RO Ojo and EP Eniola
Watermelon (Citrullus lanatus) is the flowering plant species of the cucurbitaceae family. It is a highly cultivated fruit worldwide with more than 1000 varieties. The nutritional profile of watermelon is full array of nutrients including carbohydrates, soluble and insoluble fibre, sodium, vitamins, minerals, fatty acids, amino acids and many more.
Hence the need to investigate the suitability of watermelon juice as substrate for wine production and utilize yeast, Saccharomyces cerevissiae, to ferment the sugar present in the watermelon (fructose) to produce wine. The fruits were cut longitudinally into four parts and the seeds were removed with a sterile knife. The inner juicy part of the watermelon were removed, sliced and blended using an electric blender. The resulting slurry was filtered with a muslin cloth to obtain a clear pink liquid. Sodium metabisulphite (1%) was added on the first day of the fermentation as an antibacterial agent and to also inhibit wild yeast. 75 mLs of the starter culture and 30g of sugar was added and dissolved in water. Primary and secondary fermentation of the fruit juice lasted for 7 and 28 days respectively, during which aliquot samples analysis of pH, titratable acidity, specific gravity, alcohol content were measured using standard procedure. Specific gravity of the wine was observed to reduce drastically as the fermentation progresses. The pH of the must during the period of fermentation ranged from 3.0 to 4.96. During the fermentation period, consistent increase in alcohol content was observed with time. At the end of the 28th day of fermentation, the alcohol content was 3.2%. The titratable acidity of the wine was observed to show steady trend with time throughout the period of fermentation. The results shows that acceptable wine can be produced from watermelon using yeast (Saccharomyces cerevissiae) as the starter culture.
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