Biotechnological Studies on the Fermentation and Physicochemical Characterization of Palm Fruit, Tiger Nut, and Watermelon Juices for Wine Production

This study investigated the fermentation potential of juice blends derived from palm fruit (Phoenix dactylifera), tiger nut (Cyperus esculentus), and watermelon (Citrullus lanatus) for wine production. The formulation involved blending different volumes of juice from the fruits, with the addition of a sugar solution, Saccharomyces cerevisiae, and nutrients (ammonium phosphate and potassium phosphate) to support the fermentation process. Primary fermentation was conducted over six days in airtight containers. This was followed by a secondary fermentation phase lasting fourteen days under anaerobic conditions. The results showed that during primary fermentation, wine samples exhibited notable fluctuations in temperature and pH. Temperature readings across all samples peaked on day three, ranging from 29.0°C to 30.2°C, before declining to 26.1°C to 27.5°C by day six. Single-matrix juices displayed slightly lower initial temperatures (26.4°C to 27.0°C) compared to blended juices, which started between 28.0°C and 28.2°C. The pH values consistently decreased over the six-day fermentation period, from an initial range of 3.74 to 4.80 to a final range of 3.00 to 3.13, with blended juices showing a more pronounced pH drop (4.80 to 3.13) than single-matrix juices (3.74 to 3.01). After secondary fermentation and clarification, the final temperatures of the wine samples ranged from 27.0°C to 28.1°C. Specific gravity values ranged between 0.8932 and 1.0002, indicating near-complete sugar utilization. The final pH values were between 2.88 and 3.89, alcohol content varied from 14.63% to 15.66%, and total titratable acidity ranged from 0.54% to 0.65%. This study concluded that all wine samples underwent a successful fermentation and all exhibited physicochemical properties which are within the standard of commercially acceptable wines, with wine gotten from date palm fruit and watermelon having the most balanced physicochemical profile. Recommendation included adopting the insight from this study to remedy the excessive wastage of fruit around the world.