利用单宁酶改善绿茶滋味品质的研究

Improvement Effects of Tannase on Flavor Quality of Green Tea

为了利用外源单宁酶改善夏茶滋味品质成分和组成,实验设计了在传统绿茶加工工艺的揉捻工序中,添加不同浓度的外源单宁酶,比较不同处理的成品茶在多酚类物质、儿茶素和氨基酸含量方面的差异,分析单宁酶提高夏季绿茶品质的效果。结果表明:单宁酶处理和对照相比,茶叶中茶多酚总量无显著性差异,但儿茶素的组成变化很大,其中表没食子儿茶素没食子酸酯(EGCG)明显下降;氨基酸总量有所增加,其中谷氨酸等一些低阈值氨基酸含量增加更为明显。这些成分变化对改善夏季绿茶滋味有积极意义,在夏茶加工中添加外源单宁酶可以在一定程度上降低苦涩味,从而提高茶汤的鲜醇度。

In this study, in order to explore the possibility of improving green tea quality with exotic tannase, different concentrations of tannase were mixed with tea leaves in the rolling period of the traditional tea process, and biochemical compositions were analysed in samples of made tea. The results showed that the total content of polyphenols has no substantial difference between the control and the treated samples, while the content of amino acid rises slightly in treated sample compared with that in the control sample. A prominent finding was obtained that tannase application substantially decreases the proportion of catechin-gallate including epigallocatechin gallate （EGCG） in total catechins but increases some taste-sensitive amino accids such as Glu. These changes have positive effects on improving tea quality, which implies that the harshness of green tea could be reduced and mellowness could be enhanced by adding some quantity of tannase in tea processing from fresh leaves plucked in summer season.