Suppressive effect of extruded adzuki beans (Vigna angularis) on hyperglycemia after sucrose loading in rats

• Extruded adzuki beans protein significantly inhibited rat intestinal a-glucosidases.
• Animal study revealed that the oral intake of extruded adzuki beans extract (EABE) significantly reduced postprandial blood glucose.
• The content of protein in extruded adzuki beans is 20.99%.

Extrusion process has been widely used for the development of many functional foods. The aim of this study was to assess the effect of extrusion process on antioxidant and α-glucosidases inhibition properties of adzuki beans. The results showed that there were no significant differences of polysaccharide content, protein content, and total flavonoid content (TFC) between adzuki beans extract (ABE) and extruded adzuki beans extract (EABE). However, a significant decrease in the total phenolic content (TPC) was observed. The antioxidant activity determined by a method based on the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) radical-scavenging activity also decreased significantly after extrusion. This study, for the first time, identified that extruded adzuki beans protein (10 mg/mL) significantly inhibited rat intestinal α-glucosidases (60.44%). Further animal study revealed that the oral intake of EABE (300 mg/kg) significantly reduced postprandial blood glucose by 15.6% and 30.9% following sucrose challenge in the normal and streptozocin-treated rats, respectively. The results demonstrated that the potential for the extruded food products with the improved antidiabetic activity from adzuki beans.