INFLUENCE OF VARIOUS TECHNOLOGICAL FACTORS ON THE COMPOSITION OF ANTHOCYANINS IN BLACK CURRANT WINE PRODUCTION

Anthocyanins obtained from raw fruit have valuable biological and antioxidant properties, hence the relevance of any research aimed at the development of technological solutions for their maximum preservation in wine. The present research features the changes in qualitative and quantitative composition of anthocyanins found in black currant during wine production with the use of enzymatic maceration of the pulp. The authors determined the most effective ways of increasing the concentration of anthocyanins in the finished product. They used the method of pH-differential spectrophotometry to evaluate the total content of monomeric anthocyanins in the samples and the HPLC method to determine the concentration of individual anthocyanins. The DPPH and ABTS methods were used to measure the antioxidant activity. The pulp of black currant was treated according to four schemes: 1) heat maceration; 2) heat maceration with enzymatic treatment; 3) enzymatic maceration at the optimum temperature for enzyme activity; 4) enzymatic maceration at a low temperature. Eleven anthocyanins were identified in the black currant juice, most of which were glycosides of delphinidin and cyanidin. The highest extraction of anthocyanins was observed when the pulp was processed with the help of Fructozim Kolor enzyme preparation at 22–23°C during four hours. As a result, the proportion of delphinidins decreased while the proportion of cianidins rose by 9%. When the pulp was heated to ≥ 45°C, it led to an intensification of the redox process and formation of insoluble complexes of anthocyanins with the nitrogenous compounds, which reduced the total concentration of anthocyanins. It was established that in the process of fermentation, the anthocyanin concentration decreased by 19–58%, depending on the race of yeast. For fermentation of blackcurrant wort, the authors recommend the following races of yeast: Moscow 30, Blackcurrant 7, and UWY SP1. The research revealed that the antioxidant properties of black currant wort and wine increased when the total concentration of anthocyanins was high.