Extended maceration of must improves phenolic composition and antioxidant potential of Touriga Nacional tropical wine

The Submédio do Vale do São Francisco (S.V.S.F.), located in the Brazilian Northeast, is an emerging winemaking region in South America. Touriga Nacional (T.N.) grapes originated in Portugal, thrive under the climatic conditions found in the S.V.S.F. The effects of extended maceration on different parameters of red wine must produced with T.N. grapes from two harvest years from S.V.S.F. were studied. Increased maceration time (16 to 20 days) resulted in greater total phenolic contents (40 to 85%) compared to eight days of maceration, along with higher antiradical activity (15 to 36%). Regardless of the harvest year, the antiradical activity was mostly related to the contents of resveratrol, (+)-catechin, isorhamnetin-3-O-glucosidase, and (?)-epigallocatechin gallate. In contrast, color intensity was not affected. The increase in the maceration period induced a positive effect on the phenolic composition, which was reflected in the higher antiradical activity of T.N. red wine