The Influence of the Pretreatment by Pepsin in Fermentation of Soybean Yogurt

To manufacture the soybean yogurt using lactic acid bacteria,soybean was ground to powder,mixed with water to make soybean milk and then pre-hydrolyzed by pepsin at 37 ℃ for 30 minutes.Then,high-fructose corn syrup was mixed with the pretreated soybean milk until the sugar degree reached 6%.5% of lactic acid bacteria starter was inoculated to initiate the fermentation under anaerobic conditions at 38 ℃.The fermentation mixture was reserved at 4 ℃for 24 h as secondary fermentation.The pre-hydrolysis of the soybean powder by 0.5% pepsin for 30 minutes could shorten the fermentation time and improve total acids in the soybean yogurt.Using pepsin to pre-treat soybean to manufacture the soybean yogurt can save the time of fermentation and produce a delicious soybean yogurt.