Metabolic profiling and antioxidant properties of hybrid soybeans with different seed coat colors, obtained by crossing β-carotene-enhanced (Glycine max) and wild (Glycine soja) soybeans

We obtained new hybrid soybeans (Hybrid) with different seed coat colors such as green (Hybrid-GR), brown (Hybrid-BR), yellow (Hybrid-YE), and black (Hybrid-BL), by hybridizing β-carotene-enhanced soybeans (BCE; Glycine max L.) containing the phytoene synthase-2A-carotene desaturase gene and wild soybeans (Wild; Glycine soja). This study aimed to analyze metabolic changes between Hybrids using comprehensive metabolite profiling of BCE, Wild, and four Hybrids. The composition and content of metabolites varied based on the type of soybeans. Multivariate and metabolic pathway analyses showed distinct differences among the six soybeans. Hybrid-GR showed accumulation of isoflavones and tocopherols, whereas Hybrid-BL had higher contents of anthocyanins and carotenoids than other Hybrids. The projection to latent structure analysis showed that the most important contributors in enhanced free radical scavenging activity were phenolic compounds such as anthocyanins and flavonoids and isoprenoids such as carotenoids, tocopherols, and phytosterols, assessed using 2,2-diphenyl-1-picrylhydrazyl and 2,2´-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays, respectively. Based on these results, Hybrid-GR and Hybrid-BL comprising significant quantities of functional compounds such as isoflavones, carotenoids, and anthocyanins are proposed as new breeding candidates.