2025 Volume 58 Issue 1 Pages 16-22
This study determined the effect of extraction time on some functional constituents of three brands of Earl Grey tea, such as genuine Japanese black tea called wakocha (Aun), domestic tea (Nitto), and black tea produced in England (Twinings). An orthodox method for making tea used here was as follows: 3 g tea leaves were placed in 250 mL just-boiled water for 3 min extraction time. In the present study, the levels of theaflavin and caffeine, and superoxide dismutase (SOD) activity in the tea samples were determined for 3-, 5-, 7-, 10- and 15-min extraction times. The efficiency of extraction of constituents from tea leaves reached the maximum value in 10 min. Theaflavin content in the 10-min extract was 1.5-times that in the 3-min extract. Similar results were obtained for caffeine content and SOD activity. For maintaining functional properties and relatively low astringency of the 10-min extracted Earl Grey tea, the usage of cow's or soy milk is proposed.
