Multivariate Evaluation of Biofunctional Metabolites in Korean Soybean Cultivars by Use Categories: Assessment of Antioxidant and Enzyme Inhibition Activities

Abstract

This research investigates the metabolite composition and biofunctional activiteies of 41 Korean soybeans, categorized by application: bean sprout, bean paste, vegetable, and cooked-with-rice. Isoflavones were identified via UPLC-Q-TOF-MS/MS and quantified using HPLC, revealing malonylgenistin as the predominant composition (average 743.4 mu g/g, 42.3% of total isoflavones). Bean sprout showed the highest average isoflavone (2780.6 mu g/g), followed by bean paste (1837.8 mu g/g), cooked-with-rice (1448.2 mu g/g), and vegetable (883.2 mu g/g), with significant differences in individual cultivars. Protein ranged from 36.8 to 46.6% and oil from 17.0 to 22.3%, with vegetable soybeans exhibiting the highest average protein (44.9%) and lowest average oil (18.6%). Moreover, PLS-DA and hierarchical clustering revealed distinct metabolic patterns in usage groups. Antioxidant activities (radical scavenging; DNA protection) and enzyme inhibition (tyrosinase; alpha-glucosidase) also varied significantly, correlating with isoflavone distributions. Particularly, Sorog exhibited the highest isoflavone (3722.7 mu g/g) and strong antioxidant activity (DPPH: 72.2%; ABTS: 93.8%, 500 mu g/mL), DNA protection (92.8%, 200 mu g/mL), and inhibition of tyrosinase and alpha-glucosidase by 78.4% and 84.2% (500 mu g/mL). These findings suggest that isoflavone-rich bean sprout soybeans, especially Sorog, are promising candidates for health-promoting foods and functional cultivar development. This is the first systematic study comparing the metabolites and health-related properties of soybeans based on Korean usage categories.