单宁酶降低速溶绿茶中酯型儿茶素含量的研究

摘要

Esterified catechins are the major components resulting in bitterness and astringency in instant tea for the taste of additive applied products. Hence,more attention should be paid to the application of tannase in processing of instant tea for it degraded esterified catechins in tea. In this paper,the effects of tannase had been investigated on degrading esterified catechins for instant green tea solution at different concentrations,degradation values of EGCG for per unit tannase (mg)and the application of tannase in processing of instant green tea. The results showed that degradation values of EGCG for per unit tannase (mg)achieved 6. 70 mg·mg-1 at diopter of instant green tea solution 2. 35. The 3‰ addition of tea materials for tannase was suitable in applying to extracted and separated tea solution to obtain the instant tea powder with mellow taste. Comparing with only by extraction in hot water,applying tannase did not change the instant green tea significantly in the contents of tea polyphenols and catechins .%酯型儿茶素是速溶茶苦涩味的主体成分，其存在导致所应用产品口感苦涩，难以满足市场消费者的口感需求。单宁酶可降解茶叶中的酯型儿茶素组分，其在速溶茶加工中的应用值得关注。通过单宁酶对不同浓度速溶绿茶溶液的酯型儿茶素降解效果、单位单宁酶的 EGCG 降解量以及在速溶绿茶加工中的应用，结果表明，速溶绿茶溶液折光度为2．35时，单宁酶酯型儿茶素降解效果最好，单位单宁酶 EGCG 降解量可达6．70 mg·mg－1。应用于速溶绿茶加工时，单宁酶添加量以原料的3‰为宜，先提取分离后酶解，可获得口感醇和的速溶茶粉，茶多酚及儿茶素含量相较于热水提取基本不变。