EVOLUTION OF ANTHOCYANIN PROFILES FROM GRAPE TO WINE

Aims: This study aimed at acquiring knowledge on the evolution of anthocyanins from grape to wine and the possibility of deducing the varietal origin of a wine from its anthocyanin profile. Methods and results: The anthocyanin “fingerprints”, or profiles, of a series of autochthonous Sicilian accessions and in the respective young wines were determined by HPLC-DAD in 2008. Data were evaluated by taking into account the development of percentages of side-ring disubstituted and trisubstituted anthocyanins, the ratio between acetylated and p-coumaroylated derivatives, and PCA results. From grape until the end of alcoholic fermentation, percentages of 3-glucosides of cyanidin, peonidin, delphinidin and p-coumaroylglucosides decreased, whereas those of malvidin-3-glucoside, acetylated derivatives and, in some cases, petunidin-3-glucoside increased. In many but not all wines, after malolactic fermentation, the percentages of p-coumaroylated derivatives decreased further and those of cyanidin-3-glucoside and acetylated derivatives increased; fewer variations were observed in malvidin-3-glucoside values. Conclusions: From grapes to young wines, anthocyanin profiles varied mainly because of activity by PPO, yeasts and lactic bacteria. However, they were substantially retained in wines from varieties in which trisubstituted side-ring anthocyanins prevailed, but was dramatically different from the respective grapes in wines from varieties rich in disubstituted anthocyanins, or ones in which the disubstituted form prevailed over the trisubstituted one. PCA analysis confirmed these findings. Significance and impact of the study: Only in varieties in which the anthocyanin profiles of grapes are characterized by low percentages of disubstituted side-ring forms is it possible to gain information about the varietal origin of a young wine by comparing the profiles of both grape and wine. However, great care is required.