Preparation, characteristics and antioxidant activity of mung bean peel polysaccharides

The mung bean peel polysaccharide (MBP) extracted by hot water was chemically modified. By changing the dosage of phosphorylation reagent and acetylation reagent, three kinds of phosphorylated MBP ( P-MBP-1, P-MBP-2, P-MBP-3 ) and acetylated MBP ( AC 0.6-MBP, AC 1-MBP, AC 1.4-MBP ) with different degrees of substitution were prepared. By measuring the sugar content and substitution degree of the modified products, it was found that the amount of reagent had a certain effect on both of them. The modified products were determined by infrared spectrum and nuclear magnetic resonance. The results showed that the chemical modification was successful. The in vitro antioxidant capacity (·OH scavenging ability, O₂^-·clearing ability, reducing capacity, resistance to lipid peroxidation) of seven polysaccharide were measured, which manifested that chemical modification could enhance the antioxidant ability of MBP to varying degrees, and the DS also had a certain impact on their antioxidant activity. This promoted the development of mung bean peel polysaccharide functional products and the utilization of mung bean peel resources.