WINE PRODUCTION FROM SOURSOP USING GENETICALLY-IDENTIFIED Saccharomyces Cerevisiae ISOLATED FROM PALM WINE

Abstract

The need to indigenize the raw material base for wine production in Nigeria especially the source of juice and yeast starter cultures cannot be overemphasized. Studies were carried out on wine production from soursop fruit using genetically-identified Saccharomyces cerevisiae isolated from palm wine. Soursop juice (1,000ml) was used to produce wine through the following procedures; extraction, fermentation, racking, stabilization, pasteurization, ageing and maturation. The juice was fortified with 100g of granulated sugar to raise the sugar level. Sodium metabisulfite (2.0g) was added to treat the must against microbial attack. Fermentation commenced after pitching 1,000ml of sterile juice with 150ml of yeast biomass. Primary fermentation and secondary fermentation lasted for 7 and 14 days respectively. Physicochemical, microbiological and organoleptic analyses were carried out on the wine sample produced. The pH, specific gravity and sugar level of the fresh “must” prior to fermentation was 4.2, 1.069 and 17^oBrix, respectively. The result of the physicochemical analysis of the wine sample showed that the specific gravity, %alcohol (v/v), total acidity as acetic acid, pH and sugar level were 0.9800, 9.5%V/V, 0.8945%, 3.6 and 1.8^oBrix, respectively. The result of bacteriological analysis showed colony count of the isolates as 2.0x10^-3cfu/ml. Organoleptic evaluation result of the wine sample after one month storage showed that the appearance of the wine sample ranked more than its taste and aroma and it was generally accepted at 95% confidence level. These results show that wine of acceptable organoleptic quality can be produced from soursop fruits.