Avaliação do potencial antioxidante, extração e quantificação de compostos fenólicos em sucos de uva produzidos no sudoeste do Paraná

Abstract

Grape juice has a high concentration of phenolic compounds, which are responsible for different biological activities, including antioxidant activity. There are studies in the literature with juices produced in different regions of the country, however, there are not results with juices produced in the southwest region of Paraná. Within this context, this study aimed to develop an efficient analytical method to identify and quantify the major phenolic compounds present in grape juice produced in Salgado Filho - PR, as well as determine the antioxidant potential these juices. The grape juices analyzed were produced from Bordeaux grape, Vitis labrusca L. variety, and belonged to the harvests of 2009, 2010 and 2012. The determination of phenol compounds was performed first by Folin-Ciocalteu and in sequence, chromatographic method was developed to identify and quantify the major phenolic compounds present in the samples. The antioxidant activity was analyzed by three different methods, sequestration DPPH, ABTS radical capture and iron reduction method (FRAP). The juice with the highest quantity of phenolic compounds (2.6 ± 0.7 g EAG L-1) and higher antioxidant activity by the three methods, 10.2 ± 0.5 mmol Trolox L-1 sequestration of DPPH, 12,2 ± 2.8 mmol-1 Trolox.L for ABTS and 7.5 ± 1.9 mmol Fe2+ L-1 FRAP was pertaining to the crop of 2012. Phenolic compounds identified in the samples were gallic acid, caffeic, coumaric, ferrúlico and t-resveratrol.