Influence of initial Tannin concentration in must on the kinetics of wine fermentation, using yeast immobilized in calcium alginate gel

Abstract

This study investigated the effects of five initial tannin contents (1.8, 2.8, 3.8, 9.8 and 17.8g of acid tannic/L) on the kinetics of red wine fermentation, using yeast immobilized in calcium alginate gel. Our experimental results showed that in the medium with high tannin content (9.8 and 17.8g of acid tannic/L), maximum cell density and maximum specific growth rate of the immobilized cells were higher than those of the free cells. In all cases, the glucose utilization rate and ethanol production rate of the immobilized yeast were always higher than those of the free yeast. Moreover, using immobilized yeast in wine fermentation decreased pH value and volatile acidity of the culture. Thus the colloidal and biological stability and the organoleptic characteristics of the final product were ameliorated.