四川黑茶渥堆中品质成分的主成分及聚类分析

Principal component and cluster analysis of the quality ingredients of Sichuan dark tea during post-fermentation

以四川黑茶渥堆茶样为原料,采用主成分分析及聚类分析方法探讨四川黑茶渥堆过程中品质成分的变化规律。结果表明,主成分分析方法所提取的前2个主成分可以概括84.977%的品质成分信息,其中第1主成分以咖啡碱、水溶性果胶含量影响为主,第2主成分以茶黄素、茶褐素和氨基酸含量影响为主。系统聚类将渥堆进程分为3个时期,其中刚扎堆时为时期Ⅰ,扎堆后至一翻为时期Ⅱ,一翻后至出堆时为时期Ⅲ。实则,一翻后四川黑茶品质成分的转化已基本完成,水溶性果胶、咖啡碱、茶黄素、茶褐素和氨基酸为四川黑茶渥堆中影响品质形成的关键成分。

The method of principal component and cluster analysis were combined to investigate the variation characteristics of Sichuan dark tea quality ingredients during post-fermentation.The results showed that the first two principal components accounted for 84.977% of the total variation.The first principal component was mainly affected by the levels of caffeine and water soluble pectin ,the second principal component was mainly affected by the levels of theaflavin,theabrownin and amino acid.The period of post-fermentation was classified into 3 stages by hierarchical clustering：stage Ⅰ was the beginning of post fermentation（0d） ;stage Ⅱ was from the 3rd day to the 7th day; and stage Ⅲ was from the 9th day to the end of post-fermentation. It was demonstrated that the transformation of the quality ingredients of Sichuan dark tea had been almost completed after the 1stturning and mixing（Fandui） operation. Water soluble pectin, caffeine, theaflavin, theabrownin and amino acid were the key ingredients affecting the quality formation of Sichuan dark tea.