Abstract:

Polysaccharides in Ananas comosus (L.) Merr. (pineapple) peel, a byproduct from the extraction of pineapple juice, were extracted using hot water. On the basis of single factor experiments, three crucial extraction parameters such as material/ water ratio and extraction time and temperature were optimized for maximizing yield of polysaccharides from pineapple peel using a three-variable, five-level quadratic rotation combination experimental design. Subsequently, the in vitro antioxidant activities of the polysaccharides from pineapple peel were evaluated by superoxide anion radical, hydroxyl radical and ABTS radical scavenging assays. A maximum amount of 23.72 mg of polysaccharides was obtained from 1 g of pineapple peel by the optimal extraction for 5 h using 70 ℃ hot water at a material/water ratio of 1:25 (m/V). The polysaccharides from pineapple peel had a certain degree of antioxidant activities in vitro: scavenge hydroxyl radicals and ABTS radicals in a dose-dependant manner with the IC50s of 1.76 and 2.49 mg/ml, respectively.

Key words: pineapple peel, polysaccharide, antioxidation, rotation combination experimental design