干与鲜马齿苋多糖抗氧化动力学研究

Study on antioxidant kinetics of dried and fresh Portulaca oleracea polysaccharides

分别采用新鲜和干制马齿苋酶解提取马齿苋多糖,比较干、鲜马齿苋多糖的得率和抗氧化性。结果表明:鲜榨马齿苋多糖的提取率为12.51 g/kg(鲜计),干制马齿苋多糖的提取率为4.88 g/kg(鲜计),鲜马齿苋多糖提取率远高于干马齿苋多糖的提取率。多糖质量浓度为1.196 g/L,在反应2 min时干马齿苋多糖对OH自由基的清除率为53.4%,鲜马齿苋多糖为68.4%;在反应60 min时干马齿苋多糖对Ce(Ⅳ)还原率为66.2%,鲜马齿苋多糖为69.2%。干、鲜马齿苋多糖清除OH自由基和还原Ce(Ⅳ)的能力均随质量浓度的增大而增大,鲜马齿苋多糖的抗氧化性强于干马齿苋多糖,反应均接近一级反应动力学方程。

Portulaca oleracea polysaccharides( POPs) were extracted from fresh and dried Portulaca oleracea L. by enzymolysis,and the yield and antioxidant activity of polysaccharides were compared between dry and fresh Portulaca oleracea L.. The results showed that the extraction rate of fresh POPs was12. 51 g/kg( fresh),and that of dry POPs was 4. 88 g/kg( fresh). The extraction rate of fresh POPs was much higher than that of dry POPs. When the reaction time was 2 min and the mass concentration of POPs was 1. 196 g/L,the scavenging rate of dry POPs to OH radical was 53. 4 %,and that of fresh POPs was 68. 4 %;When the reaction time was 60 min,the reduction rate of Ce( Ⅳ) was 66. 2 % for dry POPs and 69. 2 % for fresh POPs. The ability of scavenging OH radical and reducing Ce( Ⅳ) of dry and fresh POPs increased with the increase of mass concentration. The antioxidant activity of fresh POPs was stronger than that of dry POPs,and the reaction was close to the first-order kinetic equation.