Ripening-associated flattening out of inter-varietal differences in some groups of phenolic compounds in the skins of six emblematic grape wine varieties

Abstract

The sensorial quality of wine grapes largely depends on the phenolic composition. Malbec, Tempranillo, Sangiovese, Petit Verdot, Cabernet Franc and Carménère are emblematic Vitis vinifera red grape varieties for wine-producing valleys around the world. This study aimed to characterize the phenolic composition (total phenols, tannins and anthocyanins, size-based proanthocyanidin fractions, anthocyanidin conjugates and low molecular weight phenolics) of grape skins from those alien varieties grown in Chile under common edaphoclimatic and cultural conditions throughout ripening. Some marked quantitative intervarietal differences were observed at corresponding phenological stages. Exceptionally, some compounds were either overexpressed (cyanidin glucoside) or not expressed (conjugated anthocyanidins) in single varieties. Despite those differences, ripening was characterized by a striking intervarietal assimilation (lower variation coefficients) mostly concerning the group of low molecular weight phenolics. Such intervarietal convergence suggests that the emblematic character can depend on the varietal gene pool and its interactions with a specific terroir and local cultural practices.