客家炒青绿茶加工过程中品质成分的动态变化

为了研究客家炒青绿茶加工过程中的主要品质成分动态变化规律,以广东客家小叶群体种-仙湖茶为原料,按摊青、杀青、揉捻、炒青、辉干等工艺制作炒青绿茶,对加工过程中的主要内含物成分及香气组成进行测定分析。结果显示,随着加工的进程,茶叶在制品含水率呈下降趋势,以“炒青”工序最为显著,含水率降至4.74%,降幅达91.63%;在“炒青”工序,茶叶生化成分含量变化最大：可溶性糖含量达到最大值5.71%,水浸出物含量达到最小值35.85%,氨基酸含量达到最小值2.71%。加工过程中,水浸出物、氨基酸、茶多酚及咖啡碱呈下降趋势,儿茶素总量及酯型儿茶素含量的变化趋势与茶多酚一致。香气组分以醇类物质为主,其中香叶醇、芳樟醇、二十八烷醇及叶绿醇等化合物在炒青绿茶不同阶段加工过程中占比较高且变化幅度较大。该研究揭示了客家炒青绿茶加工过程中的主要风味物质变化过程,可为优化客家炒青绿茶加工工艺与品质良好风味的形成提供数据参考。

Dynamic Changes of Quality Components in Hakka Roasted Green Tea during Processing

In order to study the dynamic changes of the main quality components in the processing of Hakka roasted green tea, Xianhu tea, the Hakka small-leaf group of Guangdong Province, was used as the raw material to make roasted green tea through spreading, killing, twisting, stir-frying and drying. The main contents and aroma components during the processing were determined and analyzed. The results showed that the moisture content of tea decreased as the process proceeded, with the decrease being the most significant at the "stir-frying" step (the moisture content decreased to 4.74%, with a reduction of 91.63%). During the "stir-frying" step, the contents of the biochemical components in tea changed the most: the content of soluble sugar reached the maximum (5.71%), the content of water extract reached the minimum (35.85%), the amino acid content reached the minimum value (2.71%). During the process, the water extract, amino acid, tea polyphenol and caffeine contents showed a downward trend, and the changing trends of the total catechin content and ester catechin content were in accordance with that of the tea polyphenols. The aroma components were mainly alcohols, among which, the compounds such as geraniol, linalool, octadecanol and chlorophenol accounted for higher proportions and underwent larger changes at different stages of roasted green tea processing. This study reveals the changes of the main flavor substances during the processing of Hakka roasted green tea, which can provide data reference for optimizing the process of roasted green tea and the formation of good quality flavor.