不同湿坯闷黄方式对黄茶γ-氨基丁酸含量及品质的影响

Effect of Different Wet Yellowing Methods on the GABA Content and Quality of Yellow Tea

为探究湿坯闷黄方式对黄茶γ-氨基丁酸含量及品质的影响,试验以鸠坑茶树品种一芽一二叶鲜叶为原料,重点分析在不同茶坯含水率、闷黄方式和闷黄时间等条件下,黄茶γ-氨基丁酸和主要品质成分含量变化以及感官品质差异。结果表明:1)黄茶品质与闷黄前茶坯含水率有关,茶坯含水率为42.44%时,黄茶综合品质最佳,得分为88.13分,闷黄前茶坯含水率与黄茶中游离氨基酸相关性最强,相关系数为0.825;2)黄茶品质与闷黄方式和闷黄时间有关,黄茶品质高低顺序为机械闷黄>烘笼闷黄>自然闷黄,机械闷黄6 h的黄茶品质最好,综合得分为89.95分;烘笼闷黄的时间以4 h最佳,自然闷黄以8 h为宜;3)γ-氨基丁酸与咖啡碱具有较强的相关性,相关系数为-0.860;茶坯含水率为44.75%时γ-氨基丁酸含量较高,为0.081%;不同闷黄方式的黄茶γ-氨基丁酸含量顺序为烘笼闷黄>机械闷黄>自然闷黄,前两种方式均在闷黄时间为4 h时含量最高,分别为0.1%和0.092%。该试验为黄茶湿坯闷黄工艺的完善提供理论依据和技术参考。

In order to explore the effect of wet yellowing methods on the GABA content and quality of yellow tea,in this study,the fresh leaves of one bud and two leaves of the Jiukeng tea variety were used as raw materials,and the focus was on the changes in the content ofγ-aminobutyric acid and main quality components and sensory quality differences of yellow tea under different conditions such as the moisture content of tea,the yellowing method and the yellowing time.The results showed that:1)The quality of yellow tea was related to the moisture content of tea before heaping for yellowing.When the moisture content of tea was 42.44%,the overall quality of yellow tea was the best,with a score of 88.13 points.The moisture content of tea before heaping for yellowing had the strongest correlation with the free amino acids in the yellow tea,and the correlation coefficient was 0.825.2)The quality of yellow tea was related to the yellowing method and the yellowing time.The order of yellow tea quality was mechanical yellowing>drying cage yellowing>natural yellowing,and the quality of the yellow tea with mechanical yellowing for 6 hours was the best,with a comprehensive score of 89.95 points;The drying cage yellowing was the best for 4 h,and the natural yellowing was the best for 8 h.3)GABA and caffeine had a strong correlation,with a correlation coefficient of-0.860;When the moisture content of tea was 44.75%,the content ofγ-aminobutyric acid was higher,which was 0.081%;The order of the content ofγ-aminobutyric acid in yellow tea with different yellowing methods was drying cage yellowing>mechanical yellowing>natural yellowing,the first two methods had the highest content of 0.1%and 0.092%,respectively,when the yellowing time was 4 h.This test provided a theoretical basis and technical reference for the perfection of the wet yellowing process of the yellow tea.