Abstract: Germinated soybean yogurt was prepared by using skimmed milk powder and four-day germinated soybean as raw materials. Product quality was evaluated through sensory evaluation. Germinated soybeans were mixed with water at a ratio of 1:4.5 (m/m) and homogenized to obtain soybean homogenate. Skimmed milk powder was dissolved in a 5-fold volume of water, and mixed with the germinated soybean homogenate, followed by sucrose addition, inoculation and fermentation with mixed lactic acid bacteria. The fermentation conditions were optimized by orthogonal array design, and the results showed that the optimal preparation process for germinated soybean yogurt was sequentially composed of mixing of milk liquid with soybean homogenate (60:40, m/m) and sucrose (6 g/100 mL of soybean homogenate), inoculation with mixed lactic acid bacteria (5 mL per 100 mL of soybean homogenate), and fermention for 7 h. The effect of post-ripening on product flavor was also studied, which revealed that the optimum flavor was obtained after storage at 4℃ for 16h. The germinated soybean yogurt prepared by this method had the characteristic flavor of concentrated yogurt.

Key words: germinated soybean, yoghurt, ratio, fermentation conditions