牦牛酸乳分离乳杆菌发酵豆浆理化特性的研究

Study on Lactobacillus fermentum isolated from yak yogurt fermented soybean milk in physicochemical properties

探讨了牦牛酸乳分离乳杆菌(LFYY)发酵豆浆的理化性质。LFYY在人工胃液中存活率和在胆盐中的生长率为保加利亚乳杆菌(LB)的大约4倍和7倍。在6h和12h发酵后,LFYY发酵豆浆的pH高于混合菌(LM,LFYY∶LB=1∶1)发酵豆浆,LB发酵豆浆为最低。这些发酵豆浆的酸度呈现和pH相反的趋势。当发酵到6h和12h时,LM发酵豆浆中的总菌数高于LFYY和LB发酵豆浆。LFYY发酵豆浆中的氨基酸态氮和活性大豆异黄酮(大豆黄素和金雀异黄素)接近于LM发酵豆浆,显著高于LB发酵豆浆(p<0.05)。LFYY和LM发酵豆浆的感官品质也优于LB发酵豆浆。从实验结果可以看出,LFYY发酵豆浆的品质优于LB发酵豆浆,混合菌可以提高发酵豆浆的品质,牦牛酸乳分离乳杆菌有利于发酵豆浆的生产。

The present study aimed to investigate the physicochemical properties of Lactobacillus fermentum isolated from yak yogurt（LFYY） fermented soybean milk. The artificial gastric juice survival and growth rate in bile salt of LFYY were about four and seven times higher than Lactobacillus bulgaricus（LB）. The pH of LFYY fermented soybean milk was higher than mixture bacterial strains（LM, LFYY：LB=1：1） fermented one,and LB fermented soybean milk showed the lowest pH after 6 and 12h fermentation. Total acidity of these fermented soybean milk showed the opposite trends with the pH. In the fermentation process at 6h and 12h,the counts of Lactobacillus in LM fermented soybean milk were more than LFYY and LM fermented soybean milk. The amino type nitrogen content and activity of isoflavones（daidzein and genistein） in LFYY fermented soybean milk were close to LB one,and more than LM one（p〈0.05）. The sensory qualities of LFYY and LM fermented soybean milk were also better than LB one. From there results, LFYY fermented soybean milk showed the better qualities than LB one,the LM could increased the qualities of fermented soybean milk. Lactobacillus fermentum isolated from yak yogurt is good for fermented soybean milk produce.