牛蒡多糖锌的制备工艺优化及其抗氧化活性评价

本研究以牛蒡多糖和硫酸锌为原料，通过硫酸锌法合成牛蒡多糖锌。采用单因素实验和响应面试验优化牛蒡多糖锌的制备工艺，并对其抗氧化活性进行研究。结果表明：牛蒡多糖锌的最佳制备工艺为：牛蒡多糖与硫酸锌的质量比为37:1、温度50℃、时间121 min、pH8.6，此时螯合率为93.21%±0.58%。抗氧化试验表明：当浓度为1.0 mg/mL时，牛蒡多糖锌对DPPH自由基、超氧阴离子自由基和ABTS+自由基的清除率分别为84.59%±0.60%、67.27%±1.00%、38.88%±1.68%，自由基清除能力均优于牛蒡多糖；而牛蒡多糖锌对羟基自由基的清除率略低于牛蒡多糖。锌修饰牛蒡多糖可增强牛蒡多糖的抗氧化能力，为牛蒡多糖的高值化利用提供了参考。

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.