Study On Fermentation Of Soybean Milk By Lactic Acid Bacteria

Soybean yoghurt is an acid coagulated soymilk trod that is a raw material used for soybean production of lactic acid fermentation. In this paper, production process of soybean yogurt, the selection and domestication of lactic acid bacteria, beany flavor removal, optimization of fermentation conditions, preparation of tllc new health-care soybean yogurt and several aspects of the research and development have been studied as follows.Streptococcus thermophilus and Lactobacillus bzdgaricus were selected from the four lactic acid bacteria of laboratory for the production of fermented soybean milk, and the ratio of1:1was be identified. Two kinds of lactic acid bacteria were domesticated respectively.850C hot water with5minutes, quickly placed in cold water to cool it down, and then soaked10hours in0.25%NaHC03solution. Refining treatment with boiling water, soybean yogurt products with a very slight beany flavor, good organizational status and taste can be got.Through experiments, homogenization twice under450C,25MPa can significantly improve the stability of soybean milk.Through single factor experiments and orthogonal test, the optimum fermented conditions of soybean yogurt has been determined as fallows:1:1mixture of two kinds of lactobacillus added to soymilk, inoeUIUm size.4%, soybean: water=1:8, fermentation at400C for4h. Stabilizer was0.15%pectin+0.15%CMC-Na, suger was3%glucose+8%sucrose. The optimum fermented conditions of Sprouts milk has been determined as fallows: Using three-day soak bean sprouts as raw materials to fermented,1:1mixture of two kinds of lactobacillus added to soymilk, inoculum size4%, soybean: water=1I:8, fermentation at400C for4h. Stabilizer was0.15%pectin+0.15%CMC-Na, suger was3%glucose+8%sucrose.The changes of nutrients during the process of fermentation were determined. Amino acids, fat, reducing sugar were Change accordingly.Through orthogonal tests, the optimum process formula and technology have been determined as follows:1:1mixture of two kinds of lactobacillus added to soymilk, inoculuni size4%, added Toona sinensis juice15%, Sucrose5%, Glucose2%, Pectin0.15%., fermentation at400C for4h, The fermented product with mixed fragrance of Toona sinensis and soy bean can be obtained. All quality indexes meet the national standard.