Received: 24-10-2013 / Accepted: 24-02-2014
The effects of yeast strains, fermentation temperature and pH on quality of Rhodomyrtus tomentosa wine were examined. At ambient temperature (28±2oC), the fermentation was induced by inoculation with Saccharomyces cerevisiae strains isolated, purified and screened from sugar palm (Borassus flabellifer) and pineapple juice in comparison with commercial yeast (initial populations of yeast raging from 104107 cells/ml). The medium was adjusted before fermentation to five different pH values (3.44.2). The effect of fermentation temperature (20 and 28±2°C) on strain population was also studied. The resulting wines were chemically analyzed. Pure cultures of Saccharomyces cerevisiae isolated from sugar palm significantly yielded in ethanol production higher than other strains in the fermentation at 28±2°C.. Yeast strains performed better at low temperatures with high alcohol yield. At 20±2°C, the fermentation was dominated by the growth of S. cerevisiae in Rhodomyrtus tomentosa juice with maximum ethanol concentrations (13.43%Vol.) The methanol and SO2 concentrations met the Vietnamese Standards (QCVN 6-3 2010/BYT). In addition, the total acid, ester and aldehyde concentration were also low.