Antioxidant Activity and Tryptophan Content of Banana Peel

Agung Banana (Musa paradisiaca L. var Semeru) is a superior banana variety from Lumajang, East Java. This study aims to determine the total phenolic content, radical scavenging activity, tryptophan content of Agung banana peel powder, and banana peel ethanol extract (BPE). BPE�s free radical scavenging activity was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Total phenolic content was tested using the Folin-Ciocalteu reagent. The tryptophan content was analyzed using HPLC. The concentration of the sample that could scavenge 50 of DPPH free radicals (IC50) of BPE was 684.69 ± 120.73 ppm, and the antioxidant activity index was 0.37 ± 0.07. The total phenolic content of BPE was 17.41 ± 0.14 gallic acid equivalents (GAE) mg/g. There was no significant correlation between total phenolic content (TPC) and IC50 value (r =-0.269, p > 0.05). The tryptophan content of BPE was 0.02 w/w. DPPH assays of BPE showed that their antioxidant activity was weak. The phenolic content of the BPE did not significantly contribute to their antioxidant activities. The tryptophan content of BPE was not as high as expected. © 2023, Thai Society of Higher Eduation Institutes on Environment. All rights reserved.