Fruit wine produced from pawpaw (Carica papaya) and watermelon (Citrullus vulgaris) using Saccharomyces cerevisiae isolated from selected fermented foods

Abstract

This study was aimed at investigating the suitability of the fruits (pawpaw and watermelon) as substrates for wine production and the efficiency of yeast isolated from fermented foods for alcoholic fermentation of fruits. Yeast cells were isolated using pour plate technique. The probable isolates were confirmed using molecular procedure. The yeast cells were used to ferment pawpaw and watermelon Juice (must) to produce wine. During fermentation aliquot samples were removed daily from the fermentation tank for analysis of pH, temperature, total titrable acidity and total viable yeast counts were determined at 24 h interval. During wine production temperature ranged from 27 °C to 30 °C. There was a gradual decrease in pH (ranging from 4.4 to 3.3) and specific gravities (ranging from 0.99 to 0.84), with increase in titratable acidity (ranging from 1.53 to 2.23%) and alcohol contents (ranging from 0.0 to 13.63 %). Proximate composition revealed that fruit juices had higher percentage moisture content, ranged from 76.72% to 85.94%, ash content of 0.08% to 0.67%, protein content of 4.59% to 5.69%, percentage fat content of 7.35% to 8.75%, and total carbohydrates of 1.46% to 5.99%,while proximate composition of the produced fruit wine revealed percentage moisture content of 83.45% to 85.12%, ash content of 0.17% to 1.05%, protein content of 3.17% to 5.47%, percentage fat content of 7.45% to 830%, and total carbohydrates of 1.08% to 3.80% respectively. Microbial analysis and sensory evaluation of the produced wine was carried out using nine (9) point hedonic scales by 10 panellists, Sensory evaluation (P>0.05) rated the wines acceptability as Pawpaw wine > Watermelon wine > blend of Pawpaw and Watermelon wine. Shelf life assessment of the produced fruits wine were carried out and samples were plated on nutrient agar and sabouraud dextrose agar for enumeration of bacteria, using standard procedures. During shelf life assessment, it was observed that there were no spoilage or growth of microorganisms in wines samples at room temperature (26oC) and refrigeration temperature (4oC) except Saccharomyces cerevisiae. This study revealed that watermelon is the most acceptable wine and could be produced from this fruit with yeast from palm wine.