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.
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