Analysis and Evaluation of Taste Quality of Pu’an Black Tea Based on Multivariate Statistics

For comprehensive evaluation of the taste quality of Pu’an black tea, the taste characteristics of black teas made from Camellia tetracocca Zhang (SQ) and Yunnan large-leaf cultivars (YD) in Pu’an county, Guizhou province were evaluated by sensory evaluation, quantitative taste assessment and chemical composition analysis combined with taste activity value (TAV) analysis and multivariate statistics, and taste contributors and differential taste compounds among different types of Pu’an black tea were identified. The results showed that Pu’an black tea had a sweet, mellow and strong taste. SQ had stronger sweetness and mellowness, while YD presented a more intense taste. SQ showed significantly lower contents of caffeine, theaflavins, thearubigins, and theabrownin but significantly higher soluble sugar contents compared with YD. The TAV of theanine and glutamic acid, two amino acids that contributed the most to the taste, were much greater than 1. Correlation analysis showed that cysteine was the major sweet amino acid. Tea polyphenols, caffeine, theaflavins, and histidine were the major sources of bitterness and astringency in tea soup. Orthogonal partial least squares-discriminant analysis (OPLS-DA) identified 11 differential taste components between SQ and YD, including leucine, serine, caffeine, threonine, isoleucine, lysine, arginine, valine, cysteine, glutamic acid and thearubigins. Principal component analysis (PCA) based on 26 taste components revealed that the mean value of comprehensive scores for taste quality of different types of Pu’an black tea decreased in the following order: SQ2 (1.15) > YD0 (0.23) > YD1 (−0.44) > YD2 (−0.83). It was found that Pu’an black tea produced from one bud and two tender leaves of C. tetracocca Zhang exhibited the best taste quality. This finding provides a reference for the development of Pu’an’s black tea industry.