Differential Analysis of Quality Components of Flat Green Tea from Different Producing Areas

In order to systematically and comprehensively understand the quality characteristics of flat green tea,the sensory quality,color difference,and content differences of tea polyphenols,free amino acids,caffeine and water extracts from five different areas(Dawu county,Hubei province,Panan county,Zhejiang province,Shexian county,Anhui province,Meitan county,Guizhou province,Emeishan city,Sichuan province)were analyzed. Results showed that the L1 value(brightness)and b1 value(yellowness and blueness)of dry Longjing tea were 38.20 and 19.35,respectively,both significantly(P<0.05)higher than that of the other four types of flat green tea. The L3 value(brightness)of Dafang tea soup was the highest. The total amount of water extracted of Dafang tea and Meitan Cuiya tea were over 48.00%,significantly(P<0.05)higher than that of Xiaogan Longjian tea,Longjing tea and Zhuyeqing tea. The contents of free amino acid,caffeine,catechin,epicatechin gallate and catechin gallate were all the highest in Meitan Cuiya. The content of epigallocatechin gallate was the highest in Xiaogan Longjian tea. The partial least square discriminant analysis model based on the relative content of each quality component successfully distinguished the flat green tea samples from five producing areas. The variable important for the projection value(VIP>1)was used to screen 11 key quality components as quality indexes to distinguish five flat green teas,which were E1(dry tea),L1(dry tea),b1(dry tea),epicatechin gallate,gallocatechin gallate,caffeine,free amino acid,a3(tea soup),b3(tea soup),L3(tea soup)and E3(tea soup). This study would provide a scientific reference for the processing technology and quality improvement of flat green tea.