Comparative Analysis on Quality of Sun-dried Tea from Main Tea Production Areas of Yunnan

Eighteen sun-dried tea samples were selected from six major tea-producing regions in Yunnan Province, namely Xishuangbanna, Pu'er, Lincang, Baoshan, Dehong and Yuxi to use for this study. In this study, these samples' biochemical components such as moisture, water leachate, caffeine, tea polyphenols and free amino acids were tested and their sensory evaluations were conducted. The quality differences of sun-dried tea from different regions in Yunnan Province were investigated by means of index correlation analysis, principal component analysis, cluster analysis and quality appellation analysis, and high-quality production regions were screened. The results showed that the quality indicators of different regional sun-dried tea had differences and there were some correlations among the quality indicators. Among them, the water leachate content showed correlation with the content of tea polyphenol and leaf base (P<0.05). Similarly, the content of amino acid and caffeine, aroma and taste showed a correlation (P<0.05). Besides, the average values of moisture, water leachate, caffeine, tea polyphenols and free amino acids of sun-dried tea from Yuxi region were 8.08%, 52.82%, 4.81% and 27.78%, and 4.64%, respectively, which were higher than those of other regions. The sun-dried tea from Xishuangbanna had the highest phenolamine ratio (8.94), and the overall quality of sun-dried tea samples from Yuxi and Xishuangbanna regions was better than other regions. Making a cross-analysis of the previous classification of suitable regions for tea cultivation in Yunnan Province and the results of this study on the comprehensive evaluation of the quality of sun-dried tea from different regions. It showed that Xishuangbanna not only has very suitable climate for tea cultivation, but also could product high quality sun-dried tea. The above results could indicate the differences in the quality of sun-dried tea from different regions in Yunnan. Moreover, it could provide references for the production of high quality pu-erh tea products in the future.