Enzymatic treatment in black tea manufacturing processing: Impact on bioactive compounds, quality, and bioactivities of black tea

This study investigated the changes of main quality components and the effect of bioactivities of black tea during a manufacturing process that adds to enzymatic treatment. It used black tea harvests in summer and autumn for manufacturing and analyzed the number of main quality components and bioactivities of the black tea produced by treating cellulase during rolling and polyphenol oxidase (PPO) and peroxidase (POD) during fermentation. The results found that the contents of total catechins (TC), total polyphenols (TP), reducing sugars (ReS), and individual catechins in the tea infusions of summer and autumn black tea that were obtained during enzymatic treatments decreased significantly (p < 0.05). However, the content of free amino acid (FAA), the tea quality parameter such as the total liquor color (TLC), the briskness index (BI), and the tea pigments including total theaflavin (TF), thearubigens (TR), TRSI, and TRSII all increased significantly (p < 0.05). Moreover, the biological activity enhanced black tea's antioxidant and metabolic capacity with enzymatic treatments were proved by in vitro experiments. The results of this study contribute to gaining further knowledge on how black tea's quality and potential health benefits are maximized by using exogenous enzyme addition methods in the manufacturing process preparation.