From Grape to Wine: Influence of Winemaking on Phenolic Profile and in vivo Antioxidant Activity.

LINGUA, M.; FABANI, M.P.; WUNDERLIN, D.A.; BARONI, M.V.

Praga

Congreso; Food Integrity 2016; Assuring the Integrity of the Food Chain; 2016

FOOD INTEGRITY - UNIVERSIDAD DE PRAGA

Phenolic are components ofwine with a great impact on its sensorial characteristics, especially colourand flavour. They have also shown beneficial effects on human health,protecting against cardiovascular and degenerative diseases. Severalfactors, including grape variety, grape ripeness, environmental factors and technologicalprocedures used during winemaking, can qualitatively and quantitatively affectthe phenolic composition of the grape and wine and, therefore, theirnutritional and quality properties. In this sense our main goal was to assess the effects of the winemaking technology on phenolicprofile of grapes and wines and the influence of these changes on the in vivo antioxidant activity (AC), considering three main varieties produced in Argentina: Merlot, Syrahand Cabernet Sauvignon. Grapes and wines samples were collected from thesame vineyard in the Province of San Juan, Argentina. In vivo antioxidantactivity was determined usingthe yeast Saccharomyces cerevisiae exposed to H2O2 as anoxidizing agent. The antioxidant activity was evaluated by measuring thesurvival rates of yeast and changes in antioxidant enzymes: GlutathioneReductase (GR) and Glutathione Peroxidase (GPX). Forty-fivecompounds, including anthocyanins, flavonols, flavanols,phenolic acids and stilbens, were identified by HPLC-PDA-ESI-MS/MS.Results show that phenolic composition and antioxidant activity vary along thewinemaking process and between varieties. In vivo AC demonstrated that yeast previously incubated with grape and wine polyphenols showed enhanced resistance to H2O2.Furthermore, GR and GPx activities were positively correlated with thechemopreventive effect observed. Dataobtained was analysed by multiple regression analysis (MRA) in order to evaluatethe relationship between phenolic profile and AC of grapes and wines. Resultsfrom MRA analysis showed that Syrah had the highest AC, because of theirphenolic profile characterised by the highest content in anthocyanin compounds,while the content of trans-resveratrol in Merlotgrapes and wine probably contributes to its lower activity. Furthermore, changesin the phenolic profile from grape to wine, because of the winemaking process,affected the AC. In this sense, grapes were characterised by higher content of kaempferol-3-glucosideand fertaric acid that may contribute positively to its higher invivo AC.On the other hand, ethyl gallate contributed negatively to the AC of wines. Resultspresented in this study underline differences in phenolic profile and invivo antioxidantactivity of products involved in the winemaking process: grape as a rawmaterial, wine as a final product. Furthermore, ourresults suggest that the AC of wine depends upon the grape variety used, sinceit largely determines the qualitative and quantitative composition inpolyphenolic compounds.