Analysis of Variations in Contents of Extractable Components and Taste Quality of Pu-erh Raw Tea with Different Brewing Cycles

The contents of extractable components and taste characteristics of Pu-erh raw tea infusions obtained at different brewing times were analyzed by employing ultra performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) combined with sensory evaluatio in this study. The results showed that a total of 138 extractable components were identified, the predominant ones being amino acids, catechins and their derivatives, phenolic acids and their derivatives, flavonoids and alkaloids. These substances made a significant contribution to the umami, bitterness and astringency of tea influsions. The sensory score for taste of Pu-erh raw tea infusion was positively correlated with the degree of bitterness, astringency and thickness; there was also a positive correlation between the total amount of extractable components and the sensory score for taste for tea infusion obtained at each brewing cycle. The total amount of extractable components and the taste score reached their maximum values at the second brewing cycle, and then the total amount of extractable components decreased and the taste became increasingly plainer and thinner with increasing number of brewing cycles. These findings help to reveal the durability of Yunnan Pu-erh raw tea and the taste change of tea infusion during the brewing process.