No abstract

Ricotta cheese is a dairy product characterised by a short shelf life. The aim of this study was to monitor changes occurring duringstorage of packed industrial ricotta cheese using a simple and fast method. Several samples of manufactured ricotta cheese were monitored during storage at three different temperatures (3, 10 and 20°C). Spectral data were collected over the range 12000 to 4400 cm -1 using a Fourier transform near infrared (FT-NIR) spectrometer fi tted with an optic fi bre working in diffuse refl ectance. Some chemical and rheological parameters were also measured. Principal component analysis (PCA) was applied as an exploratory chemometric technique to each one of the three sets of data (FT-NIR, chemical and rheological data) and a calibration model between the NIR data set and chemical and rheological indices was developed by means of partial least squares regression. The PCA results showed in all cases the infl uence of the storage temperature on the shelf life trend and were able to identify a critical day of shelf life for each storage temperature.

No abstract

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.

No abstract

The aim of this work was to investigate the feasibility of near infrared (NIR) spectroscopy both in quantifying the residual water content of osmo-air dehydrated apple rings and in differentiating them on the basis of the sugar solution used in the osmotic pretreatment so identifying the osmotic syrup used. In order to achieve this, a set of products obtained by different processing conditions was created. Apple rings were dipped for different lengths of time (30, 60 and 90 min) in three different sugar solutions at the same water activity (aw = 0.90): sucrose (59% wt / wt), maltose (62% wt / wt) and a mixture (53% wt / wt) of fructose, glucose and sucrose having the same composition as apple. Air drying was then performed at different temperatures (70°, 80°, 90°C) and the obtained osmo-air dehydrated apple rings were packed in polypropylene film under vacuum in order to avoid water absorption phenomena. NIR spectra, in the range 10,000-4000 cm-1 , were recorded directly on packed apple rings using a FT-NIR spectrometer equipped with fiber optic probe. In calibrating the residual water content the coefficient of determination (R 2) was 0.93, the RPD value was 3.33 and RER value was 13.79, which could be considered, for our purposes, suitable for controlling the dehydration process. Moreover, applying a classification statistic method on NIR data, such as PLS discrimination analysis, it was also possible to identify correctly which sugar solution was used in the osmotic pre-treatment independently of the conditions used. Two-dimensional correlation analysis was also carried out, in order to investigate how the ratios between the main constituents, sugars and water, involved in the osmo-air dehydration varied as a function of the process variable used.

Food packaging and coatings have the well-known and established functions of containment, protection and handling facilitation of the food packaged inside. Fast methods able to classify, sort and identify the quality and the stability characteristics associated with the various packaging and coating materials are required along the food chain in order to validate their properties. Innovative products deriving from organic polymers, recently submitted for Italian patent (no. 102015000018950), were used as coatings both in the food industry for two types of cheese (provola and caciotta) and in postharvest management to modulate fruit ripening of winter melons during storage at 13°C. This work aimed at studying the effect of the differences in performance and permeability properties of the coatings after their application and during the ripening and storage period by using near infrared spectroscopy and exploiting the aquaphotomics approach, where information on the absorption bands can provide a distinct knowledge of water vibrations and intrinsic interactions between water and other components of the aqueous system. Applying multivariate spectral analysis, it was found that changes of water matrix under perturbation reflect other molecules surrounded by water, allowing the identification of specific fingerprints associated with coating characteristics and with the ripening/storage trends. Each coating generated a specific fingerprint for the same product suggesting that aquagrams could be a useful and fast procedure able to distinguish the effects of different coating materials on the same matrices. It was also proved that starting from similar aquagrams it was possible to follow and monitor the storage trends.

No abstract