FLAVONOL PROFILES FOR VARIETAL DIFFERENTIATION BETWEEN CARMENERE AND MERLOT WINES PRODUCED IN CHILE: HPLC AND CHEMOMETRIC ANALYSIS

Abstract

Wine differentiation is an important issue for the Chilean winemaking industry, especially for the Carmenere variety, which was rediscovered in this country around 20 years ago. Authentication parameters are required for this wine due to its frequent confusion with Merlot. The concentration of anthocyanins, shikimic acid, and the principal flavonols found in wine allowed some varietal differentiation between Carmenere and Merlot wines. Myricetin and quercetin are the most concentrated flavonols in wine in which they are present in free and conjugated forms. These compounds are responsible for important wine antioxidant properties. In the present work, using only the concentrations of free and conjugated quercetin and myricetin, differentiation between Carmenere and Merlot varieties was better achieved. Flavonol profiles of wine produced in Chile were studied with HPLC-DAD-ESI-MSn. An overview of the concentration range of flavonols present in 248 Chilean red wines is presented, finding that the mean concentration of the sum of total myricetin and total quercetin were higher in Carmenere (81.5 mgL(-1)) and Merlot (78.9 mgL(-1)) than in Cabernet Sauvignon (53.9 mgL(-1)) wines. These mean levels were higher than the majority of the concentrations reported in the literature. The chemometric analysis shows that the ratio of total quercetin/total myricetin combined with the concentration of free myricetin allowed the varietal differentiation between Carmenere and Merlot wines.