Assessment of antioxidant constituents and anti-oxidative properties of vegetable soybean

Abstract

Vegetable soybean is fast becoming a popular nutritious snack outside South-Eastern countries where its consumption is in vogue since ages. Reports have appeared in the literature concerning the nutritional value of green seeds; however, the information on its antioxidative properties is lacking. In the present investigation, 16 vegetable-type soybeans were evaluated for antioxidant constituents and antioxidative properties at picking stage. Vitamin C, total phenolic content, and total isoflavone were significantly different among different genotypes with ranges of 34.8–88.7 mg/100 g seed, 0.68–1.39 mg gallic acid equivalent/g, and 8.6–33.2 mg/100 g, respectively. ‘Dada-cha 2000’ had the highest total isoflavone followed by ‘ASG328 Sricanan’. Genotypic differences were also observed for antioxidative properties viz. ferric reducing antioxidative power, free radical-scavenging activities, and β-carotene bleaching inhibition. ‘Dada-cha 2000’ showed the highest ferric reducing antioxidative power value (10.9μmoles/g), while ‘Kegone’ showed the lowest (3.95μmoles/g). ‘Dada-cha ma-me’, ‘Dada-cha 2000’, ‘ASG328 Sricanan’, and ‘ASG328 Kohine’ exhibited the highest free radical-scavenging activities. ‘AGS439’ and ‘Dada-cha ma-me’ exhibited the highest values for β-carotene bleaching inhibition followed by ‘ASG328 Sricanan’. Correlation studies revealed significant positive correlation of ferric reducing antioxidative power and free radical-scavenging activities with individual forms of isoflavones and total isoflavone content.