Effect of recycled yeast inoculum on fermentation and quality of red wine produced from Punjab purple (Syn H516) grapes

Abstract

Fresh and recycled yeast (Saccharomyces cerevisiae MTCC 11815) inoculums were compared for fermentation of Punjab purple (Syn H516) grapes juice for preparation of red wine. An inoculum size of 10% of recycled yeast was optimized for an ethanol production of 9.5% (v/v) at a fermentation efficiency of 74.53% with stored juice and the same was consistent for up to two recycling lots. The prepared wine was allowed to sediment for 7 days at 4^oC, siphoned and filtered and then matured for 6 months in amber colored bottles. A significant decrease in ethanol, total phenols and yeast count was observed in wines prepared from both fresh and recycled yeast inoculum during storage. Both the type of wines scored 65.9±8.01 and 63.3±8.52 on sensory analysis for fresh and recycled inoculum, respectively and were significantly better than a commercial red wine. The red wines were also found to be rich in 10 amino acids.