Tissue-Specific Metabolic Profiling of Mungbean (Vigna radiata L.) Genotypes with Different Seed Coat Colors

Abstract

Mungbean (Vigna radiata L.) is one of the major legume crops containing high carbohydrate and protein contents. In this study, the total phenolic and flavonoid contents and ABTS/DPPH radical scavenging activity of whole sprouts and seed coats were evaluated by using 10 mungbean genotypes with diverse seed coat colors and origins. Qualitative/quantitative analysis of individual secondary metabolites was performed with ultrahigh performance liquid chromatography (UPLC). Overall, 23 polyphenols, including flavonoids, phenylpropanoids, and anthocyanins, were identified. Depending on genotypes, significant variations in the contents of each phytochemical were identified before/after germination. The results indicate that the specific pathways of phenolic compounds, including chlorogenic acid, coumestrol, genistein, and glycitein, are activated by sprouting in mungbean. The neo/chlorogenic acid contents had tissue specificity, even though it was isomeric. The anthocyanin contents were higher in green and yellow mungbeans than in black mungbeans. These findings in this study will provide valuable information to improve the food quality of mungbean sprouts with high polyphenolic contents.