The separation and identification of lactic acid bacteria from fermented tofu whey and the application of the strains to ferment tofu whey

• 1、State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China

Abstract：Fermented tofu whey (FTW) is a traditional tofu coagulant used extensively in China. In order to acquire tofu biological coagulant, lactic acid bacteria were isolated from naturally fermented tofu whey. The analysis of 16S rDNA gene sequence demonstrated that these strains were identified as Lactobacillus fermentrum, Lactobacillus paracasei，Lactobacillus plantarum, Lactobacillus delbrueckii, Lactobacillus mucosae and Lactobacillus parabuchneri. L.plantarum were considered with high producing acid ability by monitoring the pH values during fermentation. Then L.plantarum was applied to ferment fresh tofu whey to prepare FTW. The results showed that large amount of organic acids were produced as the fermentation was prolonged during the 24h fermentation at 37℃. Lactic acid was the major organic acid in the FTW, which increased extensively during the process. The L.plantarum is of great ability to convert isoflavones glycoside into aglycones and utilize sucrose, raffinose and stachyose, which provides a good theoretical basis for the preparation of tofu biological coagulant by lactic acid bacteria.

Keywords： Lactic acid bacteria Fermented tofu whey Organic acid Soy isoflavones Tofu