robusta samples, whereas, considering the technological treatment, the polished coffee samples are clearly distinguishable from the others, while natural and washed coffee samples are quite superimposed. Image mean spectra and hyperspectrograms were then subjected to PLS-DA classification after preprocessing using SNV followed by meancentering or meancentering only. Concerning the discrimination of coffee samples between Arabica and Robusta categories, the same value of classification efficiency in prediction (EFFPRED = 86.3%) has been obtained considering both the mean spectra and the hyperspectrograms. After forward iPLS-DA variable selection, EFFPRED increased up to 98.6% for models calculated using the mean spectra and up to 100% for the models calculated using the hyperspectrograms. As for the discrimination of the coffee samples into the three natural, polished and washed processing categories, the PLS-DA models calculated using mean spectra led to EFFPRED values equal to 81.1%, 95.7% and 49.8%, respectively, while the PLS-DA models calculated using hyperspectrograms led to EFFPRED values equal to 94.7%, 100% and 92.4%, respectively. In this case, iPLS-DA variable selection led to an increase of the performances of the model calculated on mean spectra (EFFPRED equal to 82.9%, 98.6% and 86.5%, respectively) and to a decrease of the performances of the model calculated using hyperspectrograms (EFFPRED equal to 82.9%, 89.3% and 86.5%, respectively).


2014 - Data reduction di immagini iperspettrali: applicazione a problemi di classificazione [Abstract in Atti di Convegno]
Calvini, Rosalba; Ferrari, Carlotta; Foca, Giorgia; Ulrici, Alessandro
abstract

L'imaging iperspettrale (HSI) consente di acquisire in pochi secondi ipercubi di grandi dimensioni, composti da milioni di spettri, che corrispondono a file spesso più grandi di 50 MB. Questa ricchezza di dati rappresenta il principale vantaggio dell’HSI, sebbene causi seri problemi per la gestione dei dati, tali da complicare lo sviluppo di applicazioni industriali efficienti per il controllo in linea. Il nostro gruppo di ricerca ha recentemente proposto un’alternativa1 per trattare dataset composti da decine o centinaia di immagini iperspettrali, che consiste nel convertire ogni immagine iperspettrale in un segnale, chiamato iperspettrogramma, costruito in modo da considerare sia l’informazione di natura spaziale che spettrale. Risulta così possibile trasformare dataset composti da un elevato numero di immagini iperspettrali in matrici bidimensionali di iperspettrogrammi, che a loro volta possono essere analizzate utilizzando i più comuni metodi chemiometrici quali PCA, PLS o PLS-DA. In questo contesto, presentiamo due applicazioni degli iperspettrogrammi per la soluzione di problemi di classificazione. Una prima applicazione riguarda l'individuazione precoce di difetti superficiali in diverse varietà di mele, con particolare attenzione ai campioni in cui il difetto non risulta apprezzabile ad occhio nudo. Le 800 immagini iperspettrali acquisite sono state convertite in iperspettrogrammi permettendo così la riduzione delle dimensioni del dataset da 18.6 GB a 4.7 MB. Inoltre la selezione di variabili mediante iPLS-DA ha permesso di ridurre ulteriormente le dimensioni del dataset e identificare le regioni più rilevanti nel segnale. Il migliore modello iPLSDA, calcolato utilizzando solo 30 variabili delle 1200 iniziali, ha portato ad un valore di efficienza in predizione sul test set esterno pari a 89.6%. Una seconda applicazione riguarda la classificazione di caffè verde appartenente a diverse tipologie: Arabica e Robusta. Prove preliminari hanno mostrato come la classificazione mediante PLS-DA effettuata sugli iperspettrogrammi ha portato ad un valore di efficienza in predizione del 98.3%.


2014 - Detection of contamination by aflatoxins on apricot kernels using NIR-hyperspectral imaging [Abstract in Atti di Convegno]
Calvini, Rosalba; Zivoli, R.; Piemontese, L.; Ferrari, Carlotta; Foca, Giorgia; Perrone, G.; Ulrici, Alessandro; Solfrizzo, M.
abstract

Aflatoxins can be found as contaminants in a wide range of foods, such as nuts, cereals, dried fruits and milk. Due to their hepatotoxic and carcinogenic effects, the maximum allowed concentration of aflatoxins is nowadays regulated in many countries, with levels up to 50 μg/kg. In routine analysis, the main methods used to determine aflatoxins are based on high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) [1]. Despite the very high sensitivity of these methods, they are destructive, expensive, time consuming and not appropriate for real time control, e.g., online. Consequently, the development of fast, non destructive and economic methods for aflatoxins detection and monitoring in food industry is becoming more and more important. Our studies showed that manual sorting of dark or spotted apricot kernels removed 97.3-99.5% of total aflatoxins [2]. However, discolored seeds could be visually identified only after removing the skins from each seed by means of a time-consuming operation. For these reasons, in this work we investigated the possibility to use NIR–HSI for the fast and nondestructive automated identification of aflatoxin contaminated unpeeled apricot kernels. On the whole 9 hyperspectral images, each one containing 48 kernels, were acquired in the 900- 1700 nm range. After image acquisition, the kernels were peeled to identify the dark or spotted kernels and subjected to HPLC analysis for AFB1 quantification. Classification models were then calculated on a training set of NIR spectra extracted from a representative number of non-contaminated and dark seeds, selected on 5 images on the basis of HPLC analysis results as well as of the visual evaluation of the peeled kernels. The remaining 4 images were instead used as independent test set for model validation. Since dark seeds were found to have a higher concentration of AFB1 than spotted seeds, the latter ones were not included in the training set. Different iPLS-DA classification models, built using different signal preprocessing methods and different interval size values, were then evaluated in terms of classification efficiency in cross validation of the training set pixels, in order to select the optimal conditions. The results were reported under the form of predicted probability maps, and for each single kernel the contamination was estimated as the percentage of pixels assigned to the “contaminated” class by the iPLS-DA model.


2014 - Exploration of datasets of hyperspectral images [Abstract in Atti di Convegno]
Ferrari, Carlotta; Calvini, Rosalba; Foca, Giorgia; Ulrici, Alessandro
abstract

Hyperspectral images of size usually greater than 50 MB can be easily acquired in very short times, generally without the need of sample pretreatment. While Multivariate Image Analysis (MIA) tools can be efficiently used for the exploration of single hyperspectral images or of groups composed by a limited number (say up to 10) of merged images, the exploration of datasets composed by a large number (>10) of images is less straightforward. However, a representative sampling of a large number of specimens is frequently required to correctly estimate both intra- and inter-sample variability. This implies the acquisition of datasets composed by a large number of hyperspectral images and of several GB in size, especially in those cases where only one or a few samples can be included in a single image scene. In this context, the exploration of the dataset by applying MIA to single images or to subgroups of merged images does not allow to gain a global overview of the entire dataset variability and to properly highlight the possible presence of outliers, clusters and/or trends. A fast procedure which can be adopted to deal with this issue consists in computing the average spectrum of each image, to build a matrix of average spectra of the analyzed hyperspectral images. Although this approach leads sometimes to satisfactory results (especially when dealing with homogeneous materials), the information related to spatial variability is lost, and the hyperspectral image data are turned into “common” (i.e., not spatially resolved) spectral data. By averaging spectra, for example, the useful information related to the presence of a defect localized in a relatively narrow image area could be diluted within the massive amount of other “well behaving” pixels, becoming no longer detectable. Aiming to develop a fast and easy-to-use tool able to facilitate the exploration of large datasets of hyperspectral images while maintaining both spectral- and spatial-related information of the original images, we have proposed an approach which consists in automatically converting each hyperspectral image into a signal named hyperspectrogram [1]. Essentially, the hyperspectrogram can be viewed as a fingerprint containing the relevant information brought by the original hyperspectral image, and is composed by a first part accounting for the spatial information and by a second part accounting for the spectral information. By representing each image with a vector of few hundreds of points, this procedure enables to compare simultaneously up to hundreds of images by means of common multivariate analysis methods, such as PCA. In order to facilitate the exploration of datasets of hyperspectral images through hyperspectrograms, we have recently developed a Matlab Graphical User Interface (GUI), which easily allows calculation and visualization of hyperspectrograms, exploration of the dataset and visualization of the features of interest contained within each single sample directly in the original image domain.


2014 - Simulation of an experimental database of infrared spectra of complex gaseous mixtures for detecting specific substances. The case of drug precursors [Articolo su rivista]
Calderisi, Marco; Ulrici, Alessandro; Sauli, Sinisalo; Juho, Uotila; Seeber, Renato
abstract

This work is motivated by the need to develop suitable databases in absence of real experimental data, for instance when spectra measured with a newly developed instrumentation on real samples are not available yet. This notwithstanding, in fact, the realization of the physical project should be addressed by a starting database, also invaluable in order to test its effectiveness. In this article we face the issue of simulating gas mixtures spectra for the development of a new sensor for External Cavity-Quantum Cascade Laser Photoacoustic Spectroscopy (EC-QCLPAS) starting from literature FT-IR spectra of pure components: a dataset is realized suitable to realistically represent the ensemble of spectra of the gas mixtures of interest. The informative data deriving from the literature spectra were combined with the stochastic component extracted from a sample spectrum recorded with a prototype instrument, allowing us to build a matrix containing thousands of simulated spectra of gaseous mixtures, accounting for the presence of different components at different concentrations. Signal processing and experimental design techniques were used along the whole path leading to the dataset of simulated spectra. In particular, the goal of the construction of the database lies in the development of a final system to detect drug precursors in the vapour phase. The comparison of some EC-QCLPAS spectra with the corresponding simulated signals confirms the validity of the proposed approach.


2014 - Toward a Compact Instrument for Detecting Drug Precursors in Different EnvironmentsSensors [Relazione in Atti di Convegno]
Terzi, Fabio; Ulrici, Alessandro; Seeber, Renato; A., Secchi; A. M., Fiorello; M., Dispenza; J. C., Antolín; T., Kuusela; A., Varriale; S., D’Auria; I., Tittonen; F., Colao; I., Menicucci; M., Nuvoli; P., Ciambelli; V., Venditto; J., Uotila; G., Maisons; M., Carras
abstract

Law enforcement agencies world-wide are keenly aware that chemical control is a crucial element to monitor the manufacture and distribution of illegal narcotics and synthetic substances. For this purpose components able to perform chemical identifications in contexts such as custom offices are needed, where inspection of trucks, cars, containers, as well as people and baggage, is required. Such components should be assembled as simple machines to be employed on-field by custom officers with no specific skill. In the following the last results of the research project CUSTOM will be presented. The work has been supported by the European Commission under the 7th Framework Programme through the Project SEC-242387: "Drugs and Precursors Sensing by Complementing Low Cost Multiple Techniques" (CUSTOM).


2013 - Classification of pig fat samples from different subcutaneous layers by means of fast and non-destructive analytical techniques [Articolo su rivista]
Foca, Giorgia; Salvo, Davide; Cino, Adelaide; Ferrari, Carlotta; Lo Fiego, Domenico Pietro; Minelli, Giovanna; Ulrici, Alessandro
abstract

In the meat industry the fat portions coming from two different subcutaneous layers, i.e., inner and outer, are destined to the manufacturing of different products, hence the availability of cheap, rapid and affordable methods for the characterization of the overall fat quality is desirable. In this work the potential usefulness of three techniques, i.e. tristimulus colorimetry, FT-NIR spectroscopy and NIR hyperspectral imaging, were tested to rapidly discriminate fat samples coming from the two different layers. To this aim, various multivariate classificationmethodswere used, also including signal processing and feature selection techniques. The classification efficiency in prediction obtained using colorimetric data did not reach excellent results (78.1%); conversely, the NIR-based spectroscopic methods gavemuchmore satisfactorymodels, since they allowed to reach a prediction efficiency higher than 95%. In general, the samples of the outer layer showed a high degree of variability with respect to the samples of the inner layer. This is probably due to a greater variability of the outer samples in terms of fatty acid composition and water amount.


2013 - Efficient chemometric strategies for PET–PLA discrimination in recycling plants using hyperspectral imaging [Articolo su rivista]
Ulrici, Alessandro; S., Serranti; Ferrari, Carlotta; D., Cesare; Foca, Giorgia; G., Bonifazi
abstract

The effectiveness of Hyperspectral imaging (HSI) in the near infrared (NIR) range (1000–1700 nm) was evaluated to discriminate PET (polyethylene terephthalate) from PLA (poly(lactic acid)), two polymers commonly utilized as packaging for foodstuff, in order to improve their further recycling process. An internal calibration based on five reference materials was initially used to eliminate the variability existing among images, then Partial Least Squares-Discriminant Analysis (PLS-DA) was used to distinguish and classify the three classes, i.e., background, PET and PLA. Considering the high amount of data conveyed by the training image, the PLS-DA models were also calculated using as training set a reduced version of the original matrix, with the twofold aim to reduce the computational time and to deal with an equal number of spectra for each class, independently from the initial selected areas. A variable selection procedure by means of iPLS-DA was also applied on both the whole and the reduced matrix. The results obtained on the reduced matrix using only six variables provided a prediction efficiency higher than 98%. Moreover, the possibility to recognize PET and PLA polymers by HSI in the NIR range was further confirmed by using Multivariate Curve Resolution (MCR) as an alternative approach, which also allowed to evaluate the effect of thickness of the transparent plastic samples.


2013 - Handling large datasets of hyperspectral images: Reducing data size without loss of useful information [Articolo su rivista]
Ferrari, Carlotta; Foca, Giorgia; Ulrici, Alessandro
abstract

HyperSpectral Imaging (HSI) is gaining increasing interest in the field of analytical chemistry, since this fast and non-destructive technique allows one to easily acquire a large amount of spectral and spatial information on a wide number of samples in very short times. However, the large size of hyperspectral image data often limits the possible uses of this technique, due to the difficulty of evaluating many samples altogether, for example when one needs to consider a representative number of samples for the implementation of on-line applications. In order to solve this problem, we propose a novel chemometric strategy aimed to significantly reduce the dataset size, which allows to analyse in a completely automated way from tens up to hundreds of hyperspectral images altogether, without losing neither spectral nor spatial information. The approach essentially consists in compressing each hyperspectral image into a signal, named hyperspectrogram, which is created by combining several quantities obtained by applying PCA to each single hyperspectral image. Hyperspectrograms can then be used as a compact set of descriptors and subjected to blind analysis techniques. Moreover, a further improvement of both data compression and calibration/classification performances can be achieved by applying proper variable selection methods to the hyperspectrograms. A visual evaluation of the correctness of the choices made by the algorithm can be obtained by representing the selected features back into the original image domain. Likewise, the interpretation of the chemical information underlying the selected regions of the hyperspectrograms related to the loadings is enabled by projecting them in the original spectral domain. Examples of applications of the hyperspectrogram-based approach to hyperspectral images of food samples in the NIR range (1000-1700 nm) and in the Vis-NIR range (400-1000 nm), facing a calibration and a defect detection issue respectively, demonstrate the effectiveness of the proposed approach.


2013 - Use of multivariate image analysis for the evaluation of total mixed rations in dairy cow feeding [Abstract in Rivista]
Gozzi, Marcello; Ulrici, Alessandro; M., Cardelli; Volpelli, Luisa Antonella
abstract

Multivariate image analysis was applied for the evaluation of total mixed rations (TMR) used in dairy cow feeding. The estimation of the correlations between images and chemical-physical traits of TMR was performed


2012 - A feature selection strategy for the analysis of spectra from a photoacoustic sensing system [Relazione in Atti di Convegno]
Ulrici, Alessandro; Seeber, Renato; Calderisi, Marco; Foca, Giorgia; Juho, Uotila; Mathieu, Carras; Anna Maria, Fiorello
abstract

In the frame of the EU project CUSTOM, a new sensor system for the detection of drug precursors in gaseous samples is being developed, which also includes an External Cavity-Quantum Cascade Laser Photo Acoustic Sensor (ECQCLPAS). In order to define the characteristics of the laser source, the optimal wavenumbers within the most effective 200 cm -1 range in the mid-infrared region must be identified, in order to lead to optimal detection of the drug precursor molecules in presence of interfering species and of variable composition of the surrounding atmosphere. To this aim, based on simulations made with FT-IR spectra taken from literature, a complex multivariate analysis strategy has been developed to select the optimal wavenumbers. Firstly, the synergistic use of Experimental Design and of Signal Processing techniques led to a dataset of 5000 simulated spectra of mixtures of 33 different gases (including the 4 target molecules). After a preselection, devoted to disregard noisy regions due to small interfering molecules, the simulated mixtures were then used to select the optimal wavenumber range, by maximizing the classification efficiency, as estimated by Partial Least Squares - Discriminant Analysis. A moving window 200 cm -1 wide was used for this purpose. Finally, the optimal wavenumber values were identified within the selected range, using a feature selection approach based on Genetic Algorithms and on resampling. The work made will be relatively easily turned to the spectra actually recorded with the newly developed EC-QCLPAS instrument. Furthermore, the proposed approach allows progressive adaptation of the spectral dataset to real situations, even accounting for specific, different environments.


2012 - Automated identification and visualization of food defects using RGB imaging: Application to the detection of red skin defect of raw hams [Articolo su rivista]
Ulrici, Alessandro; Foca, Giorgia; Ielo, Maria Cristina; Volpelli, Luisa Antonella; LO FIEGO, Domenico Pietro
abstract

Colourgrams are signals that codify the colour-related information content of a Red-Green-Blue (RGB) image, and which can be elaborated by means of proper multivariate analysis/feature selection techniques to easily identify those image features that are more useful to solve a specific problem. The reconstruction of the selected features as segmented images allows to evaluate in a critical manner the choices made automatically by the algorithm. In the present paper colourgrams are used for the detection of the red skin defect of raw hams, in order to render more objective and transferable the evaluation usually made by expert assessors. To this aim, after a preselection of 95 raw ham samples by a panel test, the corresponding RGB images were converted into colourgrams, which in turn were used to build classification models using Partial Least Squares-Discriminant Analysis (PLS-DA) and a Wavelet Packet Transform-based feature selection/classification algorithm (WPTER). Feature selection allowed to discriminate the defective samples using only three variables, with a Classification Efficiency in prediction of an external test set equal to 97.8%. The reconstruction of the samples images using only the selected features confirmed the reliability of the obtained classification model. Industrial Relevance: The evaluation of pig thighs is currently carried out by subjective methods, i.e. expert, long-trained personnel is needed to detect the presence or absence of defects. The method presented here would allow to uniform and drastically shorten the time needed for evaluation, and to avoid the main problems connected with human evaluation, i.e., subjectivity, possible unreliability, non-transferability and difficulty to collect historical data. Furthermore, it might represent a first step for setting up a comprehensive method of evaluation, aiming to take into account also other types of defects of raw hams destined to seasoning. More in general, thanks to its flexibility, this approach could be also successfully applied for the detection of other types of aspect-related features, even to monitor different kinds of products.


2012 - Drugs and precursor sensing by complementing low cost multiple techniques: overview of the European FP7 project CUSTOM [Relazione in Atti di Convegno]
Alberto, Secchi; Anna Maria, Fiorello; Massimiliano, Dispenza; Sabato, D'Auria; Antonio, Varriale; Ulrici, Alessandro; Seeber, Renato; Juho, Uotila; Vincenzo, Venditto; Paolo, Ciambelli; Juan Carlos, Antolín; Francesco, Colao; Tom, Kuusela; Ilkka, Tittonen; Päivi, Sievilä; Grégory, Maisons
abstract

A large number of techniques for drug precursors chemical sensing has been developed in the latest decades. These techniques are able to screen and identify specific molecules even at very low concentration in lab environment, nevertheless the objective to build up a system which proves to be easy to use, compact, able to provide screening over a large number of compounds and discriminate them with low false alarm rate (FA) and high probability of detection (POD) is still an open issue. The project CUSTOM, funded by the European Commission within the FP7, deals with stand alone portable sensing apparatus based on multiple techniques, integrated in a complex system with a complimentary approach. The objective of the project is to achieve an optimum trade-off between opposite requirements: compactness, simplicity, low cost, sensitivity, low false alarm rate and selectivity. The final goal is the realization of an optical sensing platform able to detect traces of drug precursors compounds, such as ephedrine, safrole, acetic anhydride and the Benzyl Methyl Keton (BMK). This is reached by implementing two main sensing techniques: the fluorescence enhanced by the use of specially developed Organic macro-molecules, and a spectroscopic technique in Mid-IR optical range. The fluorescence is highly selectivewith respect to the target compounds, because it is based on properly engineered fluorescent proteins which are able to bind the target analytes, as it happens in an 'immune-type' reaction. The spectroscopic technique is based on the Photo-Acoustic effect, enhanced by the use of a widely Tunable Quantum Cascade Laser. Finally, the sensing platform is equipped with an air sampling system including a pre-concentrator module based on a sorption desorption cycles of a syndiotactic polystyrene polymer.


2012 - Experimental design-based strategy for the simulation of complex gaseous mixture spectra to detect drug precursorsOptical Materials and Biomaterials in Security and Defence Systems Technology IX [Relazione in Atti di Convegno]
Calderisi, Marco; Ulrici, Alessandro; Pigani, Laura; Alberto, Secchi; Seeber, Renato
abstract

In the frame of the EU project CUSTOM, a new sensor system for the detection of drug precursors in gaseous samples is being developed, which also includes an External Cavity-Quantum Cascade Laser Photo Acoustic Sensor (ECQCLPAS). In order to define the characteristics of the laser source, the optimal wavenumbers within the most effective 200 cm-1 range in the mid-infrared region must be identified, in order to lead to optimal detection of the drug precursor molecules in presence of interfering species and of variable composition of the surrounding atmosphere. To this aim, based on simulations made with FT-IR spectra taken from literature, a complex multivariate analysis strategy has been developed to select the optimal wavenumbers. Firstly, the synergistic use of Experimental Design and of Signal Processing techniques led to a dataset of 5000 simulated spectra of mixtures of 33 different gases (including the 4 target molecules). After a preselection, devoted to disregard noisy regions due to small interfering molecules, the simulated mixtures were then used to select the optimal wavenumber range, by maximizing the classification efficiency, as estimated by Partial Least Squares – Discriminant Analysis. A moving window 200 cm<sup>-1</sup> wide was used for this purpose. Finally, the optimal wavenumber values were identified within the selected range, using a feature selection approach based on Genetic Algorithms and on resampling. The work made will be relatively easily turned to the spectra actually recorded with the newly developed EC-QCLPAS instrument. Furthermore, the proposed approach allows progressive adaptation of the spectral dataset to real situations, even accounting for specific, different environments.


2011 - Adulteration of the anthocyanin content of red wines: perspectives for authentication by FT-NIR and 1H NMR spectroscopies [Articolo su rivista]
Ferrari, Erika; Foca, Giorgia; M., Vignali; Tassi, Lorenzo; Ulrici, Alessandro
abstract

In the Italian oenological industry, the regular practice used to naturally increase the colour of red wines consists in blending them with a wine very rich in anthocyanins, namely Rossissimo. In the Asian market, on the other hand, anthocyanins extracted by black rice are frequently used as correctors for wine colour. This practice does not produce negative effects on health; however, in many countries, it is considered as a food adulteration. The present study is therefore aimed to discriminate wines containing anthocyanins originated from black rice and grapevine by using reliable spectroscopic techniques requiring minimum sample preparation. Two series of samples have been prepared from five original wines, that were added with different amounts of Rossissimo or of black rice anthocyanins solution, until the desired Colour Index was reached. The samples have been analysed by FT-NIR and 1H NMR spectroscopies and the resulting spectra matrices were subjected to multivariate classification. Initially, PLS-DA was used as classification method, then also variable selection/classification methods were applied, i.e. iPLS-DA and WILMA-D. The classification with variable selection of NIR spectra permitted to classify the test set samples with an efficiency of about 70%. Probably these not excellent performances are due to the matrix effect, together with the lack of sensitivity of NIR with respect to minor compounds. On the contrary, very satisfactory results were obtained on NMR spectra in the aromatic region between 6.5÷9.5 ppm. The classification method based on wavelet-based variables selection, permitted to reach an efficiency in validation greater than 95%. Finally, 2D correlation analysis was applied to FT-NIR and 1H NMR matrices, in order to recognise the spectral zones bringing the same chemical information.


2011 - An application of Z-Box method in dairy cow feedingto estimate the relationships among peNDF, otherfeed variables and productive data [Abstract in Rivista]
Gozzi, Marcello; M., Cardelli; F., Melli; Ulrici, Alessandro; Volpelli, Luisa Antonella
abstract

Physically effective NDF (peNDF) is defined as the fraction of fibrethat stimulates chewing and contributes to the floating mat oflarge particles in the rumen, and consequently to its regular activity.PeNDF is calculated from a physical effectiveness factor (pef),varying from 0 (NDF stimulates no chewing) to 1 (max chewing),which may be obtained by laboratory-based particle sizing techniques,such as Penn State Particle Separator, Mertens Separator,Z-Box, Cut Accuracy Test, based on the proportion of DM retainedon sieves (by horizontal or vertical shaking). We chose Z-Boxmethod, thanks to its easy use and applicability to as-is feed andtotal mixed rations (TMR), and we are trying to obtain an estimatingequation which may predict milk fat content and/or other productivedata from peNDF and other variables measured on TMR.To this aim, samples of TMR collected from several farms aresieved (3 sub samples each), and undergo proximate analysis,NDF, ADF, ADL and starch. Milk yield, milk fat, water addiction toTMR are collected on farm; qualitative data such as type of forage,breed, season, geographical origin and altitude (plain/hill/mountain)are also taken into account, to estimate their possible effect.As a first step, in order to investigate the complex relationshipsexisting among this wide set of variables, Principal ComponentAnalysis (PCA) is used as a data exploration tool. Two PCA models(presence of silage or not in TMR) are calculated separately. Foreach PCA model, the overall correlations among all the consideredvariables and their relative importance are investigated by meansof the loadings plots, posing particular attention to the correlationswith peNDF and with milk fat. Moreover, it is also possible to identifyhow the different groups of samples depend on specific variables.


2011 - Minimisation of instrumental noise in the acquisitionof FT-NIR spectra of bread wheat using experimental designand signal processing techniques [Articolo su rivista]
Foca, Giorgia; Ferrari, Carlotta; N., Sinelli; M., Mariotti; M., Lucisano; R., Caramanico; Ulrici, Alessandro
abstract

Spectral resolution (R) and number of repeatedscans (S) have a significant effect on the S/N ratio of Fouriertransform-near infrared (FT-NIR) spectra, but the optimalvalues of these two parameters have to be determinedempirically for a specific problem, considering separatelyboth the nature of the analysed matrix and the specificinstrumental setup. To achieve this aim, the instrumentalnoise of replicated FT-NIR spectra of wheat samples wasmodelled as a function of R and S by means of the Doehlertdesign. The noise amounts in correspondence to differentexperimental conditions were estimated by analysing thevariance signals derived from replicate measurements withtwo different signal processing tools, Savitzky–Golay (SG)filtering and fast wavelet transform (FWT), in order toseparate the “pure” instrumental noise from other variabilitysources, which are essentially connected to sample inhomogeneity.Results confirmed that R and S values leading tominimum instrumental noise can vary considerably dependingon the type of analysed food matrix and on the differentinstrumental setups, and helped in the selection of theoptimal measuring conditions for the subsequent acquisitionof a wide spectral dataset.


2011 - Modelling of Experimental Thermophysical Data by Mixing of a Ternary Solvent System [Capitolo/Saggio]
Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Thermomechanic and thermodynamic properties of mixing solvents in the liquid state have proven a powerful tool in elucidating the specific interactions and structural features supporting the liquid structure in multicomponent nonelectrolytic solutions. Mass transport properties (density, viscosity), thermophysical properties (relative permittivity, refractive index), and related thermodynamics can deepen elucidate the solvent – solvent specific interactions and behavioural peculiarities of the complex real systems. In this paper, we will primarily deal with the experimental measurements and correlative studies both on temperature and composition, of the above mentioned properties (Y), working with a ternary solvent system containing 1,2-ethanediol (ED), 2-methoxyethanol (ME) and 1,2-dimethoxyethane (DME), at various temperatures in the range -10 £ t (°C) £ 80, and with different compositions covering the whole miscibility field of the selected species. These components are strictly parent species, all being 1,2-ethanedyil-derivatives (-CH2-CH2-), pertaining to the amphiphile class molecules, with different balancing degree of hydrophobic and hydrophilic properties. Furthermore, the excess properties (YE) and deviation functions (DY) are largely stressed and examined along the text in order to identify the presence of solvent – cosolvent adducts in these ternary mixtures.


2011 - Monitoring Flour Performance in Bread Making [Capitolo/Saggio]
LI VIGNI, Mario; Baschieri, Carlo; Foca, Giorgia; Marchetti, Andrea; Ulrici, Alessandro; Cocchi, Marina
abstract

A methodology to monitor flour performance in industrial bread-making based on evaluation of rheological and chemical properties of flour, as well as near infrared (NIR) spectra, is presented. The approach considers Multivariate Control Charts for both kinds of measurements, developed on flour batches employed in production. It can be adopted at the Millers laboratories, where rheological flours properties are routinely determined, to monitor flour quality; as well as, at the Bakeries plants, where NIR spectra of every flour batch entering the production can be acquired.Moreover, the variation of protein subunits in flour batches is discussed comparatively with flours properties and bread quality. Overall, flour batches leading to lousy performance can be individuated and they also show a non-optimal protein profile.This is of particular interest from the point of view of assessing flour workability and to rationalize it in terms of flour features. Finally, NIR potentiality allows considering on-line implementation in the control of incoming raw materials.


2011 - PEDOT modified electrodes in amperometric sensing for analysis of red wine samples [Articolo su rivista]
Pigani, Laura; A., Culetu; Ulrici, Alessandro; Foca, Giorgia; M., Vignali; Seeber, Renato
abstract

A poly(3,4-ethylendioxythiophene) modified electrode has been considered as a potentially useful amperometric sensor to use either alone or in the frame of a set of sensors bearing complementary information, i.e. within an electronic tongue. The sensor is proposed in blind analysis of red wines, for classificationand calibration purposes. The data obtained from voltammetric measurements have been treated using partial least squares analysis. A calibration procedure has been performed to correlate results from analyses of wines, executed with traditional analytical methods, with the corresponding voltammetricresponses. Moreover, classification models of the wine samples, based on quantitative parameters and qualitative information about origin and variety, have been built. The developed electrochemical sensor also allows the fast identification of samples exceeding threshold limits of meaningful parameters forquality control in the wine industry, such as SO2, colour intensity and total polyphenols. The application of the system within a sensor array (electronic tongue) to fast pre-screening routine control procedure is proposed.


2011 - Prediction of compositional and sensory characteristics using RGB digital images and multivariate calibration techniques [Articolo su rivista]
Foca, Giorgia; Masino, Francesca; Antonelli, Andrea; Ulrici, Alessandro
abstract

In the present paper, the possibility to use the information contained in RGB digital images to gain a fast and inexpensive quantification of colour-related properties of food is explored. To this aim, we present an approach which consists, as first step, in condensing the colour related information contained in RGB digital images of the analysed samples in one-dimensional signals, named colourgrams. These signals are then used as descriptor variables in multivariate calibration models. The feasibility of this approach has been tested using as a benchmark a series of samples of pesto sauce, whose RGB images have been used to predict both visual attributes defined by a panel test and the content of various pigments (chlorophylls a and b, pheophytins a and b, b-carotene and lutein).The possibility to predict correctly the values of some of the studied parameters suggests the feasibility of this approach for fast monitoring of the main aspect-related properties of a food matrix. The values of the squared correlation coefficient computed in prediction on a test set (R2Pred) for green and yellow hues were greater than 0.75, while R2Pred values greater than 0.85 were obtained for the prediction of total chlorophylls content and of chlorophylls/pheophytins ratio. The great flexibility of this blind analysis method for the quantitative evaluation of colour related features of matrices with an inhomogeneous aspect suggests that it is possible to implement automated, objective, and transferable systems for fast monitoring of raw materials, different stages of the manufacture and end products, not necessarily for the food industry only.


2011 - Seeds of Horse Chestnut (Aesculus hippocastanum L.) and Their Possible Utilization for Human Consumption [Capitolo/Saggio]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina; Durante, Caterina; LI VIGNI, Mario; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo
abstract

This chapter appraises the seeds of horse chestnuts (. Aesculus hippocastanum [AH]) and their derived products. Escin, the major bioactive principle in AH seeds, has shown satisfactory evidence of clinically significant activity in the treatment of chronic venous insufficiency, hemorrhoids, postoperative edema, and mammary induration. There is some evidence that various escin molecules, such as saponins and sapogenins, show beneficial effects when administered at the right concentration, exhibiting an ethanol absorption inhibitory effect and hypoglycemic activity in the oral glucose tolerance test in vivo. Horse chestnut extract has a higher antioxidant activity than vitamin E, showing one of the highest "active-oxygen" scavenging abilities compared to other natural products. β-Escin from AH extracts was also tested to evaluate the chemopreventive efficacy of its dietary intake on azoxymethane-induced colonic aberrant crypt foci. The main adverse effects of escins in humans are due to their hemolytic activity. Research efforts in this field are devoted to improving the selectivity for aberrant red corpuscles, promoting the β-escin fraction as a useful candidate agent for exploring new potential antileukemic drugs. Fresh or naturally desiccated seeds are usually treated by long leaching with water or wooden ashes to remove harshness and bitterness. These treatments cause a variation in the molecular structures of escin fractions, reducing the toxicity but maintaining their nutraceutical potential and anti-obesity effects. Alternatively, the slow roasting of nuts makes the escins harmless and the seeds edible. The claimed toxicity of these extracts makes them natural antibacterials, antimicrobials, antivirals, and antifungals, to some extent, that also act as environmentally biocompatible phytotherapeutics.


2010 - Applicazione della spettroscopia FT-NIR per la classificazione tecnologica del frumento tenero: Parte I [Relazione in Atti di Convegno]
N., Sinelli; M., Mariotti; M., Lucisano; Foca, Giorgia; Ulrici, Alessandro
abstract

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2010 - Applicazione della spettroscopia FT-NIR per la classificazione tecnologica del frumento tenero: Parte II [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; C., Ferrari; N., Sinelli; M., Mariotti; R., Caramanico
abstract

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2010 - Wheat flour formulation by mixture design and multivariate study of its technological properties [Articolo su rivista]
LI VIGNI, Mario; Durante, Caterina; Foca, Giorgia; Ulrici, Alessandro; Birthe Pontoppidan Møller, Jespersen; Rasmus, Bro; Cocchi, Marina
abstract

Wheat flour plays a pivotal role in determining the overall quality of bread (loaf dimensions, crumb texture and consistency). A precise knowledge of flour chemical and technological properties is of paramount importance for the baking industry, to tune the modifications of the recipe and production parameters. However, it is still common to have to deal with an empirical, trial and error-based approach, and generally, time consuming techniques are employed to determine the quality indexes for flour.In the context of an industrial bread-making process, this study addresses the evaluation of the effect of a systematic variation in the mixture composition of wheat flours on their properties. The main objective is to offer this field a more rigorous method to evaluate and improve flour properties, by employing experimental design methodologies and interpreting the results in a multivariate way, instead of the common one variable at a time approach. The results show that a careful planning of flour mixtures when testing new varieties and formulation helps to obtain meaningful and easy-to-understand results as far as their properties are concerned.


2009 - Application of signal processing and experimental design techniques for the minimisation of instrumental noise in the acquisition of FT-NIR spectra of bread wheat samples [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; N., Sinelli; M., Mariotti; LI VIGNI, Mario; Cocchi, Marina; P., Belloni
abstract

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2009 - Classification of NMR spectra collected on wines added with anthocyanins from grape and black rice [Relazione in Atti di Convegno]
Foca, Giorgia; Ferrari, Erika; M., Vignali; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2009 - Classification of Red Wines by Chemometric Analysis of Voltammetric Signals from Pedot-Modified Electrodes. [Articolo su rivista]
Pigani, Laura; Foca, Giorgia; Ulrici, Alessandro; K., Ionescu; V., Martina; Terzi, Fabio; M., Vignali; Zanardi, Chiara; Seeber, Renato
abstract

Nine different types of Italian red wines of four different varieties were analysed, without any samplepre-treatments, by voltammetric techniques using a poly(3,4-ethylenedioxythiophene)-modified electrode.The data matrices consisting of the currents measured at different potentials, by repeated CyclicVoltammetry or Differential Pulse Voltammetry, are submitted to chemometric analysis. After explorativetests based on Principal Component Analysis, Partial Least Squares-Discriminant Analysis classificationmodels are built both for the training and for the test sets. To this aim, different classification strategiesare adopted, considering the responses from the two techniques either separately or joined together toform a data matrix including the whole voltammetric information.


2009 - Colorigrammi: impiego di fotocamere digitali come sensori ottici per l’analisi del colore di matrici alimentari disomogenee [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia
abstract

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2009 - Different Feature Selection Strategies in the Wavelet Domain applied to NIR-Based Quality Classification Models of Bread Wheat Flours [Articolo su rivista]
Foca, Giorgia; Cocchi, Marina; LI VIGNI, Mario; R., Caramanico; M., Corbellini; Ulrici, Alessandro
abstract

The Synthetic Quality Index method (Indice Sintetico di Qualità, ISQ) is used in the Italian cereal trade context for the classification of bread wheat in different quality categories, and consists in the assignation by an expert assessor of each wheat sample to the most fitting class, on the basis of parameters reflecting chemical and rheological properties of the flour. The high uncertainty of this procedure has been recently proved by some of us using a panel test, which confirmed a quite large degree of subjectivity in the assignation of samples to the quality classes.However, the results obtained with the panel test allowed to identify samples whose class assignation is sufficiently univocal, to be used for the development of automated classification methods based on NIR spectra. In the present work, multivariate classification models have been calculated using the WPTER algorithm, which aims at selecting — among the wavelet coefficients derived by application of the Wavelet Packet Transform to the analysed NIR spectra — only those features leading to the best possible discrimination among the considered classes. In particular, WPTER has been used following three different strategies to choose the optimal conditions for the development of SIMCA class models. Due to the restricted number of objects, the statistical validity of the models has been evaluated using a newly developed algorithm, which performs a double cross-validation of the SIMCA models, and by comparison with the results obtained by permutation tests.


2009 - Dohelert experimental design and signal processing techniques applied to the minimization of instrumental noise in FT-NIR spectra of wheat samples [Relazione in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; N., Sinelli; M., Mariotti
abstract

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2009 - Hyperspectral image analysis for bread characterization in the baking industry [Relazione in Atti di Convegno]
LI VIGNI, Mario; J., Manuel Amigo; Ulrici, Alessandro; Foca, Giorgia; Cocchi, Marina; R., Bro; B. P., Møller Jespersen
abstract

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2009 - Mid and Near Infrared Spectroscopy to analyse surface defectiveness in bread [Relazione in Atti di Convegno]
Foca, Giorgia; LI VIGNI, Mario; Ulrici, Alessandro; Cocchi, Marina
abstract

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2009 - Minimisation of instrumental noise in the acquisition of FT-NIR spectra by means of Doehlert design and signal processing techniques [Relazione in Atti di Convegno]
Foca, Giorgia; Ferrari, Carlotta; N., Sinelli; M., Mariotti; Ulrici, Alessandro
abstract

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2009 - Near Infrared Spectroscopy and Multivariate Analysis methods for monitoring flour performance in an industrial bread-making process [Articolo su rivista]
LI VIGNI, Mario; DURANTE, Caterina; FOCA, Giorgia; MARCHETTI, Andrea; ULRICI, Alessandro; COCCHI, Marina
abstract

The present study is aimed at evaluating the possibility to predict bread specifications, for an industrial bread-making process, on the basis of the properties of flour employed in production. The flour delivered at the production plant, of which rheological and chemical properties were available, were analysed by means of Near Infrared Spectroscopy (NIRS). Based on the flour properties and NIR signals, multivariate control charts were constructed in order to detect flour batches leading to a bread with non-optimal behaviour. The results show that it is possible to distinguish flour batches leading to a product with a particularly negative performance, by modelling the properties commonly measured on flours and the acquired Near Infrared signals. In spite of the absence of monitoring of process variables, which could have offered a more sound basis for the interpretation, especially when false positives and negatives are detected, these results are of particular interest from the point of view of raw material evaluation in process monitoring. Also, the potentiality of Near Infrared Spectroscopy allows considering this approach for an on-line implementation in the control of incoming raw materials in this industrial process.


2009 - Study of protein content of wheat flour in relation to technological properties using chromatography, NIRS and chemometrics [Relazione in Atti di Convegno]
Baschieri, Carlo; LI VIGNI, Mario; Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Ulrici, Alessandro
abstract

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2009 - Wheat Flour formulation by Mixture Design and study of its properties and performance [Relazione in Atti di Convegno]
LI VIGNI, Mario; Cocchi, Marina; Durante, Caterina; Ulrici, Alessandro; Foca, Giorgia; R., Bro; B. P., Møller Jespersen
abstract

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2008 - A chemometric study of pesto sauce appearance and of its relation to pigment concentration [Articolo su rivista]
Masino, Francesca; Foca, Giorgia; Ulrici, Alessandro; Arru, Laura; Antonelli, Andrea
abstract

Pesto sauce is a typical example of a food matrix in which aspect is of key importance to the final judgment of the consumer, and whose color strongly depends on the production process and on the ingredients. In view of this, the aim of the present work is to evaluate the possibility of quantifying the variability of visual aspect of different brands of pesto sauce, and its relation to the concentration of the main pigments. Sensory evaluation of the appearance of 12 commercial pesto samples was carried out by a panel of 16 assessors who evaluated quantitatively six visual attributes, suitably defined for the description of pesto aspect. A quantitative estimate of the performance of the panel was carried out by means of both univariate and multivariate–multiway chemometric tools (parallel factor analysis, PARAFAC). In addition, the relationship between the mean sensory scores values and the concentrations of chlorophylls, pheophytins and carotenoids was investigated by principal components analysis (PCA). Both PCA and PARAFAC showed good clustering of thesamples and a satisfactory degree of homogeneity of the assessors. Data analysis showed that assessors fundamentally agree about the main visual characteristics of pesto sauces, which are partly correlated with the concentration values of the main pigments.


2008 - Amperometric sensors based on poly(3,4-ethylenedioxythiophene)-modified electrodes: Discrimination of white wines [Articolo su rivista]
Pigani, Laura; Foca, Giorgia; K., Ionescu; Martina, Virginia; Ulrici, Alessandro; Terzi, Fabio; M., Vignali; Zanardi, Chiara; Seeber, Renato
abstract

The voltammetric responses on selected white wines of different vintages and origins havebeen systematically collected by three different modified electrodes, in order to check theireffectiveness in performing blind analysis of similar matrices. The electrode modifiers consistof a conducting polymer, namely poly(3,4-ethylenedioxythiophene) (PEDOT) and of compositematerials of Au and Pt nanoparticles embedded in a PEDOT layer. Wine samples havebeen tested, without any prior treatments, with differential pulse voltammetry technique.The subsequent chemometric analysis has been carried out both separately on the signals ofeach sensor, and on the signals of two or even three sensors as a unique set of data, in order tocheck the possible complementarity of the information brought by the different electrodes.After a preliminary inspection by principal component analysis, classification models havebeen built and validated by partial least squares-discriminant analysis. The discriminantcapability has been evaluated in terms of sensitivity and specificity of classification; in allcases quite good results have been obtained.


2008 - At-line control of an industrial bread-making process [Abstract in Atti di Convegno]
LI VIGNI, Mario; Brettagna, B; Cocchi, Marina; DE MARCO, T; Foca, Giorgia; Marchetti, Andrea; Ulrici, Alessandro
abstract

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2008 - At-line monitoring of the leavening process in industrial bread making by near infrared spectroscopy [Articolo su rivista]
Ulrici, Alessandro; LI VIGNI, Mario; Durante, Caterina; Foca, Giorgia; P., Belloni; B., Brettagna; T., DE MARCO; Cocchi, Marina
abstract

The potential of near infrared (NIR) spectroscopy to characterise doughs for industrial bread making, directly at the production plant, was investigated. Different stages of dough processing have been monitored at-line, employing a Fourier transform-NIR instrument equipped with an optical fi bre. Parallel factors analysis has been used to study the spectral variation throughout the production line, with the aim of acquiring indications on the modifi cations the dough undergoes during the process. Moreover, wavelet interface for linear modelling analysis, which performs variable selection in the wavelet domain, has been employed to explore the possibility of monitoring the leavening step by identifying a relationship between the NIR signal and the leavening phase, considering the leavening time and the total titrable acidity of the dough. Results show that some aspects of the leavening process can be calibrated from the NIR spectra, thus corroborating the fact that the NIR signal is infl uenced by the modifi cations that occur along with the production process.


2008 - Caratterizzazione di vini addizionati di antociani di diversa origine mediante spettroscopia NIR e analisi chemiometrica dei segnali [Abstract in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Tassi, Lorenzo; Vignali, M.
abstract

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2008 - Classificazione multivariata di spettri NIR di vini addizionati di antociani provenienti da uva e da riso nero [Abstract in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Tassi, Lorenzo; Vignali, M.
abstract

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2008 - Controllo di un processo industriale di panificazione mediante NIRS ed analisi multivariata [Abstract in Atti di Convegno]
LI VIGNI, Mario; Brettagna, B; Cocchi, Marina; DE MARCO, T; Foca, Giorgia; Marchetti, Andrea; Ulrici, Alessandro; Quaglia, L.
abstract

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2008 - Extraction and quantification of main pigments in pesto sauces [Articolo su rivista]
Masino, Francesca; Ulrici, Alessandro; Antonelli, Andrea
abstract

Pesto is a widely diffused Italian pasta sauce, whose main ingredient is basil. Since its appearance is a key factor for marketing, the determination of its pigment content is of fundamental interest. To this aim, a method for the determination of pesto pigments by C18-HPLC is proposed. Only b-carotene was determined directly by Vis-spectrophotometry, as a consequenceof sample purification over a silica cartridge.The proposed method is reliable allowing, for the first time, an easy determination of chlorophylls, pheophytins, lutein and b-carotene in a complex matrix such as pesto. The results show great differences in pigment composition among the samples, with pheophytins as the main components. Only non-thermally processed product show appreciable chlorophyll content as aconsequence of the different production technique.Principal Component Analysis performed on thepigment contents showed great variability among thedifferent samples.


2008 - Metodi rapidi di valutazione qualitativa del frumento tenero [Articolo su rivista]
Foca, Giorgia; Ulrici, Alessandro; M., Corbellini; R., Caramanico; M., Lucisano; M. A., Pagani; Cocchi, Marina; Tassi, Lorenzo; G., Boggini
abstract

SommarioNella classificazione di frumenti teneri mediante il metodo ISQ (Indice Sintetico di Qualità), un valutatore esperto classifica ogni campione di grano in diverse categorie qualitative, definite in base ad alcuni parametri chimici e reologici. Le analisi impiegate per la determinazione di tali parametri richiedono lunghi tempi di esecuzione e l’impiego di personale esperto, mentre durante le transazioni commerciali i prodotti devono essere caratterizzati in tempi molto brevi. Per questa ragione, è stato sviluppato un metodo veloce ed automatizzato per la classificazione del frumento, basato sull’accoppiamento della spettroscopia nel vicino infrarosso (NIR) con metodi di analisi multivariata dei dati.SummaryDuring the classification of bread wheats by means of the ISQ method (Synthetic Index of Quality), an expert assessor classifies each wheat sample in different quality categories, defined on the basis of some chemical and rheological parameters. The analyses involved in the determination of such parameters require long times of execution and the employing of skilled personnel, whereas, during the commercial transactions, the products need to be characterized in very short times. For this reason, we developed a fast and automated method of wheat classification based on the coupling of the Near InfraRed spectroscopy (NIR) and multivariate data analysis methods.


2008 - Modelling of Experimental Thermophysical Data by Mixing of a Ternary Solvent System, in Solution Chemistry [Capitolo/Saggio]
Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Thermomechanic and thermodynamic properties of mixing solvents in the liquid state have proven a powerful tool in elucidating the specific interactions and structural features supporting the liquid structure in multicomponent nonelectrolytic solutions. Mass transport properties (density, viscosity), thermophysical properties (relative permittivity, refractive index), and related thermodynamics can deepen elucidate the solvent – solvent specific interactions and behavioural peculiarities of the complex real systems. In this paper, we will primarily deal with the experimental measurements and correlative studies both on temperature and composition, of the above mentioned properties (Y), working with a ternary solvent system containing 1,2-ethanediol (ED), 2-methoxyethanol (ME) and 1,2-dimethoxyethane (DME), at various temperatures in the range -10 £ t (°C) £ 80, and with different compositions covering the whole miscibility field of the selected species. These components are strictly parent species, all being 1,2-ethanedyil-derivatives (-CH2-CH2-), pertaining to the amphiphile class molecules, with different balancing degree of hydrophobic and hydrophilic properties. Furthermore, the excess properties (YE) and deviation functions (DY) are largely stressed and examined along the text in order to identify the presence of solvent – cosolvent adducts in these ternary mixtures.


2008 - Multicomponent analysis in the wavelet domain of highly overlapped electrochemical signals: resolution of quaternary mixtures of chlorophenols using a peg-modified sonogel-carbon electrode [Articolo su rivista]
J. M., PALACIOS SANTANDER; L. M., CUBILLANA AGUILERA; Cocchi, Marina; Ulrici, Alessandro; I., NARANJO RODRÍGUEZ; Seeber, Renato; J. L., HIDALGO HIDALGO DE CISNEROS
abstract

Chemometricmethods have been applied to resolve mixture of phenols; phenolic compounds are amongst themost interesting chemical species from an environmental viewpoint.However, the number of papers that applymultivariate calibration methods to resolve electroanalytical signals of mixture of phenols is low.In this paper, we propose a new chemometric methodology to resolve, in the wavelet domain, quaternary mixtures of chlorophenols: 4-chloro-3-methylphenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol, in a concentration range from 0.05 to 0.25 mg·L−1, using differential pulse adsorptive stripping voltammetry (DPAdSV) as the electrochemical technique, and a new polyethylenglycol-modified Sonogel–Carbon electrode.The results obtained after applying a FastWavelet Transform (FWT)-based feature selection algorithm, coupled with different multivariate calibration methods (multilinear regression-MLR and partial least squares regression-PLS) are compared with those obtained from a direct PLS. Besides, an Orthogonal Signal Correction (OSC)-based Calibration Transfer procedure (OSC-CT) is also applied, as a pre-processing tool, in order to improve the results obtained with the previous techniques.


2008 - Multivariate analysis of analytical signals to decipher relevant chemical information [Capitolo/Saggio]
Ulrici, Alessandro; Cocchi, Marina; Durante, Caterina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo
abstract

Two main elements have recently characterized the research in the analytical field: on one hand the huge development of instrumental analysis in the direction of hyphenated techniques and, on the other hand, the huge development and decreasing cost of computers together with the increased capacity of computational tools. Moreover, new issues are presented to the analytical researcher by new regulations that impose to demonstrate that the whole process is under control, e.g. in the industrial/productive context, or in the life science context by the emerging need of systems biology. Thus, the role of chemometrics is more and more increasing and the toolbox of chemometrics-like methods has been progressively enriched.In particular, deciphering signal-fingerprinting of complex matrix samples requires a deeper consideration on the nature of signals feature, and it has to be taken into account that the information pertinent to the problem is mixed with many uninformative sources of variations that may affect part or the whole signal domain. These issues from the data analysis point of view are reflected in a greater complexity of the preprocessing/pretreatment and variable selection steps.The main focus of this chapter will be on feature selection methodology; after a concise review of the main recently proposed feature selection methods, the specific case of feature selection in the wavelet (WT) domain will then be considered. In particular, it will deal with illustration of our recent developed tools for WT-feature selection in regression and classification tasks. The discussion of different applications will be the core of the work, to illustrate the effectiveness of the integration of both basic (simple) and more advanced methodologies together, with a complete strategy embracing data exploration, modelling, data display-interpretation and validation.


2007 - Caratterizzazione del Nocino tipico emiliano mediante indagini chimico-fisiche ed analisi chemiometriche [Relazione in Atti di Convegno]
Foca, Giorgia; Franchini, Giancarlo; Grandi, Margherita; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2007 - Caratterizzazione spettroscopica e tecnologica di miscele gluten-free formulate mediante disegno sperimentale [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Cocchi, Marina; LI VIGNI, Mario; PAGANI M., A; Lucisano, M.
abstract

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2007 - Characterisation and optimisation of gluten-free formulations by multivariate analysis of technological parameters and nir spectra collected on d-optimal designed mixtures [Relazione in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina; PAGANI M., A; Lucisano, M.
abstract

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2007 - Chemical composition and characterisation of seeds from two varieties (pure and hybrid) of Aesculus hippocastanum [Articolo su rivista]
Baraldi, Cecilia; Bodecchi, Lidia Maria; Cocchi, Marina; Durante, Caterina; Ferrari, Giorgia; Foca, Giorgia; Grandi, Margherita; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Investigations have been conducted on some samples of naturally desiccated horse-chestnuts (Aesculus hippocastanum), representativeof the two most common mediterranean varieties: the pure species (AHP, giving white flowers), and a hybrid (AHH, giving pink flowers).Different experimental techniques have been used to gain more information on morphological structure and chemical composition ofthese complex matrices. Surface analysis by SEM showed no differences in such floured samples (wild type), while thermal behaviour(DSC) outlines some significant differences between them. Chemical composition reveals some differences in residual moisture(AHP = 6.97%; AHH = 6.59%), proteins (AHP = 2.64%; AHH = 1.82%), lipids (AHP = 4.13%; AHH = 5.10%), glucides (AHP =15.2%; AHH = 14.3%), and ashes (AHP = 2.51%; AHH = 2.19%). Most likely, these characters modulate other undifferentiated chemicalparameters, such as cold water solubility (CWS:AHP = 53.9%; AHH = 48.6%), and total inorganic soluble salts (TISS:AHP = 2.18%; AHH = 1.92%). Principal component analysis was applied to differentiate the two horse-chestnuts varieties. In particular,the first principal component effectively distinguish and discriminates AHH and AHP samples in two well-separated categories, giving, atthe same time, some information on the influence of the whole set of chemical compositional parameters.


2007 - Colourgrams: an alternative, fast and inexpensive way for characterising inhomogeneous food matrices through multivariate image analysis [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia
abstract

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2007 - Determinazione di acidi e zuccheri presenti negli impasti per la produzione industriale di pane a diversi stadi della lavorazione [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; LI VIGNI, Mario; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2007 - Development of an electronic tongue based on a PEDOT-modified voltammetric sensor [Articolo su rivista]
V., Martina; K., Ionescu; PIGANI, Laura; TERZI, Fabio; ULRICI, Alessandro; ZANARDI, Chiara; SEEBER, Renato
abstract

Three different electrodes were tested for use as nonspecific amperometric sensors for blind analysis on real matrices, namely different fruit juices from different fruits or different brands. The first two electrodes were traditional Pt and Au electrodes, while the third one was modified with poly(3,4-ethylenedioxythiophene) conducting polymer. The sensors were tested separately, tested coupled to each other, and also tested together. The responses of the electrode system(s) were first screened via PCA and then their discriminant capabilities were quantified in terms of the sensitivities and specificities of their corresponding PLS-DA multivariate classification models. Particular attention was paid to analyzing the evolution of the response over subsequent potential sweeps. The modified electrode demonstrated the most discriminating ability, and it was the only system capable of satisfactorily performing the most complex task attempted during the analysis: discriminating between juices from the same fruit but from different brands. Moreover, the electrode cleaning procedure required between two subsequent potential sweeps was much simpler for the modified electrode than for the others. This electrode system was therefore shown to be a good candidate for use as an informative element in an electronic tongue applied to the analysis of other food matrices.


2007 - Efficient variables selection in multivariate analysis of signals by coupling fast wavelet transform and genetic algorithms [Relazione in Atti di Convegno]
Cocchi, Marina; Durante, Caterina; Foca, Giorgia; LI VIGNI, Mario; Leardi, R; Ulrici, Alessandro
abstract

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2007 - Elaboration and Application of Algorithms Performing Feature Selection in the Wavelet Domain for Analysis of NIR based data [Relazione in Atti di Convegno]
Cocchi, Marina; Durante, Caterina; LI VIGNI, Mario; Foca, Giorgia; Ulrici, Alessandro
abstract

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2007 - End-use classification of wheat flours after feature selection on NIR spectra [Relazione in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina; Corbellini, M; Tassi, Lorenzo
abstract

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2007 - Monitoraggio multivariato di un processo industriale di panificazione [Relazione in Atti di Convegno]
Belloni, P; Brettagna, B; Cocchi, Marina; DE MARCO, T; Foca, Giorgia; LI VIGNI, Mario; Marchetti, Andrea; Ulrici, Alessandro
abstract

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2007 - Monitoring an industrial bread making process by means of Near Infrared Spectroscopy and chemometric methods [Relazione in Atti di Convegno]
P., Belloni; B., Brettagna; Cocchi, Marina; T., De Marco; Durante, Caterina; Foca, Giorgia; LI VIGNI, Mario; Marchetti, Andrea; Ulrici, Alessandro
abstract

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2007 - Monitoring of the leavening process in industrial bread making [Relazione in Atti di Convegno]
Belloni, P; Brettagna, B; Cocchi, Marina; DE MARCO, T; Foca, Giorgia; LI VIGNI, Mario; Marchetti, Andrea; Ulrici, Alessandro
abstract

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2007 - Multivariate analysis of NIR spectra collected on D-optimal designed gluten-free doughs [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Cocchi, Marina; PAGANI M., A; Lucisano, M.
abstract

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2007 - Preliminary investigation of the use of digital image analysis for raw ham evaluation [Articolo su rivista]
LO FIEGO, Domenico Pietro; Comellini, Michele; Ielo, Maria Cristina; Ulrici, Alessandro; Volpelli, Luisa Antonella; F., Tassone; L., Nanni Costa
abstract

In order to find objective parameters for the evaluation of pig thighs to be used for PDO processing, digital images of the external surface of 384 left thighs were acquired, to be used for multivariate image analysis. The following parameters were also measured on the same samples: weight, length, circumference, thickness of fat and thigh, globosity index and colour of skin. Moreover, a subjective evaluation of veining and red skin defects was also made by an expert assessor. Multivariate analysis of the digital images showed a separation of the analysed samples in two clusters, whose differences were then investigated on the basis of the other traits. Various differences between the two clusters where found, mainly for the size-related parameters.


2007 - Reproducibility evaluation of classification by expert assessors of raw ham red skin defect [Relazione in Atti di Convegno]
LO FIEGO, Domenico Pietro; Ulrici, Alessandro; Ielo, Maria Cristina; Comellini, Michele; F., Tassone; L., Nanni Costa
abstract

The evaluation of qualitative characteristics of fresh pig thighs to be used for seasoning is generally made by expert assessors basing on visual aspect. To estimate quantitatively the degree of objectivity of human evaluation of visual aspect, digital images were acquired on a series of raw ham samples and then subjected to the classification by expert assessors in three quality categories related to the red skin defect. The results obtained from the panel have been analysed in terms of Validity (correctness of the response) and Reliability (ability of the assessor to reproduce his own results). Moreover, also the percentage of assignations of each sample to the correct class was estimated. The results suggest that the proposed approach can be used both to monitor the reliability of the single assessors, and to identify samples whose class assignation is reasonably indubitable.


2007 - Reproducibility of the Italian ISQ method for quality classification of bread wheats: An evaluation by expert assessors [Articolo su rivista]
Foca, Giorgia; Ulrici, Alessandro; M., Corbellini; Ma, Pagani; M., Lucisano; Franchini, Giancarlo; Tassi, Lorenzo
abstract

The great variety of different bakery products in Italy has led to the development of a method, the Synthetic Index of Quality (Indice Sintetico, di Qualita, ISQ), for the classification of bread wheats in different quality categories. Based on chemical and rheological properties, each wheat sample is assigned to the most suitable class by an expert assessor. In many cases this procedure is not straightforward, making the class assignation uncertain, thus leading to the possibility of controversies during the trading phase. In the present study, in order to have a quantitative estimate of the validity and reliability of this procedure, a panel composed of nine expert assessors was utilised for the repeated evaluation of 100 samples of bread wheats of various qualities. The results suggest that the proposed approach can be used both to monitor the reliability of the single assessors, and to identify samples whose class assignation is reasonably indubitable, e.g. to be used for the development of automated classification methods. Moreover, the analysis of the most uncertain assignation cases can be useful in order to enhance the ISQ classification method itself. (c) 2007 Society of Chemical Industry.


2006 - Analysis of Sensory data of Aceto Balsamico Tradizionale di Modena (ABTM) of different ageing by application of PARAFAC models. [Articolo su rivista]
Cocchi, Marina; R., Bro; Durante, Caterina; Manzini, Daniela; Marchetti, Andrea; F., Saccani; Sighinolfi, Simona; Ulrici, Alessandro
abstract

Aceto Balsamico Tradizionale di Modena is a typical Italian food product of protected denomination of origin, obtained by alco- holic fermentation and acetic bio-oxidation of cooked musts, and it is aged for at least 12 years in series of wooden casks. The prod- uct suitable for marketing is qualified by sensory examination on the whole of 13 sensory parameters. In this study, a series of six casks for each of seven different producers have been investigated by an expert Panel of eight judges, aiming at (i) assessing the degree of variability of the different sensorial attributes with samples ageing, and (ii) evaluating the sim- ilarity/dissimilarity among the various parameters together with the degree of agreement of the panellists. Given the three-way nature of the data (samples · panellists · sensory attributes) the PARAFAC method has been used, and a satisfactory model was obtained, highlighting the efficacy of three-way analysis in dealing with the different sources of data variabil- ity, extracting the relevant information and displaying it in a simple and interpretable manner.


2006 - Applicazione di algoritmi per la selezione di variabili nell’analisi di spettri NIR di prodotti alimentari [Relazione in Atti di Convegno]
Cocchi, Marina; Ulrici, Alessandro; Foca, Giorgia; Durante, Caterina
abstract

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2006 - Classificazione chemiometrica di spettri NIR di frammenti ossei di specie animali diverse [Relazione in Atti di Convegno]
Cocchi, Marina; Pavino, D; Ulrici, Alessandro; Foca, Giorgia; Durante, Caterina; Martra, G; Abete, M. C.
abstract

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2006 - Classificazione multivariata sulla base di spettri NIR dei risultati di un panel test per il riconoscimento della classe qualitativa del grano tenero [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Cocchi, Marina; Corbellini, M; Franchini, Giancarlo; Tassi, Lorenzo
abstract

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2006 - Controllo at-line di impasti per la produzione industriale di pane mediante tecniche analitiche e chemiometriche [Relazione in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina; Marchetti, Andrea; LI VIGNI, Mario
abstract

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2006 - Determinazione di pigmenti e attributi sensoriali mediante analisi multivariata del colore di immagini digitali [Abstract in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Masino, Francesca
abstract

Recentemente è stato presentato un nuovo metodo automatizzato per la classificazione di matrici alimentari disomogenee sulla base delle comuni fotografie digitali RGB che, rappresentando il contenuto in colore di ogni immagine digitale sotto forma di un segnale (colorigramma) dato dalla sequenza di curve di distribuzione di vari descrittori del colore dei pixel, permette di selezionare le regioni più significative con opportuni algoritmi di feature selection/classificazione. I risultati ottenuti su una serie di campioni di pesto alla genovese, ci hanno spinto a valutare la possibilità di impiegare lo stesso approccio a scopi di calibrazione, utilizzando i colorigrammi ottenuti da fotografie di campioni di pesto per prevederne il contenuto in pigmenti (clorofille, feofitine, caroteni) ed alcune caratteristiche legate all’aspetto, valutate per mezzo di un panel test. Per molte delle proprietà studiate sono stati ottenuti modelli di calibrazione PLS con soddisfacente capacità predittiva, e risultati ancora migliori sono stati raggiunti impiegando un algoritmo di feature selection/calibrazione basato sulla Trasformata Wavelet.


2006 - Durum wheat adulteration detection by NIR spectroscopy multivariate calibration [Articolo su rivista]
COCCHI, Marina; DURANTE, Caterina; FOCA, Giorgia; MARCHETTI, Andrea; TASSI, Lorenzo; ULRICI, Alessandro
abstract

In the present work, we explored the possibility of using near-infrared spectroscopy in order to quantify the degree of adulteration of durum wheat flour with common bread wheat flour. The multivariate calibration techniques adopted to this aim were PLS and a wavelet-based calibration algorithm, recently developed by some of us, called WILMA. Both techniques provided satisfactory results, the percentage of adulterant present in the samples being quantified with an uncertainty lower than that associated to the Italian official method. In particular the WILMA algorithm, by performing feature selection, allowed the signal pretreatment to be avoided and obtaining more parsimonious models.


2006 - Elaboration and Application of Algorithms Performing Feature Selection in the Wavelet Domain [Relazione in Atti di Convegno]
Ulrici, Alessandro; Cocchi, Marina; Foca, Giorgia
abstract

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2006 - Feature selection e classificazione multivariata nel dominio wavelet per la classificazione di spettri NIR di grani di diversa qualità [Relazione in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina
abstract

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2006 - Monitoraggio at-line del processo di lievitazione di impasti per la produzione industriale di pane [Relazione in Atti di Convegno]
Ulrici, Alessandro; Cocchi, Marina; Marchetti, Andrea; Foca, Giorgia; Durante, Caterina; DE MARCO, T; Brettagna, B; Belloni, P.
abstract

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2006 - Study of the dependence on temperature and composition of the volumic properties of ethane-1,2-diol+2-methoxyethanol+1,2-dimethoxyethane plus water solvent system and graphical representation in the quaternary domain [Articolo su rivista]
Ulrici, Alessandro; Cocchi, Marina; Foca, Giorgia; M., Manfredini; Marchetti, Andrea; D., Manzini; Tassi, Lorenzo; S., Sighinolfi
abstract

In this paper, the temperature and composition dependencies of the volumetric behavior are studied for the ethane-1,2-diol + 2-methoxyethanol + 1,2-dimethoxyethane + water quaternary system. Density data were collected at different temperatures ranging from -10 to 80 degrees C and at atmospheric pressure over the whole composition range, 0 :5 x(i)(i = 1, 2, 3,4) <= 1. Moreover, we also made use of the results on the six binary (ij) and four ternary (kij) subsystems studied previously. The excess molar volume (V-E) data have been fitted to an equation derived from the well-known Redlich-Kister equation and some interesting correlations were found. Furthermore, in order to represent in an effective way the behavior of the V-E = V-E(x(i)) function (and of the derived partial molar quantities) in the quaternary domain, a new algorithm has been developed, which gives 3D plots where the dependent function is depicted by means of '' colored slices '' of the tetrahedron corresponding to the investigated composition quaternary domain.


2005 - A study of the relationships among acidity, sugar and furanic compound concentrations in set of casks for Aceto Balsamico Tradizionale of Reggio Emilia by means of multivariate techniques [Articolo su rivista]
Masino, Francesca; F., Chinnici; Franchini, Giancarlo; Ulrici, Alessandro; Antonelli, Andrea
abstract

‘‘Aceto Balsamico Tradizionale’’ (ABT) is gaining increasing attention due to its peculiar characteristics, not only within the production area. A first approach to understanding the complex ageing process was performed by studying ABT furanic compounds, quantified by HPLC: hydroxymethylfurfural, furoic acid, furfural, and 5-acetoxymethylfurfural (HMF, FA, Fal, AMFA). Also, other parameters, expressing the acidic and sugar contents (pH, total acidity and Brix), were quantified.Furanic compounds arise during the must concentration process. Moreover, they tend to rise on ageing, as a consequence of thewater loss during the process. However, due to the great reactivity of these substances, which rapidly evolve into other compounds, differences in the accumulation kinetics are likely.While the separate analyses of the single variables did not lead to any significant contribution in the understanding of the phenomenainvolved in the product transformation, principal component analysis showed a common trend on ageing for all the studied sets.


2005 - Acido succinico quale causa della mancata rifermentazione spontanea in bottiglia del Lambrusco [Articolo su rivista]
S., Landi; Gullo, Maria; DE VERO, Luciana; Ulrici, Alessandro; R., Sidari; Giudici, Paolo
abstract

La rifermentazione in bottiglia dei Lambruschiè una pratica consolidata, che conferisce alvino caratteristiche sensoriali apprezzate daiconsumatori. Recentemente, e con sempremaggiore frequenza, è stata osservata la mancatarifermentazione del prodotto in bottiglia. Studipreliminari hanno messo in evidenza che lafrequenza della mancata rifermentazione èmaggiore nei vini imbottigliati precocementee senza aggiunta di lieviti. Inoltre, tutti icampioni esaminati che manifestano mancatarifermentazione contestualmente presentano valoridi acido succinico pari a 3 g/L. Va sempre tenutoconto che la crescita microbica è condizionatanon da un singolo fattore, ma da più fattori,perciò abbiamo allestito delle sperimentazioni chetenessero conto dei parametri più significativi,quali pH, densità di inoculo, concentrazione diacido succinico e concentrazione di etanolo. Unaprova di rifermentazione in bottiglia in condizionidi cantina ha definitivamente confermato la forteazione inibitrice dell’acido succinico sullo sviluppocellulare di Saccharomyces cerevisiae. I risultatisono coerenti con l’ipotesi che l’acido succinico,nell’ambito dei valori di pH e di concentrazionidi inoculo studiati, sia la causa della mancatarifermentazione.The spontaneous secondary alcoholicfermentation of the Lambrusco wine in bottle isa well-established practice that confer it someappreciated sensorial characteristics. Recently, andwith more frequency, it was observed the lack ofspontaneous secondary alcoholic fermentation inbottle. Preliminary studies have put in evidencethat the frequency of this problem is greater inearly bottled wines, produced without the additionof selected yeasts. Moreover, all the samples withthis problem have, at the same time, a succinicacid concentration of 3 g/L. These observationshave allowed the AA. to formulate the hypothesisthat succinic acid, in the presence of other limitingconditions, could be the cause of the lackedspontaneous secondary alcoholic. Since microbialgrowth is influenced by many factors, the AA. haveperformed several experiments considering themost significant parameters: pH, inoculum density,succinic acid content, and ethanol concentration.A secondary alcoholic fermentation test, carriedout under winery conditions, has confirmed thestrong inhibiting action of the succinic acid onSaccharomyces cerevisiae growth. The resultsare consistent with the hypothesis that, for thetested range, succinic acid is the reason of lackedspontaneous secondary alcoholic fermentation ofthe Lambrusco wine in bottle


2005 - Analisi multivariata di dati storici chimico-fisici e microbiologici delle acque potabili reggiane [Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Manzini, Daniela; Masino, Francesca; N., Fontani; Franchini, Giancarlo; G., Carapezzi
abstract

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2005 - Analisi multivariata di immagini digitali per la valutazione di matrici alimentari eterogenee [Articolo su rivista]
Ulrici, Alessandro; Manzini, Daniela; Masino, Francesca; Franchini, Giancarlo; Antonelli, Andrea; Foca, Giorgia
abstract

Questo lavoro descrive un nuovo metodo automatizzato per la classificazione di matricialimentari eterogenee sulla base delle comunifotografie digitali a colori. La caratteristica piùinnovativa di questo approccio consiste nellacapacità di identificare autonomamente gliaspetti che risultano essere maggiormente utiliper la classificazione degli alimenti esaminati. Ciòsignifica individuare le variabili più significativeper la classificazione dei campioni analizzatiin maniera cieca, ovvero senza la necessità dieffettuare alcuna assunzione a priori sulla naturadella matrice alimentare considerata. L’approccioprevede di rappresentare il contenuto in colore diogni immagine digitale sotto forma di un segnale,che noi abbiamo chiamato colorigramma, il qualeconsiste essenzialmente nella sequenza delle curvedi distribuzione dei tre valori di colore Rosso, Verdee Blu, nonché di vari parametri da essi derivati. Icolorigrammi così ottenuti possono quindi essereanalizzati mediante un algoritmo di classificazionee selezione di variabili chiamato WPTER. In questolavoro si presenta l’applicazione di tale approcciosu una serie di campioni di pesto alla genovese.Questo tipo di condimento, soprattutto a causa delladegradazione della clorofilla, tende a presentare unagrande variabilità di colore, che risulta però difficileda quantificare con metodi tradizionali di analisi acausa dell’aspetto eterogeneo.


2005 - Application of Gas-Cromatography for the characterization of Traditional Balsamic Vinegar [Abstract in Atti di Convegno]
Manzini, Daniela; Ulrici, Alessandro; Franchini, Giancarlo; Masino, Francesca; Antonelli, Andrea; Cocchi, Marina
abstract

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2005 - Classification of bread wheat flours in different quality categories by a wavelet-based feature selection/classification algorithm on NIR spectra [Articolo su rivista]
Cocchi, Marina; M., Corbellini; Foca, Giorgia; M., Lucisano; Ma, Pagani; Tassi, Lorenzo; Ulrici, Alessandro
abstract

In the Italian context, bread wheat flour is commercially classified in different quality categories on the basis of a Synthetic Index of Quality (Indice Sintetico di Qualit, ISQ), which is defined by means of specific parameters, i.e., hectolitric weight, falling number, protein content, alveographic indexes (W, P/L) and farinograph stability. The analyses involved in the determination of these parameters are expensive, time consuming and require specialized personnel, thus there is concern to develop alternative methods to be applied during the commercial transactions, when the products need to be characterized in very short times. For this reason, a fast technique such as an automated classification on the basis of NIR spectra acquired on the wheat flour samples could be a very useful tool. In this work, various wheat flour samples belonging to four different ISQ classes have been analysed by means of NIR spectroscopy, and the obtained spectra have been classified both by SIMCA applied to the signals subjected to different pretreatment methods, and by using a wavelet-based feature selection/classification algorithm, called WPTER. Due to the high overlap of the two intermediate quality classes, it was not possible to classify all the data set signals. However, when considering only the two extreme categories, an acceptable degree of class separation can be gained after feature selection by WPTER. Moreover, this approach allowed us to locate the NIR spectral regions that are mainly involved in the assignment of the wheat flour samples to these two quality categories.


2005 - Determinazione dei parametri chimico-fisici nell’Aceto Balsamico Tradizionale di Reggio Emilia (ABTRE) e loro correlazione con il giudizio sensoriale. [Relazione in Atti di Convegno]
Masino, Francesca; Ulrici, Alessandro; Antonelli, Andrea
abstract

Scopo di questo lavoro è stato quello valutare l’esistenza d’eventuali relazioni tra il giudizio sensoriale e alcuni parametri chimico-fisici misurati in ABTRE. L’analisi statistica univariata e multivariata dei dati ha evidenziato che i prodotti che ottengono il maggior punteggio sensoriale sono quelli caratterizzati da un adeguato contenuto acido e da una maggiore densità e dolcezza.


2005 - Dorsal premotor areas of nonhuman primate: functional flexibility in time domain [Articolo su rivista]
Lucchetti, Cristina; Ulrici, Alessandro; Bon, Leopoldo
abstract

A voluntary motor act requires recognition of the informational content of an instruction. An instruction may contain spatial and temporal information. The recently proved role of the monkey frontal cortex in time computation, as well as in motor preparation and motor learning, suggested that we investigate the relationship between premotor neuron discharges and the temporal feature of the visual instructions. To this purpose, we manipulated the duration of an instructional cue in a visuomotor task while recording unit activity. We found two types of premotor neurons characterised by a discharge varying in relation to the duration of the cue: (1) "motor-linked" neurons, with a specific premotor activity constantly bounded to the motor act; (2) "short-term encoders" neurons, with a premotor activity depending on the cue duration. The cue duration was the critical factor in determining the behaviour of the short-term encoders cells: when the cue ranged from 0.5 s to I s, they presented a preparatory activity: when the cue was longer, up to 2 s, they lost cells anticipated their discharge. The activity changed in few trials. These data confirm and highlight the role of frontal cortex in encoding specific cues with a temporal flexibility, which may be the expression of temporal learning and represent an extended aspect of cortical plasticity in time domain.


2005 - HPLC applications in Aceto Balsamico tradizionale quality assessment [Abstract in Atti di Convegno]
Masino, Francesca; Manzini, Daniela; Ulrici, Alessandro; Antonelli, Andrea
abstract

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2005 - Il Pianeta Acqua nel Continente Agricoltura (Congresso Nazionale dell’Associazione Italiana delle Società Scientifiche Agrarie – AISSA) [Altro]
Stanca, Am; Arru, Laura; Bignami, Cristina; Conte, Angela; Endrighi, Emiro; Franchini, ; Lofiego, D; Manicardi, Gian Carlo; Orlandini, Stefano; Pellegrini, ; Ulrici, Alessandro; Bacarella, Borin; Dazzi, Espen; Gallerani, Giupponi; Magnani, ; Pecchioni, Nicola; Poni, Rossi; Zanni,
abstract

Nell’era della specializzazione nel settore della Ricerca Scientifica, il Convegno ha l’ambizione di mettere insieme i singoli componenti del mondo scientifico agrario, di farli interagire tra di loro e di tentare di affrontare il problema Acqua in modo interdisciplinare. L’avanzamento delle conoscenze sul ruolo dell’acqua nel “Continente Agricoltura” garantirà ricadute di notevole interesse a breve, medio e lungo termine, per migliorare ulteriormente l’interazione “Organismi viventi di interesse agrario e forestale - Terreno – Atmosfera”. L’obiettivo finale è infatti quello di assicurare per il futuro uno sviluppo sostenibile, grazie alla razionale gestione di un fattore ambientale ed economico primario, l’Acqua.


2005 - Studio sensoriale sulle acque: approccio sperimentale [Relazione in Atti di Convegno]
Masino, Francesca; Antonelli, Andrea; Ulrici, Alessandro; Foca, Giorgia; Franchini, Giancarlo
abstract

Le caratteristiche sensoriali assumono un ruolo di fondamentale importanza nella determinazione della qualità alimentare. Per questi motivi, l’analisi sensoriale è uno strumento valido che, abbinata ad altre metodiche, consente d’individuare, sviluppare e migliorare le caratteristiche di un prodotto, oltre che a studiare le preferenze dei consumatori.L’acqua è, per definizione, priva di gusto ed odore e, proprio per questo motivo, le sue caratteristiche sensoriali sono difficili da valutare. In questo lavoro si descrive l’addestramento di un gruppo di persone (panel) per la valutazione sensoriale dell’acqua, ed alcune applicazioni a campioni reali


2005 - Use of multivariate analysis of MIR spectra to study bread staling [Articolo su rivista]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Different kinds of bread, stored at constant temperature and at controlled humidity conditions for a week since their manufacturing date, were analysed by Attenuated Total Reflectance-Fourier Transform InfraRed (ATR-FTIR) spectroscopy. The collected spectra were processed by Principal Component Analysis (PCA), in order to evaluate the changes occurring during bread ageing. For the sake of comparison, the 1060-950 cm(-1) spectral window has been also investigated by curve-fitting methods. It was observed that the first PC increases monotonically with ageing of samples. Furthermore, the more influential variables on PCl correspond to spectral regions where are located stretching and bending bands, which are mainly attributed to typical starch bonds vibrations.


2004 - A chemometric approach to the comparison of different sample treatments for metals determination by atomic absorption spectroscopy in aceto balsamico tradizionale di modena [Articolo su rivista]
Cocchi, Marina; Franchini, Giancarlo; D., Manzini; Marchetti, Andrea; M., Manfredini; Ulrici, Alessandro
abstract

A comparison of different digestion procedures has been carried out for the analysis of metal concentration in samples of vinegars and Aceto Balsamico Tradizionale of Modena (ABTM) coming from an unique barrel set. In particular, classical wet, dry ashing, and closed vessel microwave digestion procedure have been utilized and compared for each investigated species. In a few cases, direct metal determination on ABTM (without treatment procedure) is proposed as possible alternative to sample manipulation. Flame atomic absorption spectrometry was used for the quantification of iron and zinc, while graphite furnace atomic absorption spectrometry was used for all the other elements (i.e., chromium, manganese, cobalt, nickel, copper, cadmium, and lead). The comparison among the different sample treatments was carried out by the use of statistical and chemometric tools. In particular, principal component analysis and ANOVA approaches were used to discriminate between the diverse analytical methods. Furthermore, for all the dissolving techniques, the analytical metal recovery was always evaluated by the application of the recovery function on the same sample matrix. In general, the recoveries were fairly good, ranging from 90 to 103%, except for Cd and Pb with dry ashing, which showed recovery values close to 55% and 67%, respectively. As regards the metals concentration of the investigated samples, the experimental data reveal for some species the presence of concentration slightly over the legal limit fixed for wine and wine vinegar.


2004 - A study of the dielectric behavior and the liquid structure of a ternary solvent system [Articolo su rivista]
Cocchi, Marina; Franchini, Giancarlo; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; Zanardi, Chiara; Zannini, Paolo
abstract

The static dielectric constant of the {DMF(1) + ME(2) + DME(3)} ternary mixtures was measured as a function of temperature (25 less than or equal to t/degreesC less than or equal to 80) and composition, over the whole mole fraction range 0 less than or equal to x(1),x(2),x(3) less than or equal to 1. The experimental values were processed by an empirical equation accounting for the dependence epsilon = epsilon(T, phi(i)), where phi(i) is the volume fraction of the components. A comparison between calculated and experimental data shows that this fitting relationship can be effectively employed to predict epsilon values in correspondence to experimental data gaps. Starting from the experimental measurements, some derived quantities such as molar polarisation (P), and excess counterpart (P-E) were obtained. Both the excess properties, epsilon(E) and P-E, take values partly positive and partly negative under all experimental conditions. The values of the excess quantities are indicative of the presence of specific interactions among different components in the mixtures.


2004 - Analysis of the temperature and composition dependence of viscosimetric properties of 2-butanone+2-butanol solvent mixtures [Articolo su rivista]
S., Faranda; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Zucchi, Claudia
abstract

Kinematic viscosities were measured for 2-butanone + 2-butanol binary liquid mixtures with a capillary Ubbelohde routine viscometer in the temperature range from 273.15 to 353.15 K at atmospheric pressure, and covering the whole miscibility field (0 less than or equal to x(i) less than or equal to 1). Experimental data have been correlated by means of different empirical or semiempirical relationships, such as nu = nu(T), nu = nu(x(i)), and nu = nu(T, x(i)). Viscosity deviations, Deltanu, from ideal behavior are negative at all experimental conditions, confirming that structure breaking effects prevail in the liquids. Furthermore, the thermodynamics of viscous flow and excess Gibbs energy of activation of viscous flow, G*(E), have been calculated. As an alternative and complementary approach to such investigations, the fluidity (phi) of this binary system has been analyzed by the modified-Batschinski theory. The results are discussed in terms of the specific molecular interactions between the mixture components.


2004 - Application of NIR spectroscopy multivariate calibration to the quantification of durum wheat semolina adulteration with bread wheat flour [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2004 - Application of a wavelet-based algorithm on HS-SPME/GC signals for the classification of balsamic vinegars [Articolo su rivista]
Cocchi, Marina; Durante, Caterina; Foca, Giorgia; Manzini, Daniela; Marchetti, Andrea; Ulrici, Alessandro
abstract

A novel feature selection and classification algorithm (WPTER) based on the wavelet packet transform has been applied to the discrimination of balsamic vinegars, namely the typical made Aceto Balsamico Tradizionale di Modena, which gained the PDO denomination on the year 2000, from the industrial made Aceto Balsamico of the Modena district. All the samples have been characterized on the basis of the gas chromatographic (GC) profiles of the headspace (HS) volatile fraction, sampled by solid phase microextraction (SPME). Good discrimination between the two categories has been obtained both for the calibration and for the test set samples. GC-MS analysis allowed the identification of the peaks lying in the chromatographic regions selected by the algorithm, giving useful suggestions about the compounds which may be worth of further investigation in order to rationalize the chemical transformation occurring during the traditional making procedure. The proposed methodology seems very promising in authentication tasks, coupling some of the advantages of blind analysis with the possibility of acquiring chemical information, and giving, at the same time, very parsimonious multivariate classification models, which can be particularly suitable for data storage and handling.


2004 - Applicazione della calibrazione multivariata su spettri NIR per la quantificazione dell’adulterazione di semola di grano duro con farina di grano tenero [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2004 - Applicazione dell’algoritmo WPTER su spettri NIR di farine di frumento tenero per la classificazione nelle diverse classi di qualità [Relazione in Atti di Convegno]
Cocchi, Marina; Corbellini, M; Foca, Giorgia; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2004 - Automated evaluation of food colour by means of multivariate image analysis coupled to a wavelet-based classification algorithm [Articolo su rivista]
Antonelli, Andrea; Cocchi, Marina; Fava, Patrizia; Foca, Giorgia; Franchini, Giancarlo; Manzini, Daniela; Ulrici, Alessandro
abstract

This paper describes an approach for the colour-based classification of RGB images, taken with a common digital CCD camera oninhomogeneous food matrices. The aimwas that of elaborating a feature selection/classification method independent of the specific food matrixthat is analysed, in the sense that the variables that are the most relevant ones for the classification of the analysed samples are selected in a blindway, with no a priori assumptions on the basis of the nature of the considered food matrix.Aone-dimensional signal describing the colour contentof each acquired digital image, which we have called colourgram, is created as the contiguous sequence of the frequency distribution curves ofthe three red, green and blue colours values, of related parameters (also including hue, saturation and intensity) and of the scores values derivingfrom the PCA analysis of the unfolded 3D image array, together with the corresponding loadings values and eigenvalues. Once a sufficientnumber of digital images has been acquired, the corresponding colourgrams are then analysed by means of a feature selection/classificationalgorithm based on the wavelet transform, wavelet packet transform for efficient pattern recognition (WPTER). This approach was tested ona series of samples of “pesto”, a typical Italian vegetable pasta sauce, which presents high colour variability, mainly due to technologicalvariables (raw materials, processes) and to the degradation of chlorophylls during storage. Good classification results (100% of correctlyclassified objects with very parsimonious models) have been obtained, also in comparison with the visual evaluation results of a panel test.


2004 - Caratterizzazione chimico-fisica di amidi di varia origine [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Franchini, Giancarlo; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2004 - Classification of bread wheats in different baking categories by application of a wavelet-based feature selection/classification algorithm on NIR spectra [Relazione in Atti di Convegno]
Cocchi, Marina; Corbellini, M; Foca, Giorgia; PAGANI M., A; Lucisano, M; Ulrici, Alessandro
abstract

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2004 - Classification of cereal flours by chemometric analysis of MIR spectra [Articolo su rivista]
COCCHI, Marina; FOCA, Giorgia; M., LUCISANO; MARCHETTI, Andrea; MA, PAGANI; TASSI, Lorenzo; ULRICI, Alessandro
abstract

Different kinds of cereal flours submitted to various technological treatments were classified on the basis of their mid-infrared spectra by pattern recognition techniques. Classification in the wavelet domain was achieved by using the wavelet packet transform for efficient pattern recognition (WPTER) algorithm, which allowed singling out the most discriminant spectral regions. Principal component analysis (PCA) on the selected features showed an effective clustering of the analyzed flours. Satisfactory classification models were obtained both on training and test samples. Furthermore, mixtures of varying composition of the studied flours were distributed in the PCA space according to their composition.


2004 - Classificazione di frumenti teneri in diverse classi di qualità mediante applicazione sugli spettri NIR di un algoritmo di classificazione/selezione di variabili basato sulla trasformata wavelet [Relazione in Atti di Convegno]
Cocchi, Marina; Corbellini, M; Foca, Giorgia; PAGANI M., A; Lucisano, M; Ulrici, Alessandro
abstract

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2004 - Dielectric properties in ternary mixtures of ethane-1,2-diol+1,2-dimethoxyethane + water [Articolo su rivista]
Foca, Giorgia; Manfredini, Matteo; Manzini, Daniela; Marchetti, Andrea; Pigani, Laura; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract

The static dielectric constant (epsilon) of ethane-1,2-diol + 1,2-dimethoxyethane + water ternary mixtures was measured as a function of temperature (263.15 less than or equal to T (K) less than or equal to 353.15) and composition, over the complete mole fraction range 0 less than or equal to x(1), x(2), x(3) less than or equal to 1. The experimental values were analyzed by empirical relationships that accounted for the dependence epsilon = epsilon(T) and Y = Y(x(i)). A comparison between calculated and experimental data shows that these fitting relationships can be reliably used to predict epsilon values, along with other related properties, in areas of experimental data gaps. Starting from the experimental measurements, some derived quantities such as molar orientational polarization (P), dipolar interaction free energy (Fmu) and the relevant thermodynamic excess mixing properties (F-mu(E), (F) over bar (E)(mu,i)), were obtained. The values of the excess quantities are indicative of the presence of specific interactions between different components in the mixtures. A discussion of data in terms of the Kirkwood theory also provides information on the short-range intermolecular interactions, suggesting the formation of stable two-component adducts rather than of more complex moieties involving all three molecular species.


2004 - La Chimica degli Alimenti [Traduzione di Libro]
Antonelli, A.; Ulrici, A.
abstract

La chimica degli alimenti analizza le sostanze che si trovano nel cibo in grandi quantità (carboidrati, grassi, proteine, minerali e acqua) e quelle presenti in quantità minori (pigmenti, aromi, vitamine e conservanti). Quest’opera ha il pregio di dare chiare e precise definizioni dei composti chimici, anche di quelli non facilmente classificabili, senza banalizzazioni e mantenendo rigore scientifico e terminologico. Dei singoli composti chimici, vengono riportati gli aspetti funzionali più importanti, quali il comportamento durante i processi tecnologici e le proprietà sensoriali. I primi cinque capitoli si occupano dei "macrocostituenti" degli alimenti e sono quelli più decisamente chimici nell’impostazione. Nei successivi sei capitoli le sostanze sono riunite secondo il contributo che esse danno agli alimenti, piuttosto che in funzione della mera classificazione chimica. L’ultimo capitolo è dedicato all’acqua.


2004 - Spettroscopia NIR, un metodo di analisi veloce e promettente [Articolo su rivista]
M., Lucisano; Cocchi, Marina; M., Corbellini; Ma, Pagani; Ulrici, Alessandro; Foca, Giorgia
abstract

La spettroscopia NIR accoppiata all'analisi chemiometrica dei tracciati spettrali è illustarta com emetodica rapida, efficace e non distruttiva nel controllo di routine di alimenti cerealicoli


2004 - Studio delle relazioni tra acidità, concentrazione zuccherina, concentrazione di composti di natura furanica ed invecchiamento in batterie per la produzione di Aceto Balsamico Tradizionale di Reggio Emilia mediante metodologie chemiometriche [Relazione in Atti di Convegno]
Masino, Francesca; Chinnici, Fabio; Franchini, Giancarlo; Ulrici, Alessandro; Antonelli, Andrea
abstract

L’Aceto Balsamico Tradizionale (ABT) di Reggio Emilia deriva da mosto concentrato, che subisce un invecchiamento di almeno 12 anni in batterie costituite generalmente da 5 botti, diverse per capacità ed essenza legnosa. In questo lavoro di ricerca sono stati elaborati modelli matematici allo scopo di indagare le relazioni esistenti tra l’acidità, la concentrazione zuccherina, la concentrazione di composti di natura furanica e l’invecchiamento dell’ABT. I derivati furanici si originano durante la concentrazione del mosto, e il loro contenuto tende ad aumentare nel corso dell’invecchiamento, a causa della graduale perdita d’acqua che caratterizza il processo. Tuttavia le cinetiche d’accumulo sono diverse poiché i composti furanici, molecole piuttosto reattive, subiscono verosimilmente una rapida evoluzione in questa matrice. Ne risulta una cinetica di accumulo non sempre regolare, che richiede il ricorso a metodi d’indagine basati su tecniche chemiometriche multivariate, quale l’analisi delle componenti principali (PCA) per poter essere interpretata. Il derivato del furano più importante dal punto di vista quantitativo è l’idrossimetilfurfurale (HMF), dosato, mediante tecnica HPLC, insieme ad acido furoico (AF), furfurale (Fal) e 5-acetossimetilfurfurale (AMFA).


2003 - Applicazione dell’Algoritmo WPTER per la Classificazione di Spettri MIR di Farine Provenienti da Diversi Careali [Relazione in Atti di Convegno]
Cocchi, M.; Foca, G.; Marchetti, Andrea; Sighinolfi, S.; Tassi, L.; Ulrici, A.
abstract

l’Algoritmo WPTER è stato utilizzato per la Classificazione di prodotti da forno ottenuti impiegando cereali diversi mediante spettri MIR i


2003 - Applicazione dell’algoritmo WPTER per la classificazione di spettri MIR di farine provenienti da diversi cereali [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2003 - Density and volume properties of the 2-chloroethanol+2-methoxyethanol+1,2-dimethoxyethane ternary solvent system at different temperatures [Articolo su rivista]
Ferrari, Giorgia; Foca, Giorgia; M., Manfredini; Manzini, Daniela; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

The density of the 2-chloroethanol (CE) + 2-methoxyethanol (ME) + 1,2-dimethoxyethane (DME) ternary mixtures has been measured at different temperatures ranging from -10 to 80degreesC, and over the entire composition range. The experimental data have been used to check the validity of some relationships accounting for the dependence of the density on temperature and composition domains. Starting from the primary data, some derived quantities, such as excess molar volumes V-E, partial molar volumes (V) over bar (i) and partial excess molar volumes (V) over bar (E)(i), have been obtained. In these mixtures, V-E is always positive for the [CE(1) + ME(2)] binaries, while it is generally negative at all other experimental conditions, showing the greatest deviations along the binary axes corresponding to the binary subsystems in the sequence [CE(1) + DME(2)] < [CE(1) + ME(2)] < [ME(1) + DME(2)]. The results are compared and discussed to in terms of changes in molecular association and structural effects in these solvent systems.


2003 - Evaluation of the Colour of “Pesto” by means of Digital Image Analysis coupled to a Wavelet-Based Classification Algorithm [Relazione in Atti di Convegno]
Antonelli, Andrea; Fava, Patrizia; Foca, Giorgia; Franchini, Giancarlo; Ulrici, Alessandro
abstract

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2003 - Il sistema solvente ternario 1,2-etandiolo + 1,2-dimetossietano + acqua: proprietà dielettriche a diverse temperature [Relazione in Atti di Convegno]
Foca, Giorgia; Franchini, Giancarlo; Manfredini, Matteo; Manzini, Daniela; Tassi, Lorenzo; Ulrici, Alessandro; Zannini, Paolo
abstract

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2003 - Multicomponent Analysis of Electrochemical Signals in the Wavelet Domain [Articolo su rivista]
COCCHI, Marina; J. L., Hidalgo Hidalgo De Cisneros; I., Naranjo Rodruguez; J. M., Palacios Santnder; SEEBER, Renato; ULRICI, Alessandro
abstract

Successful applications of multivariate calibration in the field of electrochemistry have been recently reported, using various approaches such as multilinear regression (MLR), continuum regression, partial least squares regression (PLS) and artificial neural networks (ANN). Despite the good performance of these methods, it is nowadays accepted that they can benefit from data transformations aiming at removing baseline effects, reducing noise and compressing the data. In this context the wavelet transform seems a very promising tool. Here, we propose a methodology, based on the fast wavelet transform, for feature selection prior to calibration. As a benchmark, a data set consisting of lead and thallium mixtures measured by differential pulse anodic stripping voltammetry and giving seriously overlapped responses has been used. Three regression techniques are compared: MLR, PLS and ANN. Good predictive and effective models are obtained. Through inspection of the reconstructed signals, identification and interpretation of significant regions in the voltammograms are possible.


2003 - Multivariate calibration of analytical signals by WILMA (wavelet interface to linear modelling analysis) [Articolo su rivista]
Cocchi, Marina; Seeber, Renato; Ulrici, Alessandro
abstract

A novel algorithm based on coupling of the fast wavelet transform (FWT) with MLR and PLS regression techniques for the selection of optimal regression models between matrices of signals and response variables is presented: wavelet interface to linear modelling analysis (WILMA). The algorithm decomposes each signal into the FWT domain and then, by means of proper criteria, selects the wavelet coefficients that give the best regression models, as evaluated by the leave-one-out cross-validation criterion. The predictive ability of the regression model is then checked by means of external test sets. Moreover, the signals are reconstructed back in the original domain using only the selected wavelet coefficients, to allow for chemical interpretation of the results. The algorithm was tested on different literature data sets: two near-infrared data sets from Kalivas, on which the performances of many calibration algorithms have already been tested, and a data set consisting of lead and thallium mixtures measured by differential pulse anodic stripping voltammetry and giving seriously overlapped responses. Good results were obtained for all the studied data sets; in particular, for the data sets from Kalivas the WILMA models showed improved predictive capability. Copyright


2003 - Refractive properties of binary mixtures containing 1,2-dichloroethane + 2-methoxyethanol or 1,2-dimethoxyethane [Articolo su rivista]
M., Manfredini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Refractive index (n) and related properties such as molar refraction (R) have been investigated for DCE + ME and DCE + DME binary mixtures over the entire composition range, at different temperatures in the interval 0 less than or equal to t / degreesC less than or equal to 70. Some empirical and theoretical relationships have been applied to study the dependence of the measured and derived quantities on temperature and on binary composition. Furthermore, the excess functions n(E), R-E and the excess Kirkwood correlation parameters Deltag have been examined, in order to identify the presence of solvent-cosolvent adducts in these binary solvent systems. The results obtained have been interpreted on the basis of specific intermolecular interactions between different species. (C) 2003 Elsevier Science B.V. All rights reserved.


2003 - Valutazione del colore del “pesto” mediante analisi di immagini digitali e successiva classificazione utilizzando l’algoritmo WPTER [Relazione in Atti di Convegno]
Antonelli, Andrea; Fava, Patrizia; Foca, Giorgia; Franchini, Giancarlo; Ulrici, Alessandro
abstract

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2003 - Viscosimetric properties and internal structure of N,N-dimethylformamede+1,2-dimethoxyethane binary mixtures [Articolo su rivista]
Cocchi, Marina; M., Manfredini; D., Manzini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; Zannini, Paolo
abstract

The kinematic viscosities (v) of liquid binary mixtures of N,N-dimethylformamide and 1,2-dimethoxyethane were measured at 19 temperatures in the range -10 less than or equal to t / degreesC less than or equal to 80, employing the pure species and 9 their solutions covering the whole miscibility range expressed by the condition 0 less than or equal to x(i) less than or equal to 1. The measured values have been used to test some empirical equations of the type v=v(T), v=v(x(i)), and v=v(T,x(i)), in order to obtain useful correlation models with predictive ability in correspondence of the experimental data gaps. Starting from the experimental data, the excess kinematic viscosities (v(E)) have been calculated. Sign and magnitude of these quantities have been discussed in terms of type and nature of specific intermolecular interactions. Some derived quantities such as thermodynamic parameters of the viscous flow (DeltaG*, DeltaH* and DeltaS*), have been calculated on the basis of Eyring's model. Furthermore, the fluidity of this binary solvent system was analysed and interpreted following Hildebrand and modified-Hildebrand correlation models. (C) 2003 Elsevier Science B.V. All rights reserved.


2002 - Beta-functionalised polythiophenes as microelectrode modifiers in low conductive media [Articolo su rivista]
Cocchi, Marina; Franchini, Giancarlo; M., Manfredini; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; Zanardi, Chiara; Zannini, Paolo
abstract

A study on polythiophene coated microelectrodes is reported, the goal being that of checking the capability of these electrochemical systems to work in low conductive media. The possibility of electrochemically p-doping the polymer in the presence of very low concentrations or even in the absence of supporting electrolyte in the solution is ascertained, opening the way to the use of similar systems in pure solvent media. This result is obtained in such conditions that the presence of residual charges - and corresponding counterions - trapped inside the film coating can be reasonably hypothesised.


2002 - Caratterizzazione di farine di frumento mediante analisi PCA di spettri infrarossi [Articolo su rivista]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

La qualità risulta essere un criterio fondamentale per la scelta dei prodotti alimentari da parte dei consumatori, pertanto le tecniche anaitiche che si occupano del controllo della composizione chimica degli alimenti e dell'individuazione di eventuali adulterazioni sono in continuo aumento.


2002 - Classificazione di spettri MIR acquisiti su matrici di origine cerealicola mediante l’utilizzo dell’algoritmo WPTER [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

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2002 - Densities and excess molar volumes of binary mixtures containing 1,2-dichloroethane + 2-methoxyethanol or 1,2-dimethoxyethane at different temperatures [Articolo su rivista]
M., Manfredini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali
abstract

Density of the 1,2-dichloroethane + 2-methoxyethanol or 1,2-dimethoxyethane binary mixtures have been measured at different temperatures over the complete composition range. Several experimental measurements have been used to check the validity of the relationships accounting for the dependence of the density on temperature and composition, useful to obtain interpolated values in correspondence of the experimental data gaps. Starting from the primary data, some derived quantities, such as partial molar volumes, excess and partial excess molar volumes, have been obtained. In these mixtures, V-E is always positive for DCE + ME binaries, while an S-shaped dependence on composition at each temperature is obtained in DCE + DME system, showing positive values in the DCE rich-region and negative values at the opposite extreme. The results are compared and discussed to shed some light to the changes in molecular association and structural effects in these binary solvent systems.


2002 - Determination of Carboxylic Acids in Vinegars and Aceto Balsamico Tradizionale di Modena by HPLC and GC Methods. [Articolo su rivista]
Cocchi, Marina; P., Lambertini; Manzini, Daniela; Marchetti, Andrea; Ulrici, Alessandro
abstract

The presence of carboxylic acids in grape products has been investigated for a long time by researchers, from both the qualitative and quantitative points of view. Evaluation of carboxylic acids requires the study and optimization of some operative variables which are strictly related to the matrix. In particular, the determination of organic acids in real matrixes such as Aceto Balsamico Tradizionale of Modena (ABTM; a traditional balsamic vinegar made from cooked grape must) is often difficult because of the presence of numerous interferences that need to be removed by separation techniques. To this aim, in the present work a solid-phase extraction (SPE) method with C18 and NH2 exchangers was used to clean the ABTM samples prior to analysis or further treatments. Both HPLC and GC techniques were used to determine organic acids. The efficiency of these two different analytical techniques in the study of ABTM acidic composition has been evaluated. Both methods separately were not able to supply all the data related to carboxylic acids. In particular, HPLC allows acetic and lactic acids quantification, but gluconic and succinic acids are better determined by GC. As far as tartaric, citric, and malic acids are concerned, both HPLC and GC methods give statistically equivalent results. The variation of the single acidic species composition along a series of casks furnished interesting information regarding the chemical transformations taking place during the aging process of this product.


2002 - Il sistema ternario metanolo + etanolo + 1-propanolo: proprietà volumiche e disegno sperimentale di miscele solventi [Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Franchini, Giancarlo; Manfredini, Matteo; Manzini, Daniela; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Vignali, M.
abstract

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2002 - Kinematic viscosities of binary liquid mixtures of 2-butanone with 1,2-propanediol [Articolo su rivista]
M., Manfredini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; C., Zucchi
abstract

Kinematic viscosities of the binary 2-butanone (1) + 1,2-propanediol (2) solvent system have been measured for mixtures covering the whole miscibility range expressed by 0 less than or equal to x(i) less than or equal to 1, at 19 temperatures in the range -10 less than or equal to t/degreesC less than or equal to 80. The measured values have been used to test empirical equations that express the kinematic viscosities as functions of the composition and temperature. Excess kinematic viscosities (nu(E)) have also been calculated. Sign and magnitude of these quantities are discussed in terms of type and nature of specific intermolecular interactions. Furthermore, derived quantities such as thermodynamic parameters of viscous flow (DeltaGdouble dagger, DeltaHdouble dagger and DeltaSdouble dagger), are analyzed on the basis of Eyring's model. All the investigated excess mixing properties indicate the probable existence of stable two-component adducts in this binary solvent system.


2002 - Temperature and composition dependence of the refractive indices of the 2-chloroethanol + 2-methoxyethanol binary mixtures [Articolo su rivista]
Cocchi, Marina; M., Manfredini; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; Zanardi, Chiara; Zannini, Paolo
abstract

AbstractMeasurements of the refractive index n for the binary mixtures 2-chloroethanol + 2-methoxyethanol in the 0 ≤ T/°C ≤ 70 temperature range have been carried out with the purpose of checking the capability of empirical models to express physical quantity as a function of temperature and volume fraction, both separately and together, i.e., in a two independent variables expression. Furthermore, the experimental data have been used to calculate excess properties such as the excess refractive index, the excess molar refraction, and the excess Kirkwood parameter Ag over the whole composition range. The quantities obtained have been discussed and interpreted in terms of the type and nature of the specific intermolecular interactions between the components.


2002 - Viscosity of (ethane-1,2-diol+1,2-dimethoxyethane + water) at temperatures from 263.15 K to 353.15 K [Articolo su rivista]
Cocchi, Marina; M., Manfredini; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; Zanardi, Chiara
abstract

AbstractThe kinematic viscosity ν for (ethane-1,2-diol + 1,2-dimethoxyethane + water) was measured at 14 different ternary compositions covering the whole miscibility field, and at 19 temperatures in the range 263.15 T / K 353.15. The experimental values were fitted using empirical equations of the type ν = ν (T) and ν = ν (xi), respectively, in order to provide reliable models to account for the behaviour of the system. The excess kinematic viscosity νEhas been determined and interpreted in terms of the type and nature of the interactions among the components of the mixture. Using the experimental ν data, the thermodynamic properties ( ΔG * , ΔH * ,ΔS * ) of the viscous flow have been obtained from the Eyring’s approach and standard thermodynamic equations. Furthermore, excess mixing functions, such asΔG * E , have been determined, and found to evidence the existence of quite strong specific interactions among the components, probably due to the formation of hydrogen bonds and dipolar networks. However, all the calculated excess mixing properties suggest the absence of stable three-component adducts.


2001 - Density and volume properties of the 2-methoxyethanol+1,2-dimethoxyethane + water ternary solvent system at various temperatures [Articolo su rivista]
Cocchi, Marina; Marchetti, Andrea; Pigani, Laura; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari; Zanardi, Chiara
abstract

Densities (rho) of the ternary mixtures 2-methoxyethanol + 1,2-dimethoxyethane + water have been measured at 19 temperatures in the range -263.15 less than or equal toT/K less than or equal to 353.15. The experimental data were processed by empirical relations accounting for the dependence of rho on temperature and ternary composition expressed as mole fraction of the components (0 less than or equal to x(i) less than or equal to 1). All checked equations seem to be suitable for correlation purposes, in order to obtain interpolated values in correspondence to experimental data gaps. Furthermore, the excess molar volume (V-E) has been investigated to make evident the possibility of forming stable solvent-cosolvent adducts. The excess property has been interpreted on the basis of specific intermolecular interactions between the components.


2001 - The 2-Methoxyethanol + 1,2-Dimethoxyethane + Water Ternary System: Static Relative Permittivity from -10 to 80 °C [Articolo su rivista]
Cocchi, Marina; DE BENEDETTI, Pier Giuseppe; Marchetti, Andrea; Menziani, Maria Cristina; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Static relative permittivities of the 2-methoxyethanol + 1,2-dimethoxyethane + water ternary solvent system were measured as a function of temperature (-10 less than or equal to t/degreesC less than or equal to 80) and of composition, over the whole molar fractions range 0 less than or equal to x(1), x(2), x(3) less than or equal to 1. The experimental values have been used to test some empirical relationships accounting for the dependence of epsilon on T. x(i), and on T, x(i) couples of values. A comparison between calculated and experimental data shows that these relationships can be profitably employed to predict E values in correspondence to experimental data gaps. The excess dielectric permittivity, epsilon (E), assumes, in the most cases, negative values for any compositions of the mixtures. while the values of the excess molar polarization, PE, are positive. The large values of the excess quantities are indicative of the strong specific interactions among similar, as well as different molecules in the mixtures. Discussion of the data in terms of Kirkwood correlation factor also gives information on the short-range intermolecular interactions among the components. suggesting the formation of two-components adducts rather than of than mure complex moieties involving all three molecular species.


2001 - The Ethane-1,2-diol + 2-Methoxyethanol + 1,2-Dimethoxyethane Ternary Solvent System: Density and Volume Proprties at Different Temperatures. [Articolo su rivista]
Cocchi, Marina; M., Manfredini; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali
abstract

The density of the ethane-1,2-diol+2-methoxyethanol + 1,2-dimethoxyethane ternary mixtures has been measured at different temperatures ranging from-10 to 80° C, and over the whole composition range. The experimental data have been used to check the validity of some relationships accounting for the dependence of the density on temperature and composition, useful to evaluate the behaviour of this property in the whole temperature and composition domains. Starting from the primary data, some derived quantities, such as excess molar volumes, partial molar volumes and partial excess molar volumes, have been obtained. In these mixtures VE is generally negative at all the experimental conditions, showing the greatest deviations along the binary axes corresponding to the binary subsystems. The results are compared and discussed to get light to the changes in molecular association and structural effects in this solvent system.


2001 - WPTER: Wavelet Packet Transform for Efficient Pattern Recognition of Signals Estimation [Articolo su rivista]
Cocchi, Marina; Seeber, Renato; Ulrici, Alessandro
abstract

In the present work, we propose a novel algorithm based on the Wavelet Packet Transform WPT for pattern recognition of signals, which operates both feature selection and classification at the same time: Wavelet Packet Transform for Efficient pattern Recognition of signals WPTER . The distinctive characteristics of WPTER with respect to the previously proposed algorithms for the WPT-based classification of signals consist mainly of two aspects: 1 a Classification Ability criterion is introduced into the procedure for selection of the best discriminant basis; 2 the signals are reconstructed in the original domain by using only the selected wavelet coefficients, which allow for chemical interpretation of the results. The algorithm was first tested on an artificial simulated set of signals, consisting of a number of subsequent peaks, par- tially overlapped to each other, with added noise and baseline drift, simulating a three-class system. Then, it was applied to a data set consisting of X-ray diffractograms on fired tiles subjected to different firing cycles, aiming at discriminating the different firing methods on the basis of the phase composition. In both cases, satisfactory classifications were achieved.


2000 - Density and volume properties of ethane-1,2-diol+1,2-dimethoxyethane plus water ternary mixtures from-10 degrees to 80 degrees C [Articolo su rivista]
Baraldi, Pietro; Franchini, Giancarlo; Marchetti, Andrea; G., Sanna; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari
abstract

Thermodynamic interactions in the ethane-1,2-diol (1) + 1,2-dimethoxyethane (2) + water (3) ternary system have been investigated in terms of the excess molar volume, derived from density measurements at 19 different temperatures from -10 degrees to 80 degrees C. Fourteen three-component mixtures have been considered, covering the entire composition range. The excess molar volumes are discussed in terms of conformational changes induced in each component by the presence of another one. The results obtained support the hypothesis of the absence of any three-component complex adducts under all experimental conditions investigated.


2000 - Density and volumetric properties of ethane-1,2-diol plus di-ethylen-glycol mixtures at different temperatures [Articolo su rivista]
Cocchi, Marina; Marchetti, Andrea; Pigani, Laura; G., Sanna; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari; Zanardi, Chiara
abstract

The density of the ethane-1,2-diol (ED) + di-ethylen-glycol (DEG) binary mixtures has been measured at different temperatures over the complete composition range. The experimental measurements have been used to check the validity of relationships accounting for the dependence of the density on temperature and composition, useful to obtain interpolated values in the correspondence of the experimented data gaps. Starting from the primary data, some derived quantities, such as partial molar volumes, excess and partial excess molar volumes, have been obtained. In these mixtures, V-E presents an S-shaped dependence on composition at each temperature, showing negative values in the ED rich-region and positive values at the opposite extreme. The results are compared and discussed to get light to the: changes in molecular association and structural effects in this solvent system. (C) 2000 Elsevier Science B.V. All rights reserved.


2000 - Variation of volumic properties with temperature and composition of 2-butanone+1,2 propanediol binary mixtures [Articolo su rivista]
Marchetti, Andrea; Palyi, Gyula; Tassi, Lorenzo; Ulrici, Alessandro; Zucchi, Claudia
abstract

In this work we present experimental values of the density (rho), and some related quantities such as excess molar volumes (V-E), of the 2-butanone + 1,2-propanediol binary mixtures at various temperatures in the -10 less than or equal to t / degreesC less than or equal to 80 range and as a function of mole fraction. The experimental results have been fitted to some relationships of the type rho = rho (T), rho = rho (x(i)), and rho = rho (T,x(i)) to estimate the property in correspondence of the experimental data gaps. The observed behaviour has been interpreted on the basis of specific interactions and molecular features of the components. (C) 2000 Elsevier Science B.V. All rights reserved.


1999 - Density and excess molar volume values of binary mixtures of 2-chloroethanol + 1,2-ethanediol [Articolo su rivista]
FRANCHINI G., C; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Vaccari, G.
abstract

Density of the 2-chloroethanol (CE) + 1,2-ethanediol (ED) binary solvent system are presented at 19 temperatures in the -10 < t/°C < 80 range. The measured values have been used to test some empirical equations of the type ro=ro(t), ro=ro(Xi) and ro=ro(t,Xi), in order to provide useful interpolation procedures to obtain calculated values corresponding to the experimental data gaps. From the primary data, the excess molar volumes (V^E) have been calculated. The sign and magnitude of this quantity have been discussed in term of the type and nature of binary interactions. Furthermore, the derived quantities have fitted the Redlich-Kister equation with very good accuracy. some


1999 - Development of Quantitative Structure-Property Relationships (QSPR) using calculated descriptors for the prediction of the physico-chemical properties (nD, r, bp, e and h) of a series of organic solvents. [Articolo su rivista]
Cocchi, Marina; De Benedetti, Pier Giuseppe; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro
abstract

Quantitative structure-property relationship (QSPR) models were derived for predicting boiling point (at 760 mmHg), density (at 25 °C), viscosity (at 25 °C), static dielectric constant (at 25 °C), and refractive index (at 20 °C) of a series of pure organic solvents of structural formula X-CH2CH2-Y. A very large number of calculated molecular descriptors were derived by quantum chemical methods, molecular topology, and molecular geometry by using the CODESSA software package. A comparative analysis of the multiple linear regression techniques (heuristic and best multilinear regression) implemented in CODESSA, with the multivariate PLS/GOLPE method, has been carried out. The performance of the different regression models has been evaluated by the standard deviation of prediction errors, calculated for the compounds of both the training set (internal validation) and the test set (external validation). Satisfactory QSPR models, from both predictive and interpretative point of views, have been obtained for all the studied properties.


1999 - Kinematic viscosities of ternary mixtures containing ethane-1,2-diol, 2-methoxyethanol and water from-10 degrees C to 80 degrees C [Articolo su rivista]
Cocchi, Marina; Marchetti, Andrea; G., Sanna; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari
abstract

Kinematic viscosities (v) of the ternary ethane-1,2-diol (1) + 2-methoxyethanol (2)+ water (3) solvent system have been measured for 36 ternary mixtures covering the whole miscibility range expressed by the condition 0 <X-1,X-2,X-3 < 1, at 19 temperatures in the range - 10 less than or equal to t (degrees C) less than or equal to 80. The measured values have been used to test some empirical equations of the type v = v(t) and v = v(X-i), in order to provide for useful interpolation procedures to obtain calculated values in correspondence to the experimental data gaps. From the experimental data, the excess kinematic viscosities (v(E)) have been calculated. Sign and magnitude of these quantities have been discussed in terms of type and nature of specific intermolecular interactions. Furthermore, derived quantities such as thermodynamic parameters of the viscous flow (Delta G*, Delta H* and Delta S*), have been analysed on the basis of the Eyring's model. All the investigated excess mixing properties indicate the probable absence of stable three-component adducts in this ternary solvent system. (C) 1999 Elsevier Science B.V. All rights reserved.


1999 - Refractive indices of binary mixtures of (1,2-dichloroethane + 2-chloroethanol) at various temperatures [Articolo su rivista]
Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Vaccari, Giulia; G., Sanna
abstract

Measurements of the refractive index n(D) of(1,2-dichloroethane + 2-chloroethanol) in the temperature range 273.15 K less than or equal to T less than or equal to 343.15 K have been carried out for the purpose of checking the suitability of some empirical models of the type n(D) = n(T), n = n(x(i)), and n = n(T, x(i)) for the correlation and interpolation of experimental data to cover existing gaps. Furthermore, the experimental data have been used to calculate excess properties such as Delta n(D), R-E, and the excess Kirkwood parameter ag over the entire composition range. The results obtained have been discussed and interpreted in terms of the type and nature of the specific intermolecular interactions between the components.


1999 - Transform Methods in the Synthesis and Elaboration of Signals [Articolo su rivista]
Seeber, Renato; Ulrici, Alessandro
abstract

Different transform methods, from Fourier Transform to Wavelet Transform, are discussed and exemplified


1997 - Density and volumetric behavior of 1,2-dimethoxyethane plus water binary mixtures from -10 to 80 degrees C [Articolo su rivista]
Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract

The densities (rho) and excess molar volumes (V-E) for 1,2-dimethoxyethane + water binary mixtures were determined, when possible, at 19 different temperatures ranging from -10 up to +80 degrees C. The experimental measurements were used to test some empirical relations giving the dependence of the density on the temperature and binary composition: rho = rho(t), rho = rho(X-1), and rho = rho(t,X-1). Furthermore, the results of V-E calculations are discussed in terms of the influence of interactions between the components, of the order and degree of packing in the mixtures, and of the free-volume differences.