基于主成分和聚类分析研究茯砖茶加工过程品质变化

研究了茯砖茶加工过程中10个时间阶段的样品,分析测定了18个品质成分,对所得结果进行主成分分析和聚类分析,构建样品与品质成分之间的关系。结果表明:EGCG、GCG、ECG、茶多酚、可溶性糖、没食子酸和水浸出物是茯砖茶加工过程中的主要变化物质。提取的三个主成分贡献率分别为56.45%、26.29%和8.46%。结合聚类分析可得茯砖茶加工过程可分为4个阶段:第一阶段为毛茶期,包括毛茶和发花第0 d;第二阶段为发花前期,包括渥堆、发花第3 d和发花第6 d;第三阶段为发花后期,包括发花第9 d、发花第12 d、发花第15 d;第四阶段为茯砖茶干燥期,包括发花第18 d、发花第22 d。本研究为茯砖茶加工过程中品质成分的变化建立了评价体系,确定了加工过程各时间段的分界限。 

Quality changes of Fuzhuan Tea during processing period based on principal component and cluster analysis

Ten time periods samples from processing process of Fuzhuan Tea were collected, and 18 quality component were measured.Principal component analysis and cluster analysis were used to investigate the quality component, the relationship between the sample and the quality component were constructed. The results indicated that major changed components in the processing of Fuzhuan Tea was EGCG, GCG, ECG, tea polyphenols, soluble sugars, gallic acid and water extracts. The contribution ratios of the three principal components were 56.45%, 26.29% and 8.46%.It could be concluded through cluster analysis that processing process of Fuzhuan Tea was divided into four stages. The first stage was the Maocha period, including the Maocha and the zeroth day of fungus growing.The second stage was the early stage of fungus growing, including the pilefermentation, the third and sixth day of fungus growing.The third stage was the late stage of fungus growing, including the 9th day, the 12 th day and the 15 th day of fungus growing.The fourth stage was the drying period of Fuzhuan tea, including the 18 th day, and the 22 th day of fungus growing.This study established a evaluation system to change the quality of the process during the processing of Fuzhuan tea, and determined the Fuzhuan tea processing time of the dividing line.