Aroma compounds as markers of the changes in sherry wines subjected to biological ageing

Capillary-column gas chromatography was used to determine 63 aroma compounds in 9 very pale sherry wines, fino type, subjected to biological ageing under industrial conditions for 1, 3 and 5 years. The contents in aroma compounds were related to the wine ageing time by means of a simple linear regression model. The compounds that exhibited a high correlation coefficient (r>0.90) and simultaneously a high odour impact value (OAV > 5) were additionally subjected to principal component analysis. The first component was found to account for 93.12% of the changes in such compounds during the biological ageing process. The greatest contributions to this component were those from sotolon and 1,1-diethoxyethane, both related to the acetaldehyde produced by the metabolism of flor yeasts, and Z-whisky lactone synthesized from its precursors extracted from the casks wood where the wines were aged. The use of these compounds as markers for biological ageing is advantageous because their changes in concentrations is taken into account as well as their odorant impact.