Plant proteins from Semen Astragali Complanati: Functional and physicochemical properties and antioxidant activity

Abstract

Semen Astragali Complanati (SAC) as a legume is rich in protein. However, due to the lack of investigation into its protein composition and functional properties, SAC protein remains underutilized. The aim of this study was to determine potential applications of SAC protein in the food industry. Albumin, globulin, prolamin, and glutelin were obtained for the first time from defatted SAC powder by using an Osborne extraction and chemical and cellular antioxidant methods, and their physicochemical and functional properties, and antioxidant activity were determined. In terms of functional properties, glutelin showed the best characteristics overall among the four proteins. In terms of physicochemical properties, the low molecular weight glutelin was observed to have a smoother surface under scanning electron microscopy and a higher solubility and emulsifying capacity at different pH values among the four protein fractions. The main secondary structures of the protein fractions were α-helices and β-sheets, and the crystallinity ranged from 14.28% to 33.76%, indicating amorphous internal structural features. The antioxidant results showed that glutelin demonstrated better free radical scavenging ability. In conclusion, the glutelin in SAC demonstrated notable functional properties and antioxidant activities, and it is promising for future development and application in functional foods and health foods. • SAC protein fractions can be used as a novel protein in food products. • SAC protein fractions are studied for the first time. • Glutelin in SAC can be employed as a natural antioxidant.

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