Exploration Research on Effects of Tea Polyphenols on the Growth of Lactobacillus Bulgaricus

The effects of tea polyphenols on the growth of Lactobacillus bulgaricus was studied by determining the number of bacterium and the acid-producing ability.The results show that the inhibiting effect of tea polyphenols on Lactobacillus bulgaricus grown in milk decreased as the contents of tea polyphenols decreasing.As the contents of tea polyphenols increase,the number of bacteria increases but then decreases at the same fermentation time,and the number of Lactobacillus bulgaricus reaches the largest at the content of tea polyphenols of 2.0 g/L.As the fermentation time increases,the acidity of milk increases gradually at the same content of tea polyphenols at the beginning,while it is going to be stable later.When the content of tea polyphenols is 2.0 g/L,the acidity is the highest.During the late fermentation period,the morphology of Lactobacillus bulgaricus is very unstable and a large of them decays.When the content of tea polyphenols is over high,the acid-producing ability of Lactobacillus bulgaricus is decreased and the color of yogurt is affected by the color of tea polyphenols.