Wine Production by Guava Piece Immobilized Yeast from Indian Cultivar Grapes and its Volatile Composition

Suitability of guava pieces for the preparation of immobilized yeast biocatalyst for wine production was investigated by using Saccharomyces cerevisiae in repeated batch fermentation. The fermentation rate and other parameters were compared with free yeast cells at different temperatures. The volatile compounds, methanol, ethyl acetate, 1-propanol, isobutanol and amyl alcohols which, formed during fermentation were analyzed with the help of GC-FID. The concentrations of ethyl acetate and methanol were not more than 100 mg L-1 in all cases, indicating an improvement in the product. There are no changes in cell metabolism of immobilized yeast. Preliminary sensory tests established the fruity aroma, fine taste and the overall improved quality of the produced wines.