Characterization of Muscat wines aroma evolution using comprehensive gas chromatography followed by a post-analytic approach to 2D contour plots comparison.

This study presents the application of a headspace solid-phase microextraction (HS-SPME) method on the analysis of Muscat-based wines volatiles by comprehensive two-dimensional gas chromatography (GC×GC) and Time-Of-Flight mass spectrometry (TOF-MS). The aroma patterns were established for different samples of Asti Spumante and Moscato d'Asti wines, stored in bottles for 6 months at different temperatures. Wines stored at 5 °C for 6 months did not show significant changes in flavor; otherwise, the samples stored at 15 and 25 °C, showed a significant decrease in linalool, ß-damascenone, ethyl hexanoate, and ethyl octanoate levels. In these last samples, α-terpineol, hotrienol, nerol oxide, furanic linalool oxides A/B and rose oxide concentrations significantly increased. A mathematical approach was developed and applied to raw data exported after the chromatographic course, in order (i) to normalise different 2D chromatograms, permitting their direct comparison and (ii) to automatically identify and calculate from pixel-to-pixel re-designed 2D chromatograms any differences among key volatile compounds.

Microbiological and chemical characterization of a typical Italian cheese: Robiola di Roccaverano.

Robiola di Roccaverano is a traditional Italian goat's milk cheese carrying a Protected Designation of Origin (PDO). The present work studied both cheese microflora and cheese physicochemical characteristics to obtain a more accurate description of this PDO product. Multivariate statistical analysis (PCA) was performed to evaluate the influence of cheesemaking (artisanal and industrial), ripening time, and season of production on cheese characteristics. Multiplex PCR and fatty acid methyl esters (FAMEs) were used to identify the kind of milk employed by Robiola di Roccaverano producers. The results obtained highlight some product differences between the artisanal and industrial products. These differences were most evident in the microbiological data. The use of PCA allowed cheese samples to cluster on the basis of their age (fresh or ripened), the origin of production (artisanal and industrial), and even the season of production. Gross composition, microbiological parameters, and gas chromatographic analyses of FAMEs provided the most important parameters for Robiola di Roccaverano cheese characterization.