【摘要】 以取代度为考察指标,研究了浓硫酸加入量、反应温度和反应时间等因素对平菇多糖硫酸化的影响;在单因素的基础上,通过L₉（3⁴）正交试验优化平菇多糖硫酸酯的制备工艺条件;采用FT-IR光谱仪对平菇多糖和平菇多糖硫酸酯进行结构鉴定,并通过测定还原力、DPPH自由基、超氧阴离子自由基和羟自由基清除率探索了平菇多糖硫酸酯的抗氧化活性。结果表明:平菇多糖硫酸酯制备优化工艺条件为平菇多糖1.00g,浓硫酸加入量10mL,反应温度60℃,反应时间90min,该条件下平菇多糖硫酸酯的取代度为0.48。FT-IR光谱分析证明硫酸基与平菇多糖形成了平菇多糖硫酸酯。平菇多糖硫酸酯对DPPH自由基、超氧阴离子自由基和羟基自由基的IC₅₀（半数清除率）分别是0.816,1.882,1.611mg/mL;平菇多糖硫酸酯的还原力和对3种自由基的清除力均优于平菇多糖。说明平菇多糖经硫酸酯化后抗氧化能力增强。更多还原

【Abstract】 Taking substitution rate as an index,the effects of concentration of sulfuric acid,reaction temperature and reaction time on sulfation of Pleurotus ostreatus polysaccharides were studied by concentrated sulfuric acid method.On the basis of single-factor results,the optimum preparation process of P.ostreatus polysaccharide sulfate was obtained by L₉（3⁴） orthogonal test.Secondly,the polysaccharide and sulfates of P.ostreatus polysaccharide were characterized by FT-IR spectrometer.Finally,the reductive power of VCandthe scavenging rates of DPPH radical,superoxide anion radical and hydroxyl radical were determined to explore the antioxidant activity of P.ostreatus polysaccharide sulfate.The optimum preparation process of polysaccharide sulfate of P.ostreatus was as follows:the mass of P.ostreatus polysaccharide was 1.00 g;the volume of sulfuric acid was10 mL,reacting at 60℃for 90 min,and the degree of substitution was 0.48.FT-IR spectrum results showed that sulfate group and P.ostreatus polysaccharide formed polysaccharide sulfate.The IC₅₀（scavenging rate）of polysaccharide sulfate fromP.ostreatus were 0.816,1.882 and 1.611 mg/mL for DPPH radical,superoxide anion radical and hydroxyl radical,respectively.The reductive power and scavenging ability to three free radicals of P.ostreatus polysaccharide sulfate were higher than those of polysaccharides,which suggested that P.ostreatus polysaccharide sulfate had a better antioxidant activity than that of polysaccharides.更多还原