The antioxidant activity of the products of processing of red grape of Cabernet Sauvignon, Merlot, Saperavi
AbstractExperimental data on the antioxidant activity of grape juice, grape concentrates and wine from grapes of Cabernet Sauvignon, Merlot and Saperavi from Crimea and Krasnodar regions was presented. Flavonoids are presented in the form of glycosides of such anthocyanins as delphinidin, malvidin, cyanidin, petunidin, peonidin and also by quercetin and its glycoside, (+)-D-catechin and (-)-epicatechin. Oligomeric procyanidins, which are condensed catechol units (2–6) soluble in water, are presented in significant amounts, and polymeric procyanidins with the amount catechin units greater than 7, insoluble in water, constituted the bulk of polyphenols od wine and concentrates from red grapes (no juice). Among non-flavonoid polyphenols hydroxybenzoic (gallic, syringic) and hydroxycinnamic (caftaric, сautaric) acids are identified, the relative content of which in the amount of polyphenols in the juice is maximum, and minimum is in concentrates. It was found that antioxidant activity for all products in standard Trolox method can be estimated by the equation: Y=0.53627+0.1395X+0.080439X2-0.00064708X3, with a correlation coefficient r=0.9952; where: Y – antioxidant activity, g/dm3 by Trolox method; X – mass concentration of phenolic substances on the Folin–Ciocalteu, g/dm3. The equation is valid for Y=0.76–196.22; X=1.0–82.67. The results of biological testing of wines Cabernet Sauvignon, Merlot, Saperavi and polyphenol concentrates from grape on the biological model of bioluminescent bacteria Photobacterium leiognathi Sh1 demonstrated the applicability of bioassay to assess the antioxidant activity, which correlates well with the polyphenols content and antioxidant activity by trolox method.
Keywords:grape polyphenols, antioxidant activity, bioluminescent bacteria, biotesting, wine, grape concentrates