Abstract:

A total of 71 strains of yeast were isolated from pomegranate leaves and rind as well as pomegranate garden soil. After 3 screening cycles, 2 strains, numbered as SL18 and SL20, were obtained, which were the most suitable for production of pomegranate wine. According to morphological observation and physiological and biochemical tests, the 2 strains were identified as Saccharomyces cerevisiae. In addition, the fermentation performances of this 2 strains and active dry yeast (Anqi brand) were compared. Results showed that when the fermentation temperature was 25 ℃, the fermentation cycle of strain SL20 was 1 day shorter than that of strain SL18 and active dry yeast, the alcohol degree was up to 9.7% (V/V) at the end of fermentation, and the wine product obtained was full-bodied and sterling. Although the fermentation cycle of strain SL18 was the same as that of active dry yeast, the wine produced by the former was more full-bodied and sterling than that produced by the latter. When the fermentation temperature was 30 ℃, all the three starters led to rapid fermentation at the early stage, the fermentation cycle of both strain SL18 and SL20 was 1 day shorter than that of active dry yeast, and the alcohol degree produced by strain SL20 was higher than that produced by strain SL18 and active dry yeast, reaching 10.1% (V/V), but for these three starters, the flavors of pomegranate wines produced by them was not more full-bodied than those produced by them when the fermentation temperatures were 20 and 25 ℃, indicating that strain SL18 and SL18 are more adapted to 25 ℃ fermentation and can endure alcohol degree of 12% (V/V), and the quality of the wine products produced by them is superior to that produced by active dry yeast.

Key words: pomegranates wine, yeast, screening, identification