EXTRACTS OF GREEN TEA COMPRISING LOW CAFFEINE HAVING ANTIOXIDANT ACTIVITY USING ULTRASONIC WAVES AND PREPARING METHOD THEREOF

摘要

The present invention relates to a method for preparing a green tea extract having excellent antioxidant activity while lowering the caffeine content by using ultrasonic extraction, so as to prevent the excessive intake of caffeine and utilize positive effects of caffeine. More specifically, a green tea extract containing a low content of caffeine and having antioxidant activity, of which the antioxidant activity is 80-92% and the caffeine content is 13-17 mg/g, can be provided by immersing green tea in 15-25 volume% of an aqueous ethanol solution, followed by ultrasonic irradiation at 20-30C for 20-30 minutes. The green tea extract according to the present invention contains a low content of caffeine and has high antioxidant activity, and thus can be used as a food additive or a functional health food.