Antioxidant Activity in Pulp and Peel of Three Mango Varieties

Abstract

The aim of the present study was to estimate the content of total polyphenols and flavonoids and to investigate in-vitro antioxidant potential of methanolic extracts of peel and pulp in three Indian mango varieties. Antioxidant activity was assessed using [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] ABTS+ assay, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay, ferric-reducing ability of plasma (FRAP) assay, and phosphomolybdate assay for Total Antioxidant Capacity (TAC). Total phenolic and flavonoid content was also determined, and expressed in gallic acid equivalent (GAE) and quercetin equivalent (QE), respectively. Results of this study indicated that methanolic extracts of mango peel had significantly higher antioxidant activity compared to that of pulp (29.69 and 3.12), irrespective of the method or variety used. Free radical scavenging and antioxidant activity may be attributed to presence of phenolic (24.61mg GAE/g DM in the peel and 2.01mg GAE/g DM in the pulp) and flavonoid compounds (24.95mg QE/g DM in the peel and 16.15mg E/g DM in the pulp). Antioxidant activity determined by ABTS, DPPH and FRAP assays in mango peel was significantly higher than in the mango pulp (24.95 1.96mg TE /g DM, 23.68 versus 4.60mg BHA/g DM and 40.52 versus 2.781mg TE/g DM), respectively. Results for scavenging activity against DPPH were 96.18% for the peel and 23.86% for the pulp, while, free radical scavenging activity results using ABTS+ assay were 99.62% in the peel and 13.46% in the pulp. Our study justifies research in processing of mango peel into useful, functional food ingredients (powders or extracts).