Phenolic composition and physicochemical parameters of Carmenere, Cabernet Sauvignon, Merlot and Cabernet Franc grape seeds (Vitis vinifera L.) during ripening

Phenolic composition and some physicochemical parameters of seeds from grape cultivars (Vitis vinifera L) Carmenere (CA), Merlot (M), Cabernet Franc (CF) and Cabernet Sauvignon (CS) were evaluated at four different ripening stages. Compositional differences between cultivars were observed only in some ripening stages. Nevertheless, significant differences between CA and CF were observed throughout all the study period (veraison to harvest) in a number of parameters, including seed weight, total tannins and polymeric flavanol fraction. Each of the four grape varieties showed characteristic sets of colorimetric coordinates (CIElab parameters) at any of the ripening stages. On the other hand, while M seeds presented a high concentration of both (+)-catechin, (-)-epicatechin, epicatechin-3-O-gallate, proanthocyanidin trimers 1, B3 and B4, CA seeds presented characteristic high concentrations of a series of other proanthocyanidins. CF seeds displayed the highest concentrations of gallic acid and proanthocyanidin gallates. Altogether, we conclude that Carmenere, Merlot, Cabernet Franc and Cabernet Sauvignon grape seeds present marked differences in phenolic composition during ripening. (c) 2012 Elsevier Ltd. All rights reserved.