Comparative Study of the Phenolic Composition of Seeds and Skins from Carmenere and Cabernet Sauvignon Grape Varieties (Vitis vinifera L.) during Ripening

The phenolic composition of skins and seeds from Vitis vinifera L. cv. Carmenere and Cabernet Sauvignon grapes during ripening was evaluated by high-performance liquid chromatography-diode array detection and spectrophotometric analysis. As compared to Cabernet Sauvignon grape skins, Carmenere grape skins presented higher contents of total anthocyanins, monomeric flavan-3-ols, and total flavonoids, a higher mean degree of polymerization, a higher percentage of galloylation, a higher average molecular weight of the flavanol fraction, and a higher color intensity. As compared to Cabernet Sauvignon grape seeds, Carmenere grape seeds presented a lower content of monomeric flavan-3-ols, a higher mean degree of polymerization, a higher percentage of galloylation, a higher average molecular weight of the flavanol fraction, a lower content of (+)-catechin, and higher contents of (-)-epicatechin, epicatechin-3-O-gallate, gallic acid, and dimeric procyanidins esterified with gallic acid. Altogether, we conclude that Carmenere grapes present a differential composition and evolution of phenolic compounds when compared to Cabernet Sauvignon grapes.