FEATURES OF THE DETERMINATION OF DIHYDROXYLATED ANTHOCYANINS IN WINES

Abstract

The results of the investigation of the complexation of Al 3+ with anthocyanins of red wines (cyanidin-3-O-glucoside and delphinidin-3-O-glucoside) present in the work. By examples of delphinidin-3-O-glucoside and pelargonidine-3-O-glucoside, only dihydroxylated forms of anthocyanins are capable of forming a complex with Al 3+ , while non-hydroxylated anthocyanins of such complexes can not form. In the selected conditions, the total contents of dihydroxylated anthocyanins in wines made from different grape varieties (in terms of cyanidin-3-O-glucoside) are determined, which vary for red wines from 8.7 mg/dm 3 for Cabernet Kuban Vine Company to 27.1 mg/dm 3 for wine made from the Saperavi grape variety. The greatest contents of these forms of anthocyanins were obtained for wines made from the grape varieties of Saperavi, Krasnostop and Cabernet. To determine the relationship between dihydroxylated anthocyanins and monomeric forms, the total content of monomeric forms of anthocyanins in the investigated wines is determined by the method of pH-differential spectrophotometry. It was found that the share of these forms of anthocyanins in the total content of monomeric forms was 9 – 14 %. Between the total contents of dihydroxylated and monomeric forms of anthocyanins, a high degree of correlation was obtained ( r c = 0.98; r t = 0.63 for n = 10; α = 0.05). The relationships between the total contents of anthocyanins (both monomeric and dihydroxylated) with spectral characteristics (color intensity and shade) were determined by the recommended IOVV in evaluating the quality of wines. It is shown that for wines with the highest content of dihydroxylated and monomeric forms of anthocyanins, higher color intensities are characteristic.