Anti-oxidant and anti-fatigue properties of polysaccharides from black soybean hull

Black soybean hull, as main by-production in black bean processing, has significant biological activity. In this study, the polysaccharide from black soybean hull (BSPS-H) was obtained by enzymatic hydrolysis, the yield was 5.3%, and its chemical composition and structural composition were further studied. The results shown that BSPS-H was mainly composed of Mannose, Galactose, and Glucose (molar ratio = 48.1: 29.7: 15.8), and might be existed in the form of pyran ring in α/β-linkage type. The anti-oxidant activity shown that BSPS-H had a certain capacity of anti-oxidation in a concentration-dependent manner. Among them, it has the best scavenging effect on DPPH free radicals. When the polysaccharide concentration was 10 mg/ml, the scavenging rate reached 94.37%. The results of anti-fatigue effect indicated that BSPS-H could prolong the duration of exhaustive swimming in mice, increased the contents of liver glycogen, reduced the content of blood urea nitrogen (BUN), enhanced the activity of lactate dehydrogenase (LDH) and reduced the accumulation of lactic acid (LA). This study provides a fundamental basis for the development and use of BSPS-H in medicine and functional foods.