Preparation Process Optimization and Evaluation of Antioxidant Activity of Burdock Polysaccharide Zinc Complex

In this study, burdock polysaccharide zinc complex was synthesized by the zinc sulfate method with burdock polysaccharide and zinc sulfate as raw materials. Single factor and response surface methodology were used to optimize the preparation process of burdock polysaccharide zinc complex, and the antioxidant activity of burdock polysaccharide zinc complex was studied. The results showed that the optimum preparation process of burdock polysaccharide zinc complex was as follows: The weight ratio of burdock polysaccharide to zinc sulfate was 37:1, the temperature was 50 ℃, the time was 121 min and the pH was 8.6, the chelation rate was 93.21%±0.58%. The antioxidant test showed that when the concentration was 1.0 mg/mL, the scavenging rates of burdock polysaccharide zinc complex on DPPH radical, superoxide anion radical and ABTS⁺ radical were 84.59%±0.60%, 67.27%±1.00% and 38.88%±1.68%, respectively, which were better than burdock polysaccharide. However, the scavenging rate of hydroxyl radicals of burdock polysaccharide zinc complex was slightly lower than that of the burdock polysaccharide. The antioxidant capacity of burdock polysaccharide after zinc modification could be enhanced, and this work could provide a reference for the high value utilization of burdock polysaccharide.