茶树单宁酶CsTA的理化性质及其在绿茶饮料中的应用  

Physicochemical Properties of Tannase in Tea Plants(Camellia sinensis) and Its Application on Green Tea Beverages

作　　者：陈一凡 阚新意 蒋晓岚[1] 高丽萍[2] 夏涛[1] CHEN Yifan;KAN Xinyi;JIANG Xiaolan;GAO Liping;XIA Tao(State Key Laboratory of Tea Plant Biology and Utilization,Anhui Agricultural University,Hefei 230036,China;School of Life Science,Anhui Agricultural University,Hefei 230036,China)

机构地区：[1]安徽农业大学茶树生物学与资源利用国家重点实验室,安徽合肥230036 [2]安徽农业大学生命科学学院,安徽合肥230036

出　　处：《茶叶科学》2023年第1期124-134,共11页Journal of Tea Science

基　　金：国家自然科学基金(31870676);国家自然科学基金联合基金(U21A20232);安徽省教育厅科学研究项目(YJS20210211)。

摘　　要：茶叶中的酯型儿茶素对于绿茶滋味有着重要的影响,但是夏秋季节茶树中积累过多的酯型儿茶素会降低茶叶感官品质。前期发现的茶树单宁酶CsTA具有水解酯型儿茶素的功能,但其理化性质以及能否在绿茶饮料加工中发挥一定作用尚不清楚。在前期试验结果的基础上利用液相色谱技术对CsTA进行进一步探究。结果表明,单宁酶CsTA的最适反应温度为45℃、热稳定范围在60℃以下、最适反应pH为7.0,Mg^(2+)对单宁酶CsTA活性有明显的激活作用,Cu2+可使其完全失活,Mn^(2+)、Zn^(2+)、Al^(3+)、Fe^(3+)、Fe^(2+)、Li^(+)对单宁酶CsTA活性具有一定抑制作用,CsTA在冷冻干燥后有很好的贮存稳定性。将茶树单宁酶CsTA应用于绿茶茶汤后发现,当茶树单宁酶CsTA添加量为11μg、料液比为1∶100、作用时间20 min、温度为35℃时对绿茶茶汤中酯型儿茶素的降解效果最好。本研究为今后利用CsTA在绿茶饮料生产中降低苦涩味,提升品质提供理论参考。Galloylated catechins have an important impact on the taste of green tea, but excessive accumulation of galloylated catechins in tea plants in summer and autumn will reduce the sensory quality. A native Camellia sinensis tannase(CsTA) discovered in the previous study has the function of hydrolyzing galloylated catechins. But its physicochemical properties and whether it can play a role in the processing of green tea beverages are not clear. In this article, the CsTA was further studied on the basis of previous experimental results. The results show that the optimal temperature of the enzyme was 45 ℃, the thermal stability range was below 60 ℃, the optimal reaction pH was 7.0. Mg^(2+) had a significant activation effect on CsTA. Cu^(2+) could completely inactivate CsTA activity. Mn^(2+),Zn^(2+), Al^(3+), Fe^(3+), Fe^(2+) and Li^(+) had a certain inhibitory effect, and CsTA had a good storage stability after freeze-drying. After applying CsTA to green tea infusion, it was found that the best degradation effect of ester catechins was obtained when the added amount was 11 μg, the ratio of material to liquid was 1∶100, the reaction time was 20 min, and the temperature was 35 ℃. This study would provide a theoretical reference for using CsTA to reduce the bitterness and astringency and improve the quality of green tea processing in the future.

关 键 词：酯型儿茶素 茶树单宁酶 理化性质 绿茶饮料加工 

分 类 号：S571.1[农业科学—茶叶生产加工] TS272.5[农业科学—作物学]