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, β-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.