Phenolic compounds and antioxidant activity of three varieties of Argentinean red wines.

DI PAOLA, R.; BARONI, M.V.; OTAIZA, S.; RUIZ-SMANIA M; WUNDERLIN D.A.

Beauné

Congreso; WAC2011. Wine Active Compound; 2011

UNESCO Chair "Culture & Traditions of Wines" Beauné (Francia)

Phenolics are components of wine with a great impact on its sensorial characteristics, especially color and flavor. They have also shown beneficial effects on human health, protecting against cardiovascular and degenerative diseases. Some of these properties are directly related to their antioxidant activity. In this sense, the profile of phenolic compounds help to evaluate which compounds are mainly involved as free radical scavengers, acting as chemoprotectors that could be emphasized for dietary purposes. There are scarce reports about phenolic composition of Argentinean wines and their contribution to the antioxidant activity. Thus, we assessed the concentration of ten phenolics and the corresponding antioxidant activity in red wine samples, considering three main varieties produced in Argentina: Malbec, Syrah and Cabernet Sauvignon. The analysis of the profile of phenolic compounds was performed by HPLC-MS/MS. Further, free radical scavenging activity and ferric reducing power of the wines were evaluated by TEAC and FRAP method, respectively. The contribution of each phenolic compound to the antioxidant activity was evaluated statistically by a multiple regression model. Among phenolics analyzed, (+)-catechin and (-)-epicatechin were the most abundant for Malbec and Cabernet Sauvignon, while (+)-catechin and gallic acid were the main compounds for Syrah. Moreover, phenolic profiles showed minor differences between three wine varietals. All analyzed wines shown high antioxidant power, with the highest values for Malbec by the TEAC method and for Cabernet Sauvignon by the FRAP method. TEAC values correlated significantly with the amount of phenolic (r = 0.66). Coumaric acid was the compound presenting the highest positive contribution to the free radical scavenging (B = 1.25, p < 0.01). Likewise, caffeic acid show a negative correlation with this activity (B = -0.87, p < 0.01). On the other hand, FRAP method was highly correlated with the amount of phenolic compounds (r = 0.90). Kaempferol and myricetin shown a positive significant correlation (B = 1.00, p < 0.01; B = 0.32, p < 0.01), while quercetin, resveratrol and caffeic acid shown a negative correlation whit the reducing power of the wines (B = -0.73, p < 0.01; B = -0.53, p < 0.01; B = -0.38, p < 0.01; respectively). Results show that three groups of polyphenols, flavonols, phenolic acids and stilbenes are important predictors of both the scavenging activity and the reducing power in Argentinean red wines. More studies are underway to evaluate the contribution of other wine components to the antioxidant activity, their interactions and effects using in vivo models.