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.

Highlights

  • In some white wines, a pink tinge with different intensities may appear during production and storage

  • The mechanism for the appearance of this phenomenon and the substances that cause it have not yet been determined, there are some hypotheses. Understanding these processes is important because the appearance of pink tinges in the color of white wines indicates the beginning of oxidation, deviation

  • After the test for the “pinking” potential, the analysis of the results showed that with increasing sugar content of grape, the pinking susceptibility of wines decreases (Fig. 1)

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Summary

Introduction

A pink tinge with different intensities may appear during production and storage. This problem appeared about 30–40 years ago and winemakers around the world have been taken it seriously [1–3]. During this period, scientists from different countries were finding out the causes of pinking. The mechanism for the appearance of this phenomenon and the substances that cause it have not yet been determined, there are some hypotheses. Understanding these processes is important because the appearance of pink tinges in the color of white wines indicates the beginning of oxidation, deviation

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