Preliminary Study On Influencing Factor Of Content Tea Polyphenols And Antioxidant Activity In Milk Tea Powder

TP (tea polyphenol) refers to the mixture of polyphenol contained in tea leaf, with strong antioxidant activity and medical efficacies, such as anti-cancer, anti-aging, anti-radiation, removing free radicals, regulating blood sugar level and preventing cardiovascular diseases. As a new type of antioxidant in food, TP has functions of preventing or deferring the oxidative deterioration of food components. This paper aims to conduct a comparison of the influence that different processing methods respectively exert on the content of TP in milk tea powders, and make relevant explorations on the TP content, antioxygenic property and sensory index of some kinds of brand milk tea powders, so as to specify the perfect brewing condition and understand the basic characteristics of TP in different brand milk tea powders. Research results show that:(1) Respectively brew milk tea powders in different water temperatures (50,60,70,80℃),and then measure TP content. The perfect brewing water temperature is specified as70℃, and at this time, the highest TP content in milk tea powder is3867.03mg/kg. Lay aside the brewed milk tea powder (respectively for10,20,30,60min). As the laying time increases, TP content is gradually decreasing.(2) The shelve life of milk tea powder at ambient temperature affects TP content. TP content decreases as shelve life increases.(3) The milk tea powder of four available brands in market-Mengniu, Xiangpiaopiao, Youlemei and Menggu Eji is respectively measured, and their sensory indexes are assessed. Results show that TP content is Menggu Eji> Mengniu> Xiangpiaopiao> Youlemei; both their TP contents and sensory indexes are in conformity with the stipulation of 《GB21733—2008》in relation to tea drinks.(4) The removing capacity of the TP contained in four kinds of brand milk tea powders on DPPH has been respectively measured. As the sample concentration increases, the removing capacity tends to rise. When it comes to a same concentration, the removing capacity of TP on DPPH is Menggu Eji> Mengniu> Xiangpiaopiao> Youlemei, among which TP content in Menggu Eji mile tea powder is highest, and so is its removing capacity.