Effects of Fermentation Time and pH on Physicochemical Parameters of Wine Must Produced from Hot Water Extract of Rauvolfia vomitoria Afzel Leaf using Saccharomyces cerevisiae

Abstract

The effects of fermentation time (Day 1 to Day 14) and pH (3.5, 4.5, 5.5, 6.5 and 7.5), on wine must physicochemical characteristics made by using hot water extract of Rauvolfia vomitoria Afzel leaf using Saccharomyces cerevisiae were studied. Yeast nutrient (Diazanium sulphate and magnesium salt) was added to the mixture and granulated sugar (sucrose) was used as the fermentation substrate. pH was measured with a pHep pocket-sized pH meter, using a portable refractometer, the total soluble solid (°Brix) was determined, and the amount of alcohol was determined using the potential alcohol difference approach. Results show that the alcohol content increased progressively and remained constant from day 6 (0.474 ± 0.000%) till day 14. Total soluble solids decreased, while from day 1 to day 14 of the must's fermentation, the pH increased and decreased. Similarly, the highest amount of alcohol (2.400 ± 0.000%) was produced at pH 5.5, while the lowest (0.592 ± 0.000%) was at pH 6.5 and pH 7.5. The study shows that the highest percentage of alcohols was obtained at pH 5.5 and at day 6 of fermentation. For the organism to produce the highest amount of alcohol, the fermentation period and pH of the fermenting media must be adjusted appropriately.