Comparative assessment of three yeast samples for wine production from pineapple

Pineapple is an abundant fruit in Nigeria, which usually suffers post-harvest spoilage due to lack of preservation techniques. Its rich sugar content makes it a suitable substrate for wine production, which becomes a useful alternative to curbing its post-harvest spoilage. This research compared the production of wine from pineapple using Saccharomyces cerevisiae, Saccharomyces bayanus, and Saccharomyces ellipsoides. Yeast viability was assessed on YPG medium. To each fermenting jar was poured sterilized 3000 ml must, comprising of a mixture of juice and 6 ml of each yeast inoculum. Sodium metabisulphite (0.4g/l) was also aseptically added to each of the fermenting jars as a preservative and the fermenting jars were sealed with corks. Fermentation was allowed for twenty-eight (28) days within which different physical analyses were carried out (pH, temperature, titratable acidity, specific gravity, reducing sugar, alcoholic content) for each day. Sensory evaluation of the finished products was conducted and the overall level of acceptance was determined. The viable counts of Saccharomyces cerevisiae, Saccharomyces bayanus, and Saccharomyces ellipsoides after growth on YPG medium were 3.3 x 106, 3.5 x 106, and 3.8 x 106 cfu/ml respectively. There was decreased pH, reducing sugar, and a specific gravity of the wine samples while, there was an increase in titratable acidity, alcohol content, and temperature. Significant differences (p<0.05) existed in the overall acceptability of the wine samples with S. bayanus fermented wine having the least acceptance by taste panelists. Pineapple makes a good compatible raw material for wine production using varying yeast samples.