Abstract: The simultaneous microwave extraction conditions of total phenolics and flavonoids from pineapple peels grown in Hainan,Guangdong and Guangxi areas were optimized via L9(33) orthogonal test,and their antioxidant activities were determined. The results showed that the optimal extraction conditions of both total phenolics and flavonoids are as follows:extraction time 160 s,microwave power 450 W,and ratio of raw material to 75% ethanol as extraction solvent 1:40. The contents of total phenolics in pineapple peels from the three areas are 979.0,898.1 and 839.6 mg/100 g,respectively,and those of total flavonoids are 882.7,642.4 and 588.7 mg/10 g,respectively. All the extracts have better antioxidant activities of scavenging 2,2-diphenyl-1-picrylhydrazyl(DPPH) free radical than hydroxyl radical,with the scavenging rates of 87.6%,79.8% and 81.6%.

Key words: pineapple peel, total phenolics, total flavonoids, antioxidant activity