This experiment was carried out to isolate osmophilic yeasts for higher concentration of NaCl than 20 per cent may affect greatly the fermentation of soy sauce. 6 strains of yeasts were selected from the soy sauce mashes at the fermentating periods and identified observing their morphological characteristics.
Their salt-resistance and effects upon the flavor of soy sauce were examined. The results obtained were as follows:
(1) The strain T₃,T_5, and T_(11), T_8, T_9, and T_(10), selected were identified Saccharomyces cerevisiae group Ⅱ, Debaryomyces nicotianae, Saccharomyces chevaliers, Saccharomyces rouxii and Saccharomyces roses, respectively.
(2) They were more salt-resistant on the liquid media than on the solid media in the case of cultures on the media containing more than 26 per cent of NaCl.
(3) They were grown on the media containing 5-23 per cent of NaCl better than containing none of NaCl.
(4) The strain T₃, T_8, T_9, and T_(10) were grown on the media containing up to 28 per cent of NaCl, and T_5 and T_(11) up to 32 per cent of NaCl is the case of liquid cultures.
(5) Among them, the strain T_9 showed the best alcohol fermentation ability and the best fermentative flavor, and T_5, and T_(11) formed moldy smell and pellicle.
|