Changes of some groups of phenolic compounds, color characteristics and antioxidant activity of red wine from Bulgaria as a result of bentonite and cold treatments

Abstract

The influence of bentonite and cold treatments on some groups of phenolic compounds, color characteristics and antioxidant activity of young red Cabernet Sauvignon wine from Bulgaria was studied. Bentonite was administered in increasing doses in the range of 0.2-1.6 g/L. The wine was chilled at -5 °C for 24 hours. The influence of bentonite on the index 280, phenolic complex and color characteristics was stronger when it was applied in doses of above 0.6 g/L, whereas antioxidant activity was more substantially affected at doses of above 1 g/L. Cold treatment led to greater changes in the studied indices of the composition and antioxidant activity of the wine in comparison to adding bentonite. It led to a decrease in the index 280 by 19 %, and the concentration of the studied phenolic complex groups decreased by about 6-7 %. Color intensity decreased the most of all studied indices. This index was reduced by about 32 %, without a significant change in the composition of its color and shade. The decrease in the content of phenolic compounds is probably the reason for the 23 % decrease in the antioxidant activity of the studied wine.