Influence of enological practices on the antioxidant activity of wines

Wine is a rich source of dietary antioxidants due to its content of phenolic compounds. The purpose of this work is to evaluate the impact of certain enological practices on antioxidant activity of wines. Enological practices included maceration for red wines, pressing degree for white wines, clarification in both types of wines using either albumin or gelatin and membrane filtration. As there is not yet a standard method accepted for the evaluation of the antioxidant activity of wines, the following were adapted and applied, oxygen radical absorbance capacity (ORAC), 2,2-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH). As pressure increased, the antioxidant activity of white wines also increased. Maceration time had a positive effect on antioxidant potential of red wines, and behaviour differed, depending on the grape variety (Tempranillo, Syrah, Cabernet Sauvignon). Clarification treatments did not significantly affect the phenolic composition or the antioxidant activity of wines. The information yielded can be used to obtain wines with maximum antioxidant capacity.