. Preparation of green tea extract (GTE)
GTE was prepared according to the method of Nirmal and Benjakul
(2011). Green tea powder was treated with chloroform using a
powder/solvent ratio of 1:20 (w/v) to remove chlorophyll. The
mixture was stirred for 30 min, followed by filtration using a
Whatman filter paper No.1 (Schleicher & Schuell, Maidstone,
England). To prepare GTE, the de-chlorophyllised green tea powder
(2 g) was mixed with 80 mL of 80% ethanol at 40 °C for 2 h with
continuous stirring. The extract was filtered through a Whatman filter
paper No.1. The filtrate was concentrated by a rotary evaporator
(EYELA N-100, Tokyo, Japan). The concentrated sample was dried in
hot air oven at 60 °C for 12 h. GTE powder was kept in a polyethylene
bag and placed in a dessicator in the dark at 4 °C until use.