Phenolic composition and free radical scavenging activity of wine produced from Serbian autochtonous grape variety Prokupac: A model approach

Abstract

Phenolic compounds are very important quality parameters of wine because of their impact on colour, taste and health properties. The present study aimed to evaluate the general phenolic composition and free radical scavenging activity of aqueous and organic fractions obtained using liquid/liquid extractions from red wine produced from Serbian autochtonous grape variety Prokupac. Total phenolic contents in different fractions ranged from 48.22 to 289.12 mg GAE/g dry fraction. Phenolic acids (mainly hydroxycinnamic acids) and quercetin-3-glucuronide were the main components of the EtOAc fraction at pH 2.0; catechins, phenolic acids (mainly hydroxybenzoic acids) and quercetin were found in the EtOAc fraction at pH 7.0, while anthocyanins were identified in the aqueous residue after EtOAc extraction. The major anthocyanin extracted into aqueous fraction was malvidin-3-glucoside, while the most abundant non-anthocyanin phenolic compounds from organic fractions were ethyl gallate and trans-caftaric acid. Radical scavenging activity differed significantly among fractions and IC50 values were 138.58 ?g/ml for water fraction, 17.83 and 3.47 ?g/ml for EtOAc fractions at pH 2.0 and pH 7.0, respectively. As the EtOAc fractions were found to be more potent radical scavengers, it could be assumed that non-anthocyanin phenolic compounds were responsible for such activity in Prokupac wine.