Cristina Alamprese

Identification and quantification of turkey meat adulteration in fresh, frozen-thawed and cooked minced beef by FT-NIR spectroscopy and chemometrics.

This work aims at the development of a method based on FT-NIR spectroscopy and multivariate analysis for the identification and quantification of minced beef meat adulteration with turkey meat. Samples were analyzed as raw, frozen-thawed and cooked. Different multivariate regression and class-modeling strategies were evaluated. PLS regression models with R(2) in prediction higher than 0.884 and RMSEP lower than 10.8% were developed. PLS-DA applied to discriminate each type of sample in two classes (adulteration threshold=20%) showed values of sensitivity and specificity in prediction higher than 0.84 and 0.76, respectively. Thus, the study demonstrates that FT-NIR spectroscopy coupled with suitable chemometric strategies is a reliable tool for the identification and quantification of minced beef adulteration with turkey meat not only in fresh products, but also in frozen-thawed and cooked samples. This achievement is of crucial importance in the meat industry due to the increasing number of processed meat products, in which technological treatments can mask a possible inter-species adulteration.

Ripening of salami: Assessment of colour and aspect evolution using image analysis and multivariate image analysis

During ripening of salami, colour changes occur due to oxidation phenomena involving myoglobin. Moreover, shrinkage due to dehydration results in aspect modifications, mainly ascribable to fat aggregation. The aim of this work was the application of image analysis (IA) and multivariate image analysis (MIA) techniques to the study of colour and aspect changes occurring in salami during ripening. IA results showed that red, green, blue, and intensity parameters decreased due to the development of a global darker colour, while Heterogeneity increased due to fat aggregation. By applying MIA, different salami slice areas corresponding to fat and three different degrees of oxidised meat were identified and quantified. It was thus possible to study the trend of these different areas as a function of ripening, making objective an evaluation usually performed by subjective visual inspection.

Monitoring of lactic acid fermentation process using Fourier transform near infrared spectroscopy

The aim of this paper was to evaluate the suitability of Fourier transform near infrared (FT-NIR) spectroscopy, combined with multivariate data analysis, to monitor milk lactic acid fermentation as an indication of possible deviations in quality parameters. Fermentation trials performed with different inocula (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus as single or in mixed cultures) at three incubation temperatures (37°C, 41°C and 45°C) were monitored by FT-NIR spectroscopy. Rheological and conventional quality parameters (microbial counts, pH, titratable acidity, lactose, galactose and lactic acid concentrations) were used as reference values to assess the findings with FT-NIR spectroscopy. Principal component analysis was applied to spectra to uncover molecular modifications. PC1 scores, rheological data and conventional quality parameter values were modelled as a function of fermentation time to designate critical points all along the process. Results showed that FT-NIR spectroscopy is a useful tool for real-time assessment of curd development during fermentation, offering crucial information in agreement with rheology and conventional quality parameters.

Effects of housing system and age of laying hens on egg performance in fresh pasta production: pasta cooking behaviour

BACKGROUND Very few studies concern the effects of layer housing systems and age on egg technological properties. Thus the aim of this work was to study the influence of these two factors on egg performance in fresh pasta production, focusing on pasta cooking behaviour. Samples of pasta subjected to analysis were prepared with eggs laid by Hy-Line Brown hens (from 27 to 68 weeks old) housed in cage, barn and organic systems. RESULTS Higher average values of weight increase and matter loss during pasta cooking were observed for samples prepared with eggs laid by older hens. Such cooking behaviour indicated the development of a weaker pasta protein network, resulting from a decrease in the quantity of albumen protein and an increase in fat content, which is due to the reduction in albumen/yolk ratio during hen aging. The housing system had a significant effect only on matter loss in cooking water, but differences between samples were so small as to be unlikely perceived by consumers. CONCLUSION Both hen age and housing system significantly affected pasta cooking behaviour, but the greatest effect was exerted by the hen age.

Handheld NIR device: A non-targeted approach to assess authenticity of fish fillets and patties

This study evaluates the reliability of a handheld NIR device in distinguishing fillets and patties of Atlantic cod (n = 80) from those of haddock (n = 90), in comparison with a FT-NIR benchtop spectrometer. The authentication issue was faced by Linear Discriminant Analysis (LDA) and Soft Independent Modelling of Class Analogy (SIMCA), pre-treating spectral data with different algorithms, and validating models both internally and externally. The best LDA models gave 100% correct classification in prediction. Sensitivity >65% and specificity >74% in prediction were calculated for the best SIMCA models. No significant differences (P > .05) were found between the two instruments by McNemar test. Thus, the work demonstrated that a handheld NIR device can be a simple, cost-effective, and reliable alternative to benchtop spectrometers in fish fillet and patty authentication. These important findings can help in improving commercial fraud fight, extending the possibility to authenticate fish species also in processed products.

Shelf life extension of whole-wheat breadsticks: Formulation and packaging strategies

The aim of this study was the shelf life extension of whole-wheat breadsticks through the addition of a rosemary extract and packaging under nitrogen. Shelf life was studied at four temperatures (20, 27, 35, 48°C) for up to 200 storage days. The minimal changes observed in moisture, water activity and texture of the samples, coupled with the high peroxide values (13-539meqO2/kgfat) measured at the end of storage, and the exponential increase of hexanal concentrations (up to 13-34mg/kg) confirmed that quality decay of whole-wheat breadsticks is mainly associated to lipid oxidation. The kinetic study of oxidation development and the consumer sensory acceptance determined by the survival analysis demonstrated that the rosemary extract addition yields a 42% shelf life extension, higher than that observed using nitrogen in the package (24-29%). The combination of the formulation and packaging strategies gave the best result (83% shelf life extension at 25°C).

Discriminative capacities of infrared spectroscopy and e-nose on Turkish olive oils

The potentials of Fourier transform (FT) near- (NIR) and mid-infrared (IR) spectroscopy, and electronic nose (e-nose) on varietal classification of Turkish olive oils were demonstrated. A total of 63 samples were analyzed, comprising Ayvalik, Memecik, and Erkence oils. Spectra were pretreated with standard normal variate and second derivative. Classification models were built with orthogonal partial least square-discriminant analysis (OPLS-DA), considering the single data sets and also the combined FT-NIR-IR spectra. OPLS-DA models were validated both by cross validation and external prediction. All the models gave good results, being the average correct classification percentages in prediction higher than 90% for spectroscopic data and equal to 82% for e-nose data. The combined FT-NIR-IR data set gave the best results in terms of coefficients of determination (0.95 and 0.67). Different e-nose sensors discriminated Ayvalik, Memecik, and Erkence oils, explaining their distinct aromatic profiles.

Effect of low-protein diets in heavy pigs on dry-cured ham quality characteristics

The present work aimed at evaluating if heavy pig low-protein diets balanced for amino acid (AA) profile affect the quality characteristics of dry cured hams. To the aim, 40 hams obtained by Italian Duroc×Italian Large White pigs fed three different dietary crude protein and indispensable AA levels were compared with those obtained by a conventional Parma ham Protected Designation of Origin diet (C). No physico-chemical (aw, pH), chemical (gross composition, NaCl, lipid peroxidation, non-protein nitrogen, total volatile bases) or sensory characteristics of hams were systematically affected by the administered diet, animal sex or their interaction with the exception of total and subcutaneous fat (the latter measured by an image analysis procedure). Considering gilts, low-protein diets resulted in samples with higher fat content and subcutaneous fat thickness with respect to hams obtained with C diet. In conclusion, low protein diets in the finishing phase of pig breeding could reduce the environmental impact due to nitrogen excretion without significantly affecting ham quality.

The Use of Egg and Egg Products in Pasta Production

Eggs are multifunctional ingredients, used in a number of food products due to their diverse technological properties. In pasta, they are added to improve nutrition, color, texture, and cooking behavior. After a brief introduction on egg pasta nomenclature and government regulation of its egg content, the production processes of fresh and dry egg pasta are illustrated with emphasis on the structuring role of eggs. Changing the natural albumen to yolk ratio is suggested as a useful tool for modulating egg pasta quality. The exploitation of egg structuring capacities for gluten-free pasta production is discussed as well as the potential use of nonchicken eggs in pasta formulation. Finally, analytical methods for egg content and quality determination in pasta are reviewed.

Effect of fresh pork meat conditioning on quality characteristics of salami

The aim of this work was to evaluate the effect of pork meat conditioning under different relative humidity (RH) values on salami quality characteristics. During a 6days conditioning period at 0°C under two levels of RH (95% vs. 80%), meat pH and weight loss were measured. Salami characteristics (moisture, weight loss, texture, appearance properties) were evaluated during 20days of ripening. Results showed that conditioning at 80% RH yielded a significantly drier meat, being the weight loss rate 1.6 times higher than at 95% RH. The lower water content of meat allowed a shorter salami ripening phase, guaranteeing an appropriate weight loss and the development of the desired texture, while maintaining good appearance properties. The acceleration of this production phase represents a clear economic advantage for producers and consumers, leading to higher profit margins and lower retail prices. The possibility of using FT-NIR spectroscopy as a valid tool for the rapid evaluation of salami ripening was also demonstrated.