硫酸酯化洋葱多糖的制备及其抗氧化活性的研究

Preparation and antioxidative activities of sulfated onion polysaccharides

以洋葱为原料,采用水提醇沉法制备洋葱多糖。用浓硫酸法对洋葱多糖进行硫酸酯法修饰,采用硫酸酯取代度为指标,对硫酸酯化反应的浓硫酸与正丁醇的体积比和反应时间进行优化,并对不同浓度的硫酸酯化洋葱多糖进行体外抗氧化实验。结果表明,制备硫酸酯化洋葱多糖的较佳工艺为浓硫酸和正丁醇体积比3∶1,反应时间20min和反应温度0℃,在此条件下多糖硫酸根取代度为0.51。同时,洋葱多糖硫酸酯化改性后可显著提高抗氧化性。

In this paper,polysaccharides were obtained by water extraction and alcohol precipitation from onions.The polysaccharides were then sulfated with concentrated sulfuric acid.The volume ratio of pyridine and sulfuric acid and the sulfuric reaction time were optimized by using the degree of substitution of sulfated onion polysaccharide as the index.The antioxidant activity of different concentrations of sulfated onion polysaccharide were also studied.The results indicated that when the sulfated reaction was performed under the conditions of volume ratio of sulfuric acid and n-butanol 3∶1,reaction for 20min at 0℃,the degree of substitution of sulfated onion polysaccharides was 0.51.Sulfated can significantly improve the antioxidant activities of onion polysaccharide.