Papers by Stefania Barzaghi
Journal of AOAC International, Sep 1, 2002
An interlaboratory study, with the participation of 8 laboratories, was conducted to evaluate a s... more An interlaboratory study, with the participation of 8 laboratories, was conducted to evaluate a sodium dodecyl sulfate-capillary gel electrophoresis method for determination of adulteration of milk powder with soy and pea proteins. Calibration standards (0-8%, w/w, soy and pea protein in total protein) and adulterated skim milk powders (0-5%, w/w, soy and pea proteins in total protein) were produced. Vegetal proteins were determined after removal of milk proteins by pretreatment of the samples with tetraborate-EDTA buffer, pH 8.3. Repeatability standard deviations ranged from 9 to 15% and reproducibility standard deviations ranged from 25 to 30% in the samples containing 5% vegetal protein in total protein.
European Food Research and Technology, May 11, 2023
Nir News, Feb 1, 2010
The applicability of near-infrared (NIR) spectroscopy to bioethanol production is investigated. T... more The applicability of near-infrared (NIR) spectroscopy to bioethanol production is investigated. The NIR technique can provide assistance for rapid process monitoring, because organic compounds absorb radiation in the wavelength range 1100-2300 nm. For quantification of a sample's chemical composition, a calibration model is required that relates the measured spectral NIR absorbances to concentrations. For calibration, the concentrations in g/l are determined by the analytical reference method high performance liquid chromatography (HPLC). The calibration models are built and validated for moisture, protein, and starch in the feedstock material, and for glucose, ethanol, glycerol, lactic acid, acetic acid, maltose, fructose, and arabinose in the processed broths. These broths are prepared in laboratory experiments: The ground cereal samples are fermented to alcoholic broths ('mash'), which are divided into an ethanol fraction and the residual fraction 'stillage' by distillation. The NIR technology together with chemometrics proved itself beneficial for fast monitoring of the current state of the bioethanol process, primarily for higher concentrated substances (>1 g/l).
Journal of Dairy Research
We evaluated the possibility of increasing the storage temperature of raw milk for Provolone Valp... more We evaluated the possibility of increasing the storage temperature of raw milk for Provolone Valpadana cheesemaking, to identify the most suitable conditions of time and temperature for a pre-maturation process. We used Principal Component Analysis (PCA) to analyze the overall effects of different storage conditions on chemical, nutritional and technological characteristics of the raw milk. Four different thermal storage cycles, two at fixed temperature/time (6 and 12°C for 60 h) and two with two-phase thermal cycle (10 and 12°C for 15 h, followed by refrigeration at 4°C for 45 h) were studied. Although a moderate heterogeneity among raw milks from the 11 producers of Provolone Valpadana cheese was observed, PCA revealed the critical aspects of the extreme storage conditions (60 h of refrigeration). Some samples resulted in anomalous behaviors, probably related to unexpected fermentation phenomena occurring with increasing storage temperature. The acidification and the increase in t...
Sense the Real Change: Proceedings of the 20th International Conference on Near Infrared Spectroscopy, 2022
Scienza e tecnica lattiero-casearia, Mar 1, 2022
The aim of this work was to study the effect of raw milk stored at 6° and 12°C for 60 h on Provol... more The aim of this work was to study the effect of raw milk stored at 6° and 12°C for 60 h on Provolone Valpadana PDO cheese characteristics. Microbiological, chemical, and hygienic aspects were considered, as well as the sensorial quality. Materials and Methods: Microbiological analyses to determine different bacterial groups, hygiene indicators and pathogens, and chemical composition analysis were carried out both on milk after storage and on cheeses during ripening. Proteolysis by capillary electrophoresis, free amino acids by ion exchange HPLC, volatile compounds by SPME/GC/MS were also evaluated. Sensory properties of the cheeses were estimated by triangular test. Results: None of the experimental cheeses showed hygienic problems, despite the high microbial load of milk used. Anyway, the use of milk stored at 12°C for 60 h turned to be critical for cheesemaking and cracks in ripened cheese were detected, not observed using milk stored at 6°C.
Our purpose was to produce, with only ewe's milk and the technology of Gorgonzola, a blue vei... more Our purpose was to produce, with only ewe's milk and the technology of Gorgonzola, a blue veined cheese new for Italy. From 200 kg ofpasteurized ewe's milk, added of lactic acid starter cultures and Penicillium vendemanii, three shapes have been obtained, and have been matured for 79 (ripened) and 120 days (old). In the cheese has been evidenced the presence of the added microorganisms, but also of autochthony thermoduric lactic acid bacteria that, beyond contributing to the maturation processes, constitutes a tie with the territory of production. The proteolysis has turned out intense in the ripened cheese, and still more in the old product, since the presence offractions of low molecular weight and free amino acids, mainly Leucin, Valin, Lysin and Glutammic Acid, has been reported. The influence of lipolytic enzymes of the moulds is evidenced by the free fatty acid presence, especially Caproic, Caprilic and Capric acid that confers a gently ewe's flavour The more volat...
Food Control, 2008
Vastedda is a Sicilian pasta filata sheep cheese made from raw milk without starter addition, tra... more Vastedda is a Sicilian pasta filata sheep cheese made from raw milk without starter addition, traditionally consumed fresh on the local market. To extend its consumption also out of Sicily, a prolonged shelf-life is needed. Production technology, chemical and microbiological aspects of fresh Vastedda cheese and within 60 days of storage were studied. Vastedda, according to Codex Alimentarius, resulted a semi-hard, medium fat cheese, but the large variability of composition makes the definition of a narrow standard of the product difficult. Lactic acid bacteria were the dominant microflora in spite of the heat stress given by the stretching of the curd. Listeria monocytogenes and Salmonella spp., were absent and coagulase positive staphylococci were always lower than 100 cfu/g. The variability among producers is amplified by the variability of the cheese during shelf-life. Sugars and organic acids content largely changed during the 60-day storage, mainly for the brine unsalted variety. To continue to identify this cheese as a fresh one, the storage of traditional Vastedda cheese should not be longer than 30 days.
Scienza e Tecnica Lattiero Casearia, 2021
Objective: The duration and refrigeration temperature of raw milk are among the main causes of th... more Objective: The duration and refrigeration temperature of raw milk are among the main causes of the alteration of the milk micro flora activity, which could even compromise its hygienic quality. The objective of this work was to evaluate the influence of an increase in the refrigeration temperature of raw milk for cheese making (Provolone Valpadana PDO) on some parameters of chemical and nutritional interest. Materials and Methods: raw milk samples from 7 farmers were analyzed for their contents in: some organic acids, calcium and phosphorus (total and soluble contents), vitamin A and a process index, (the Degree of Retinol Isomerization, DRI). Results: Lactic acid and DRI were the most influenced parameters by the storage temperature of the milk, probably due to a modification in the activity of the milk micro flora. However, the retinol isomerization did not lead to a significant decrease in the vitamin A content of the samples. Similarly, an increase in the soluble calcium content was observed with increasing the refrigeration temperature from 6 to 12 °C. Conclusions: The obtained results have shown that changes in the technological processes of the dairy sector should also take into account the evaluation of the effects on the chemical and nutritional characteristics of milk, and not only the milk microbiological aspects.
Proceedings of the 18th International Conference on Near Infrared Spectroscopy
The GRANIR project founded by the Grana Padano Protection Consortium and developed by CREA-ZA res... more The GRANIR project founded by the Grana Padano Protection Consortium and developed by CREA-ZA research centre is devoted to the development of a rapid and economic method for the chemical characterisation of Grana Padano PDO cheese based on near infrared (NIR) spectroscopy technology. For this purpose, the Consortium purchased several portable spectrometers XNIR TM (dinamica generale ® , Poggio Rusco, MN, Italy), to be assigned to the Consortium staff for screening operations of production batches in the fire-branding step, in warehouses and at the packaging step, on cheese paste. To develop predictive models and to evaluate the performance of the portable instruments, 195 samples of Grana Padano were scanned directly on the whole open wheel, scanning both rind and cheese paste. Robust models were built for the prediction of dry matter, fat, fat/dry matter, proteins and proteins/dry matter content using average spectra of rind and paste and chemical data of cheese paste. Additional spectra acquired with two other instruments were included in order to make the models less sensitive to different instruments. Spectra of the same samples acquired at different temperatures (10, 16 and 25 °C) were also added to the dataset in order to reduce the influence of temperature on prediction results. The obtained results showed a satisfactory predictive ability of the models built with portable NIR spectrometers, with respect to the chemical composition of Grana Padano cheese, showing root mean square errors in prediction comparable to that obtained with a Fourier-Transform NIR benchtop instrument. This allows the estimation of average cheese composition, at batch level, using multiple scans taken on a high number of wheels.
en sciences et technologies pour l'environnement et l'agriculture.
Molecules, 2021
Proteomics and metabolomics are analytic tools used in combination with bioinformatics to study p... more Proteomics and metabolomics are analytic tools used in combination with bioinformatics to study proteins and metabolites which contribute to describing complex biological systems. The growing interest in research concerning the resolution of these systems has stimulated the development of sophisticated procedures and new applications. This paper introduces the evolution of statistical techniques for the treatment of data, suggesting the possibility to successfully characterize the milk-whey syneresis process by applying two-dimensional correlation analysis (2DCOR) to a series of CE electropherograms referring to milk-whey samples collected during cheese manufacturing. Two cheese-making processes to produce hard cheese (Grana type) and fresh cheese (Crescenza) were taken as models. The applied chemometric tools were shown to be useful for the treatment of data acquired in a systematically perturbed chemical system as a function of time.
Journal of applied botany and food quality, 2016
The seed γ-conglutin protein fraction of white lupin has particular pharmacological interest, but... more The seed γ-conglutin protein fraction of white lupin has particular pharmacological interest, but its industrial production is hindered by low content in the seed. This study provides an unprecedented assessment of genotypic and environmental variation for seed content and production of γ-conglutin, exploring also the ability of Near-Infrared Spectroscopy (NIRS) to predict seed γ-conglutin content. Significant (P < 0.01) genetic variation for seed γ-conglutin content emerged among ten genotypes (cultivars or breeding lines) across three environments (range: 1.59-2.02 %) and five genotypes in other two environments (range: 1.47-1.80 %). Genotype variation was found also for seed protein content and γ-conglutin proportion on total protein, the latter trait having higher impact than the former on genotype variation for seed γ-conglutin content. The production of γ-conglutin per unit area was affected also by genotype yielding ability beside genotype seed γ-conglutin content. No geno...
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Papers by Stefania Barzaghi