Classification of Pu-erh ripened teas and their differences in chemical constituents and antioxidant capacity
Binxing Zhou, Bingsong Ma, Cunqiang Ma, Chengcheng Xu, Jiacai Wang, Ziyu Wang, Dingfang Yin, Tao Xia
Abstract
For the scientific classification of Pu-erh ripened teas (PRTs), phytochemical compositions including 14 polyphenolic compounds, 2 purine alkaloids and 18 free amino acids in 24 PRTs were determined by HPLC, respectively. The in vitro antioxidant activities were evaluated by 5 various assays. PCA explaining 38.7% of total variance, HCA and OPLS-DA (R2Y = 0.887, Q2 = 0.873, respectively) could classify PRTs into Puer and Banna groups by production place basically, which caused significant (P < 0.05), highly significant (P < 0.01) or extremely significant (P < 0.001) differences of 29 chemical components. The 19 relevant components used for the identification of storage location through OPLS-DA (R2Y = 0.625, Q2 = 0.601, respectively) were selected. PRTs of various origins, such as production place and storage location, demonstrated significant (P < 0.05) differences in antioxidant activities. Several polyphenolic compounds like (−)-epicatechin, (−)-gallocatechin, rutin and kaempferol contributed to the antioxidant activities. This study helps to understand chemical profile and antioxidant activities of PRTs.