Assessment of the Content and Stability of Tea Polyphenols, Free Amino Acids and Vitamin C in Four Kinds of Tea Beverages

The contents of tea polyphenols(TP),free amino acids(FAA)and vitamin C(V_C)in four kinds of tea beverages were analyzed. These tea beverages were stored at room temperature for 5 months. Their stability was investigated without opening in 5 months or after opening in 96 h. The results showed that the contents of TP,FAA and V_C were meeting the GB/T 21733-2008 in these beverages except in plain green tea beverage. The contents of TP,FAA and V_C decreased significantly under room storage in 5 months. TP contents decreased significantly at the third month(in September). V_C content decreased sharply in 1~3 months(from June to September). After 5 months,vitamin C was detected only in the flavored green tea, and no vitamin C was detected in the flavored black tea, the original leaf green tea, and the original black tea. The contents of TP,FAA and V_C also decreased significantly after opening in 96 h. V_C contents was very low after 72 h and V_C were not checked out after 96 h in black tea beverages. These results indicated that these tea beverages should not be stored under room temperature for long time,and the tea beverages after opening should be drunk in time. TP,FAA and V_C were the main ingredients in tea beverages. Focusing on their contents and stability in beverages could provide references for producing,storing and consumption of beverages.