Antioxidants and Pungency of Onion

Abstract

Information on levels of antioxidants and pungency can be utilized for improvement of onion (Allium cepa L.) through selection or breeding. Several genotypes were evaluated for these criteria. Phenol (128.51 mg/100 g) was found to be the most abundant antioxidant followed by ascorbic acid (11.49 mg/100 g). Superoxide dismutase, peroxidase, and catalase activities averaged as 4.80 mg·mL−1, 1.71 ΔA430·min−1·g−1, and 0.73 units, respectively. Antioxidant capacity, as determined by ascorbic acid and quercetin equivalents, was highest in ‘AVT-II(01)’ and ‘Sukhsagar’, whereas that determined by 2,2-diphenyl-β-picrylhydrazyl radical scavenging activity was highest (i.e., the lowest IC50 value) in ‘AVT-I(05)’. Lipid peroxidation, an indirect measure of antioxidant capacity, ranged between 0.019 and 0.036 μmol of malondialdehyde/100 g of substrate. Pyruvic acid development, an index of onion pungency, was between 6.86 and 15.33 μmol·g−1. Based on averages and principal component analysis, genotype ‘AVT-I(03)’ followed by ‘AVT-II(01)’ and ‘Sukhsagar’ can be used for future breeding programs.