不同分子质量硒化葡聚糖的制备及其抗氧化活性分析

Preparation and Antioxidant Activity Analysis of Selenized Dextran with Different Molecular Weights

为了探究分子质量对硒化葡聚糖(Se-DEX)结构和抗氧化活性的影响。以70、200、500 kDa三种分子质量的葡聚糖(Dextran,DEX)及亚硒酸钠(Na_(2)SeO_(3))为原料,采用硝酸-亚硒酸钠(HNO_(3)-Na_(2)SeO_(3))法制备不同分子质量的Se-DEX;利用傅里叶变换红外光谱(FTIR)和紫外光谱(UV)对其结构进行表征,并以VC为阳性对照,分析不同分子质量Se-DEX的抗氧化活性。结果表明:FTIR显示Se-DEX中有硒酸酯键吸收峰出现,UV显示DEX硒化前后发生了吸收峰偏移,说明3种分子质量的DEX均被成功硒化;体外抗氧化活性试验表明,3种分子质量的Se-DEX对1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)自由基、羟基自由基及2,2’-联氨-双-3-乙基苯并噻唑啉-6-磺酸(2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)阳离子自由基均表现出较好的清除能力,均高于对应的DEX,并且存在剂量依赖关系,其中低分子质量的Se-DEX表现出较好的抗氧化活性。研究结果可为硒化葡聚糖应用于食品保鲜提供一定的技术指导和理论参考。

To investigate the effect of molecular weight on the structure and antioxidant activity of selenide dextran(Se-DEX),different molecular weights of Se-DEX were prepared by the nitric acid-sodium selenite(HNO_(3)-Na_(2)SeO_(3))method,using dextran(Dextran,DEX)with three molecular weights of 70 kDa,200 kDa,and 500 kDa and sodium selenite(Na_(2)SeO_(3))as raw materials.Characterization of its structure was performed using Fourier-transform infrared(FTIR)spectroscopy and ultraviolet spectroscopy(UV),with vitamin C(VC)serving as a positive control,to analyze the antioxidant activity of Se-DEX of different molecular weights.The results showed that the selenium ester bond absorption peak in Se-DEX was confirmed by FTIR,and a shift in the absorption peak occurred before and after DEX selenization,as verified by UV,indicating that all three molecular weight DEXs were successfully selenized.The in vitro antioxidant activity test showed that Se-DEX with three different molecular weights all exhibit good scavenging capabilities against DPPH radicals,hydroxyl radicals,and ABTS cation radicals,all of which were higher than the corresponding DEX and there was a dose-dependent relationship.Among them,the low molecular weight Se-DEX demonstrated better antioxidant activity.The research results could provide certain technical guidance and theoretical references for the application of selenized dextran in food preservation.