The impact of hawk tea supplementation on properties of stirred yogurt

Milk was cultured at 42 ℃ for 7 h to obtain completely curdled,after sterilization,cooling and inoculation.Then the hawk tea concentrates were added to the milk at the rates of 0.2~1 m L/100 m L. The stirred hawk tea yogurt(SHTY) was obtained through mixing the hawk tea concentrate with the yogurt and stirred evenly. The stirred hawk tea yogurts were refrigerated at 8 ℃ for 5 weeks,and the effects of hawk tea concentrates on the properties of flavor,physicochemical,and lactic acid bacteria were evaluated. Results showed that the stirred hawk tea yogurt tasted good,and possessed the unique flavor of hawk tea. The properties of physical,chemical and lactic acid bacteria complied with the regulations of GB 19302. Compared to the control,the content of tea polyphenol,the capacity of water holding and the viscosity increased in varying degrees. Hawk tea concentrates promoted Streptococcus thermophilus growing,however,no significant effect was observed on Lactobacillus rhamnosus,Lactobacillus acidophilus,Lactobacillus casei and Lactobacillus delbrueckii subsp. bulgaricus.