Differences in the analysis of the quality indexes and characteristic amino acids of the different grades of Wuyi Shuixian (Camellia sinensis) tea

Abstract

The objective evaluation of the quality of the Wuyi rock tea remains challenging. In this study, 649 samples comprising four grades of Wuyi Shuixian tea from the “Spring Tea Competition, 2019” were collected to determine their quality indexes. The results showed that the higher the grade of the Wuyi Shuixian tea, the higher the individual scores from the sensory evaluation. The water extracts, catechin, aspartic acid, and tyrosine were significantly different among the different tea grades. Restricted principal coordinate analysis showed that different grades of Wuyi Shuixian tea could be effectively differentiated using the tea quality indexes and 15 free amino acids. The total quality score of the sensory evaluation was significantly negatively correlated with the hydrophobic amino acids, bitter amino acids, and ECG, and was significantly positively correlated with GCG. These results suggest that the high content of the multicomponents is the material basis of the high quality of the tea. The hydrophobic amino acids, bitter amino acids, ECG, and GCG can be used to evaluate the differences in grades of the Wuyi Shuixian tea. The results of this study are expected to provide a theoretical basis for objectively evaluating the differences in the qualities of the Wuyi Shuixian tea.

Keywords:
Wuyi Shuixian tea; tea grades; sensory evaluation; characteristic amino acid; quality index