Effects of Addition of Different Carbohydrates on the Growth Characteristics of Kefir Grains in Soymilk

The effects of added glucose, lactose, and sucrose on microbial growth, acid and ethanol production, and galactosidase activity in soymilk fermented with kefir grains were studied. Immediately after the addition of kefir grains to soymilk, the lactic acid bacterial counts were higher but the yeast counts were lower than in milk kefir. After fermentation for 32 hr, the concentrations of yeast, lactic acid, and ethanol in soymilk were significantly lower than those in milk kefir. The addition of 1% glucose to soymilk stimulated growth of lactic acid bacteria and yeast, the production of lactic acid and ethanol, and the £)- galactosidase activity. Nevertheless, β-galactosidase activity was suppressed by 1% glucose.