Abstract:

Investigation of the appearance and elimination of “pinking” phenomenon in white wines is presented in the paper. Several factors that can cause pinking were analyzed: the degree of grapes ripeness and enzymatic treatment. The effect of fining agents based on polyvinylpolypyrrolidone (PVPP) on the elimination of “pinking” was determined. It was proved that pinking in wines decreases with an increase in the sugar content in grape. This is explained by a decrease in the content of anthocyanins at the end of technical ripeness of grape. Experimental studies  confirmed that the use of pectolytic enzymes with cellulase, hemicellulase, β-glucanase activities increases the intensity of straw color and the appearance of body tones, but does not affect pinking. Such treatment contributed to a slight increase in the content of phenolic compounds in wine materials, but did not affect the content of anthocyanins and  “pinking” susceptibility. Treatment of wine materials with complex PVPP-based agents including sorbents and flocculants, is an effective way to eliminate the “pinking” phenomenon. This reduces “pinking” in wine materials from 70…90 % to 1…2 %. This is due to the presence of sorbents and flocculants in the fining agents, which react with phenolic substances that cause “pinking” in white wines, and remove them from the system. So, there are reasons to argue that processing grape at the end of technical ripeness will contribute to a lower “pinking” susceptibility of wine materials; pectolytic enzymes did not affect the appearance of this phenomenon in white wines, and PVPP-based fining agents together with bentonite, activated carbon, gelatin or casein, are an effective way to reduce the “pinking” susceptibility of wine. Author Biographies Marina Bilko, National University оf Food Technologies Doctor of Technical Sciences, Professor Department of Biotechnology of Fermentation and Winemaking Products

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