Resveratrol in Wine: Extraction From Skin During Fermentation and Post-fermentation Standing of Must From Gamay Grapes

Abstract

Resveratrol (<i>cis</i>- and <i>trans</i>-isomers) was analyzed in skin, seeds and must of grape berries of Gamay from starting must to skin separation and in wine after malolactic fermentation. Its concentration increases in must while decreasing in skin and remains quite constant in seeds during alcoholic fermentation. Extraction from the skin correlates well with the increase of ethanol concentration in must up to day 6. After malolactic fermentation, the amount of resveratrol is about twice that measured at the end of alcoholic fermentation indicating a pool of resveratrol probably in the form of glucosides and (or) as on oligomeric form from which free resveratrol could be liberated by enzymatic activity of malolactic bacteria.