四种茶饮料中茶多酚、游离氨基酸及维生素C含量分析及稳定性评价

本文检测了四种代表性市售茶饮料中的茶多酚、游离氨基酸和维生素C的含量,并研究茶饮料在室温未拆封持续贮藏5个月稳定性和拆封后室温下96 h内各指标变化。结果表明,除原叶绿茶中茶多酚略低于标准GB/T 21733-2008外,其他受试茶饮料各品质成分均符合相关标准,同时在室温未拆封存储条件下,各种茶饮料随储存时间的延长,茶多酚、游离氨基酸和维生素C含量明显下降;其中各样品中茶多酚在存储第3个月(即9月份)含量下降最明显,维生素C含量在存储第1~3个月(即7~9月份)下降较快,存储5个月后,只有调味绿茶中有维生素C检出,而调味红茶、原叶绿茶及原液红茶均未有维生素C检出。茶饮料开封后96 h内茶多酚、游离氨基酸和维生素C含量均明显下降,红茶饮料中维生素C在开封后72 h时只有微量检出,96 h后未有检出。以上结果表明茶饮料不宜长期室温存放,开封后不宜长时间放置。对茶饮料中主要品质成分茶多酚、游离氨基酸和维生素C含量及稳定性进行分析,能够为茶饮料生产、存储及消费提供参考。

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.