Variations of Major Flavonoids, Nutritional Components, and Antioxidant Activities in Mung Beans (Vigna radiate L.) of Different Seed Weights

This study examined the levels of major flavonoids, nutritional components, total secondary metabolite contents, and antioxidant activities in 136 mung bean accessions and statistically analyzed the effect of seed weight difference on each. Vitexin and isovitexin were detected in all the mung bean accessions, with isovitexin being in a higher concentration regardless of seed weight difference. The contents of total protein and total starch were in the ranges of 22.01-28.96 and 32.62-49.03 g/100 g, respectively. Five fatty acids were detected by GC-FID analysis in all mung bean accessions, with linoleic acid being the most dominant (37.96-50.71 g/100 g). Total saponin content (TSC), total phenol content (TPC), DPPH^• scavenging activity, ABTS^•+ scavenging activity, and ferric reducing antioxidant power (FRAP) showed more than five-fold differences. Analysis of variance supported by multivariate analysis demonstrated that seed weight difference had a significant effect on total starch, all individual fatty acids except for stearic acid and oleic acid, TSC, and all antioxidant activities except for ABTS^•+ scavenging activity. On the other hand, vitexin, isovitexin, total protein, total phenol, and total fatty acid contents remained unaffected by seed weight difference. Overall, this study showed the diversity of key flavonoids, nutritional components, total secondary metabolite contents, and antioxidant activities in mung bean genetic materials. Moreover, the study unveiled how seed weight affects the analyzed parameters in mung beans for the first time. These findings could maximize the use of mung beans in food industries and breeding programs as well as lead to more studies in metabolomics and genomics.