Research of ultrasound-assisted extraction of Xinyang Maojian tea pigment and its antioxidant activity

Objective:To optimize the extraction process for Xinyang Maojian tea pigment and explore its antioxidant activity. Methods:Effect of four factors on the extraction,including ratio of solid to liquid,ultrasonic temperature,ultrasonic time and extraction times were studied by single factor and the optimum extraction conditions were then determined through the orthogonal experiment. 1, 1- diphenyl- 2- picrylhydrazyl( DPPH) free radical scavenging assay,superoxide and hydroxyl radical scavenging assay were used to evaluate the antioxidant activity of the pigment. Results:The order of factors to affect flavonoids extraction was ratio of material/solution>extraction times>ultrasonic temperature>ultrasonic time. The optimal extraction conditions were material/solvent ratio 1∶30,extraction temperature of 80℃ and extraction time of 120 min,for three times. Under such conditions,the yield of the melanin reached 33.1%. The Xinyang Maojian tea melanin exhibited a moderate antioxidant activity. It was clearly demonstrated that free radical scavenging increases with increasing melanin concentration.The melanin had strong scavenging activity on hydroxyl radical. Conclusion:The extraction rate of Xinyang Maojian tea pigment was improved by orthogonal experiment. The pigment had antioxygenation effect obviously,and it could be further developed and utilized as a natural antioxidant.