Abstract

SCREENING OF DIFFERENT BANANA PEELS EXTRACTS FOR ANTIOXIDANT CAPACITY AND TOTAL PHENOLS.

Sathish Kumar*

Abstract

The total phenolic content and related total antioxidant capacity of 4 types of banana peels were analyzed. The banana varieties belonging to Karpooravalli (Musa spp. - Karpooravalli - ABB), Musa acuminata viz., Pach- ainadan (Musa spp. - Pachanadan - AABS), Poovan (Musa spp. - Mysore - AAB), Rasthali (Musa spp. - Rast-hali - AAB). Those Banana peels extracts obtained in this work had a high capacity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3- ethylbenzothiazoline)-6-sulfonic acid (ABTS+) free radicals NBR(Nitro blue tetrazolium), and they were also good lipid peroxidation inhibitors. Acetone: water extracts were considerably more effective (compared with methanol, ethanol, acetone, water, methanol: water or ethanol: water) at inhibiting the peroxidation of lipids in the β-carotene/linoleic acid system or scavenging free radicals. However, aqueous extracts had a high capacity to protect lipids from oxidation in the thiobarbituric acid reactive substances (TBARS) test, as well as in the β-carotene bleaching assay. To make practical comparison of relative antioxidant potential of phenolics extracted from selected banana peels, the phenol antioxidant coefficient(PAC) was calculated for each infusion. In addition, acetone :water most efficiently extracted all extractable components (54 ± 4%), phenolic compounds (3.3 ± 0.8%), and anthocyanin compounds (434 ± 97 μg cyanidin 3-glucoside equivalents/100 g freeze-dried banana peel). Banana peel contained large amounts of dopamine and L-dopa, catecholamines with a significant antioxidant activity. However, ascorbic acid, tocopherols or phytosterols were not detected in the different extracts. The antioxidant activity of banana peel extracts from different cultivars was similar. However, the impact of extraction time or temperature should be studied in greater depth.

Keywords: Frap; Dpph; Abts, Nbt.