Comprehensive Quality Assessment of Wuning Wild Tea: Multivariate Statistical Analysis, TOPSIS-GRA Evaluation, and Interaction between Theaflavin-3,3′-Digallate and Pepsin

Wild tea is highly valued for its perceived superior quality, yet scientific validation remains limited. Therefore, this study comprehensively evaluated the quality of Wuning wild tea. Compared to cultivated tea, Wuning wild tea exhibits superior essential chemical constituents, including tea polyphenols and free amino acids, and its functional component composition and quality characteristics are better. Wuning wild black tea (WBT) was shown to possess the highest quality among the 11 teas evaluated through multivariate statistical analysis and the technique for ordering preferences for similarity to ideal solutions-gray relational analysis (TOPSIS-GRA) coupled model, and to possess strong antioxidant activity. Mechanistic studies revealed that the interaction between theaflavin-3,3′-digallate (TFDG) and pepsin (PEP) follows a static quenching mechanism. UV–vis spectroscopy analysis showed that TFDG reduces the hydrophobicity of tyrosine and tryptophan residues in PEP. These results provide a scientific basis for the superior quality of wild tea.