Antioxidant activity of onion (allium cepa l.) peel extracts obtained as onion byproducts

Abstract

This study investigated the antioxidant activity of onion peels extracted from onion byproducts by hot water treatment. Hot water extraction of freeze dried onion peel powder was analyzed for total polyphenol content, 2,2′-diphenyl-1-picryllhydrazyl (DPPH), and 2,2′-azino-bis(3- ehtylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, reducing power, oxygen radical absorbance capacity (ORAC). Total polyphenol content was the highest (233.90 mg/g) in onion peel extract mix with ethanol (OPME-1). The DPPH radical scavenging activity (IC50), reducing power, and ORAC obtainbed from onion peel extract mix with ethanol precipitation (OPMPE-1) were the highest at 1.15 mg/mL, 1.69 A700, and 318,509 μM TE/mL, respectively. The ABTS radical scavenging activity was the highest at 432.78 mg amino acids (AA) eq/g in the OPM. The results of this study suggest that onion peel extracts have marked antioxidant activity, which can have significant health benefits. © The Korean Society of Food Science and Technology.