Abstract: Kefir grains, the conventional culture of kefir, were used in this test as culture starter for fermenting the mixture of soy bean and fresh cow milk. With the orthogonal experimental test, the optimum fermentation conditions for preparing soy kefir, a new kind of ferment soybean, were screened out. The ratio of soy and cowmilk as (8:2), addition of 3% inoculant 10% sucrose as the milk basis and fermentation under 25℃ for 14h, were the optimuim conditions for preparing the soy kefir with an acidity of 83°T and ethanil content of 0.26%.

Key words: soybean, kefir grain, fermentation, soy kefir