Comparative Assessment of Nutritional Metabolites in Yellow Soybeans at Different Growth Years and Their Antioxidant and α-Glucosidase Inhibition Properties

Abstract

With regard to obtaining valuable information on the development of new breeding lines and functional agents, the present study was the first to demonstrate variations in nutritional metabolites and biological properties in yellow soybeans at three growth years. Three metabolites (fatty acid, amino acid, isoflavone) exhibited significant differences between cultivars and growth years; specifically, linoleic acid, glutamic acid, and malonylgenistin displayed the highest average contents at 38.7 mg/g, 59.9 mg/100 g, and 992.6 μg/g, exhibiting predominant changes in the range of 21.6–61.2 mg/g, 34.3–113.3 mg/100 g, and 455.8–1778.9 μg/g, respectively. Moreover, the biofunctional effects differed remarkably in the order ABTS > α-glucosidase > DPPH at 500 μg/mL (50% methanol extracts). The TPC, TFC, DNA protection, and FRAP ratios also showed remarkable changes in cultivars across growth times. Interestingly, the Daepung cultivar may be considered an alternative source for the development of new soybeans and nutraceutical foods due to its high metabolites (average contents, fatty acid: 80.8 mg/g; amino acid: 353.8 mg/100 g; isoflavone: 4048.2 μg/g) and excellent beneficial activities (75.1% ABTS, 52.5% DPPH, 100% DNA protection, 73.1% α-glucosidase, 1.54 OD593 nm FRAP at 500 μg/mL). Our observations may contribute to providing valuable information on the relationship between metabolites and the biological properties of yellow soybeans.