Influence of shooting period and extraction conditions on bioactive compounds in Turkish green tea

Abstract The aim of this study was to investigate the influence of different extraction temperatures (75, 85 and 95 °C) and times (3, 5, 10, 15 and 20 min) on bioactive compounds in Turkish green tea produced and classified as Turkuaz, Kardelen and Antikyeşil by ÇAYKUR (the Turkish Tea Board) over three shooting periods. Green tea extracts were subjected to analyses of extraction yield, antioxidant capacity, total phenolic and flavonoid contents, and the phenolic and flavonoid composition. Total phenolic and flavonoid contents and the antioxidant capacity of samples increased when extraction temperatures and times were increased. Extraction yield, total phenolics, total flavonoids and the antioxidant capacity of the green teas were found in the range of 21.52-37.40 g 100 g-1, 68.13-131.31 mg GAE g-1 dw, 17.97-32.04 mg CE g-1 dw and 0.48-1.16 mg dw mg-1 DPPH, respectively. The average amounts of individual catechins, i.e. catechin, epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate, gallocatechin gallate, gallocatechin and catechin gallate were found in the range of 8.91-17.09, 4.29-9.55, 28.03-59.42, 8.02-14.61, 38.05-69.66, 2.53-18.53, 2.30-12.97 and 0.04-1.78 mg g-1 dw, respectively.