Abstract
Total polyphenol content and antioxidant activities of non-edible parts (seed and peel) of eight tropical fruits were analyzed and compared with those of their edible parts. The antioxidant activity was evaluated based on the ability of the fruit extracts (seed, peel and pulp) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals, and the ferrous ion-chelating capacity. Total polyphenol content in seed, peel and pulp ranged from 0.2 to 153, 5.0 to 124, and 1.0 to 12 mg/g DW, respectively. Non-edible parts of the tropical fruits were found to have significant antioxidant activities. Among them, mango seed, mango peel, starfruit peel and avocado peel showed higher antioxidant potential by the DPPH and ABTS radical scavenging assays. The DPPH and ABTS radical scavenging abilities were highly correlated with total polyphenol content. Kiwano and papaya peels showed strong ferrous ion-chelating capacity, although they did not have high polyphenol content and DPPH and ABTS radical scavenging activities.
