Phenolic composition of skins from four Carmenet grape varieties (Vitis vinifera L.) during ripening

Phenolic composition of skins from Vitis vinifera L. cv Carménère (CA), Merlot (M), Cabernet Franc (CF) and Cabernet Sauvignon (CS) grapes during ripening was evaluated by HPLC-DAD and spectrophotometric analysis. At the time of harvest maturity, CS skins showed the highest contents of monomeric, oligomeric and polymeric flavan-3-ols with respect to other varieties. Likewise, the L^*, C^* and a^* CIElab parameters showed no statistical differences between the four varieties but the H^* and b^* CIElab parameters exhibited clear differences between the M and CS skins. Alike, the sum of glucoside and cumarilglucoside anthocyanins in CA identified by HPLC-DAD was higher than in CF and CS in some sampling date. Additionally, significant differences in the content of low molecular weight phenolic compounds quantified by HPLC-DAD were observed. Comparatively, the CS skins displayed higher mDP, %EG and aMW values than the rest of the cultivars on the last sampling date. Overall, we conclude that CA, M, CF and CS grape skins present marked differences in phenolic composition during ripening.