Studies on Antioxidant Activities of Papaya (Carica papaya) and Pineapple (Ananas cosmosus) Fruits Using Ferric Reducing Antioxidant Power and Rancimat Methods

Most health-benefits of fruits and vegetables have often been attributed to their antioxidant contents. This paper reports attempts made to look into the antioxidant activities of papaya (Carica papaya) and pineapple (Ananas cosmosus) fruits purchased from fruit shops in Bahir Dar City, North-West Ethiopia, using ferric reducing antioxidant potential (FRAP) and Rancimat methods. The antioxidant activity of the fruits found in the FRAP assay is expressed in terms of μg of ascorbic acid (AA) equivalent per gram of edible flesh part of ripen fresh fruit while that found in the Rancimat method is expressed in terms of protection factor. The FRAP value of papaya fruit (13.6 μg AA/g sample) was found to be higher than that of pineapple fruit (8.6 μg/g AA /g sample). Similarly the protection factor of papaya (1.103) was found to be greater than that of pineapple fruit (1.036). In both the assays employed, it is seen that both papaya and pineapple fruits do exhibit antioxidant properties with the former showing greater reducing power. Keywords: Antioxidants, Antioxidant capacity, Oxidative stress, Ferric-ion reducing antioxidant power, Rancimat metho