Production of low-tannin tea through D-optimal design optimization of the preparation conditions and the catalytic action of new tannase.

Many tannase-based industrial applications are currently being developed to successfully break down tannins in teas and juices. However, so far, no study has demonstrated the potential application of tannase to reduce tannin levels in tea. The D-optimal design was utilized to predict the optimal conditions for maximizing anthocyanins and decreasing tannin content in tea. Then, the effects of tannase were evaluated by examining the physicochemical parameters and α-amylase inhibitory action of untreated and treated tea, as well as quantifying catechin content changes using HPLC. Following treatment with tannase, the esterified catechins decreased by 8.91%, while the non-esterified catechins increased by 19.76%. Additionally, tannase significantly raised the total phenolic compounds by 8.6%. In contrast, the α-amylase inhibiting activity of tea decreased by ≈28%. As a novel member of the tea family, tannase offers an excellent means of conditionally producing low-astringency tea.