Ultrasonic Extraction and Antioxidant Activity of Polysaccharide from Dixu Tea

In order to comprehensively utilize Dixu tea resources,ultrasonic assisted extraction technology and in vitro antioxidant activity of Dixu tea polysaccharide were studied. The effects of particle size,ultrasonic time,solid-liquid ratio,extraction temperature and ultrasonic power on the yield of polysaccharide were investigated. The optimal extraction process was determined by orthogonal test and its antioxidant activity was investigated.The results showed that the optimum extraction process was as follows:Particle size 40 mesh,liquid-material ratio 1:40 g/mL,ultrasonic time 110 min,ultrasonic temperature 60 ℃,ultrasonic power 750 W,under these conditions,the average extraction yield ofpolysaccharide was 11.28%±0.49%. The results of antioxidant activity in vitro indicated that the polysaccharide had a certain scavenging ability to the superoxide free radicals,hydroxyl radical,DPPH and ABTS free radicals,the rates were respectively 66.55%±2.67%,85.17%±1.70%,66.48%±2.99%,82.37%±1.00% at 2.0 mg/mL.The polysaccharide obtained under optimum extraction conditions exhibited strong antioxidant activities,which could be effectively used in making natural antioxidants.