The ability of various yeast strains to ferment alcohol from waste rambutan (Nephelium lappaceum Linn) fruit

Abstract

Alcohol is the raw material used in the manufacture of vinegar, it can be distilled to make liquor, and refined alcohol can be used to produce ethanol as an energy source. Raw materials containing sugar, fermented with yeast, are the source of alcohol. Rambutans are fruits containing high content of sugar. After harvesting, the outside appearance of rambutans is no longer acceptable by customers because the fruit deteriorates rapidly within three to five days, resulting in decreasing value. In this research, we aimed to investigate the use of low-quality rambutans for fermentation to produce alcohol. Four single strain, two mix strains, and three combination strains of yeast (Saccharomyces cerevisiae) were used in alcohol fermentation of low-quality rambutans. The alcohol content was evaluated every day for 14 days after fermentation. The results showed that for the single strain of S. cerevisiae, the TISTR 5020 could produce the highest number of alcohol content at 11.4% after fermented 11 days, followed by the TISTR 5596 strain, which gave 10.8% alcohol on day 8. For the two mix strains of yeast, the combination between TISTR 5596 and TISTR 5194 as well as the combination between TISTR 5094 and TISTR 5596 could provide the best result at 10.5% alcohol on day 9 and day 11 respectively. In the three combinations of S. cerevisiae, the combination of TISTR 5596, TISTR 5194 and TISTR 5094 could produce 11.0% alcohol after fermented for 14 days while the mixture of TISTR 5094, TISTR 5020 and could provide 10.8% alcohol on day 4.