In order to analyze the relationship of the sixteen tea samples, PCA
was carried out based on the Trolox equivalent concentrations of the
ten bioactive components. In Fig. 5A, the PCA score plot showed
that all the samples could be divided into three groups, i.e. oolong
tea (S7–S12), green tea (S1–S6) and white tea (S13–S16). Hierarchical
clustering analysis of the sixteen tested samples was also
performed based on the Trolox equivalent concentrations of the ten
bioactive components. The results presented in Fig. 5B showed clearly
that sixteen tested samples were appropriately divided into two main
clusters. The samples of oolong tea (S7–S12) were grouped as one
distinct cluster (Cluster I). The samples of green tea and white tea