Continuous step-wise temperature extraction improves the flavanol content of tea beverages

Tea is the second most consumed beverage worldwide and its health benefits have been extensively studied because of its rich flavanol content. This study aims to evaluate the efficacy of a novel continuous step-wise temperature extraction process in maximising antioxidant activity, total phenolic content and flavanol concentration of different tea beverages.

Continuous step-wise temperature extraction produced the highest absolute antioxidant capacity, total phenolic content and concentration of major tea flavanols in Yuhua tea compared to the other tea types at all extraction points. Despite having the lowest baseline concentration of tea flavanols, Lapsang Souchong tea showed the greatest increase in catechin and epigallocatechin-3-gallate levels with the continuous step-down temperature process, by over 500% and 300%, respectively. In addition, Moonlight White tea showed the greatest percentage change in total antioxidant capacity and phenolic content at the end of the process compared to the baseline. Furthermore, the continuous step-wise temperature extraction showed a moderate increase in caffeine concentration in all the tea samples.

Our findings revealed a beneficial impact of continuous step-wise temperature extraction on the antioxidant capacity, phenolic content and flavanol profile in different types of tea, which may be valuable in the production of added-value tea beverages. © 2024 Society of Chemical Industry.