Effect of tannase on sediment formation in green tea infusion

Reducing sediment is important for the utilization and production of green tea infusion and concentrate. The effect of tannase on sediment formation in green tea infusion and concentrate was investigated. The results showed that the amount of sediment of green tea infusion significantly decreased after tannase treatment, which was due to the decrease in the concentration of gallated catechins. Significant positive correlations between the sediment amount and the gallated catechin (r = 0.980, p < 0.01) concentration were found. The formation of sediment in green tea infusion was significantly influenced by the tannase concentration and hydrolysis time. 0.5 mg/mL tannase concentration, 120 min hydrolysis time, and 35 °C hydrolysis temperature were found to be the optimized hydrolysis parameters for reducing the sediment. Tannase treatment not only lowered the amount of sediment of green tea concentrate (74.63%), but it also improved the taste quality of green tea concentrate after storage. These results could be used to improve the quality and utilization of green tea infusion and concentrate.