LU Rong-rong et al
In order to compare the effects of soy proteins and traditional fining agents on wine clarification and quality, 'Cabernet Sauvignon' dry red wine was selected as test material to study influence of five fining agents (soy protein, gelatin, bentonite, casein and PVPP) on clarity degree, physical and chemical indexes, color, phenolic and volatile compounds of sample wine. The results showed that transmittance of sample wines was increased and color intensity was decreased significantly after fining process (p<0.05). Total acids were decreased by -0.01-0.12 g/L, and volatile acids were increased by 0-0.06 g/L, but residual sugar, alcohol and hue had no significant change. Meanwhile, concentrations of total phenols, tannins, total anthocyanins, monomeric anthocyanins, polymeric anthocyanins and colored anthocyanins in treated sample wines were all lower than those of controls. And with increased dose of fining agents, their concentrations were decreased (except for polymeric anthocyanins). Among them, PVPP and gelatin had great influence on color and total anthocyanins of sample wines. In addition, aroma components in the wine samples were decreased after clarification. However, contents of volatile compounds especially esters in sample wine treated with soy proteins were obviously higher than those in other groups. In conclusion, high clarification degree, good color and aroma of sample wines treated with soy proteins of 200 mg/L indicated that soy protein could be used for the clarification of 'Cabernet Sauvignon' dry red wine.
