Ultrasonic Assisted Extraction and Antioxidant Activity of Tea Polysaccharides from Pu'er Tea Residue

In order to solve the environmental problems caused by the Pu'er Tea tea residue, this research explored the optimization technology of tea polysaccharide ultrasonic-assisted extraction process in Pu'er Tea tea residue, and researched about oxidation resistance of tea polysaccharide that was extracted by optimum process conditions. Response surface test in the research was on the basis of single factor experiment, then the 4 factors and 3 levels response surface methods were designed for the ultrasonic assisted extraction process of tea polysaccharides. The results showed that the best combination of experimental factors of tea polysaccharide ultrasonic-assisted extraction process in Pu'er tea-leaves were extraction temperature 100℃, extraction time 120 min, ratio of solid to liquid 1:30, ultrasonic power 420 W. Under this condition, tea polysaccharide extraction yield was 2.29%. The tea polysaccharides obtained by this process have strong scavenging capacity for hydroxyl radicals and superoxide free radicals:when the concentration of tea polysaccharide was 3.2 mg/mL, the scavenging rate of tea polysaccharide on hydroxyl radical got the highest, which was 60.37%;when the concentration of tea polysaccharide was 2.4 mg/mL, the scavenging rate of tea polysaccharide on hydroxyl radical got the highest, which was 53.91%.