Quality Assessment of Water Melon ( Citruluslanatus ) Wine Produced Using Saccharomyces cerevisiae Isolated from Palm Wine

Abstract

This study was aimed at investigating the suitability of water melon juice as substrate for wine production and the efficiency of Saccharomyces cerevisiae isolated from palm wine for alcoholic fermentation of the juice. The yeast was isolated using pour plate technique and was identified using sugar utilization test, screened for ethanol tolerance test and was finally identified using API 20C AUX kit, as Saccharomyces cerevisiae. The yeast was purified and used to pitch water melon must using 0.5 McFarland standard and was allowed to undergo fermentation for three (3) days. Variations in temperature, pH, total titrable acidity, volatile acidity and total yeast count were determined at 6 hour intervals. The must and the produced wine were subjected to proximate and physico chemical analysis. The produced wine was subjected to microbial and sensory evaluation using seven point hedonic scales by 10 panelists. A total of 19 yeasts were isolated but only 5 isolates were suspected to have the same colony morphology as Saccharomyces cerevisiae after microscopy. The isolates assimilated mainly glucose, maltose and sucrose, but not fructose, lactose and mannitol. The ethanol tolerance was found to be between 2- 8% ethanol tolerant. The temperature ranged between 25- 30°C. The pH and volatile acidity decreased while total titrable acidity increased as the fermentation progressed. The total yeast count ranged between 1.9 - 8.2 × 107CFU/mL. Results of the proximate composition showed that there were significant difference (p 0.05) for taste between the two wines. This study revealed that a tropically available fruit in Nigeria like water melon is suitable for fruit wine production with Saccharomyces cerevisiae from palm wine, with high acceptability and good microbiological standard.