响应面法优化硒化桑叶多糖的制备工艺及其体外抗氧化活性  

Optimization of selenized mulberry leaf polysaccharides preparation by response surface methodology and determination of the antioxidant activity in vitro

作　　者：胡润锋 李浚哲 李鹏飞[2,3] 周军[1] 李湘洲[1] HU Runfeng;LI Junzhe;LI Pengfei;ZHOU Jun;LI Xiangzhou(School of Materials Science and Engineering,Central South University of Forestry&Technology,Changsha 410004,Hunan,China;Guangxi Key Laboratory of Chemistry and Engineering of Forest Products,Guangxi University for Nationalities,Nanning 530006,Guangxi,China;b.Guangxi Collaborative Innovation Center for Chemistry and Engineering of Forest Products,Guangxi University for Nationalities,Nanning 530006,Guangxi,China)

机构地区：[1]中南林业科技大学材料科学与工程学院,湖南长沙410004 [2]广西民族大学广西林产化学与工程重点实验室,广西南宁530006 [3]广西民族大学广西林产化学与工程协同创新中心,广西南宁530006

出　　处：《中南林业科技大学学报》2022年第8期148-157,共10页Journal of Central South University of Forestry & Technology

基　　金：国家重点研发计划项目(2016YFD0600805);广西林产化学与工程重点实验室开放项目(GXFG2007);国家级大学生创新创业训练计划项目(S202010538014)。

摘　　要：【目的】优化硒化桑叶多糖的制备工艺,获得抗氧化活性更高的硒化桑叶多糖。【方法】以硒含量为指标,利用HNO_(3)-Na_(2)SeO_(3)法对桑叶多糖(MLP)进行硒化修饰制备硒化桑叶多糖(MLP-Se),单因素实验分别考察Na_(2)SeO_(3)与MLP的质量比、HNO_(3)体积分数、反应温度和反应时间对制备的MLP-Se中硒含量的影响,进一步利用响应面法优化MLP-Se的制备工艺。对MLP和MLP-Se进行扫描电镜-能谱(SEM-EDS)分析、凝胶色谱(GPC)分析、粒径和zeta电位分析、红外光谱(FT-IR)分析,探究硒化改性对桑叶多糖结构的影响,最后还研究了MLP和MLP-Se的体外抗氧化活性。【结果】制备MLP-Se的最佳工艺条件为反应时间7 h、反应温度85℃、HNO_(3)体积分数0.54%、Na_(2)SeO_(3)与MLP的质量比1.27,此条件下制备的MLP-Se中硒含量为3.147 mg·g^(-1),建立的响应面模型可用于分析预测MLP-Se的制备;SEM-EDS分析表明硒化修饰改变了MLP的表观形貌且MLP-Se中存在硒元素;GPC分析表明MLP和MLP-Se的相对分子质量分别为2.099×10^(3)和2.385×10^(3) kDa,硒化修饰增大了MLP的分子量;硒化修饰后桑叶多糖的粒径减小,zeta电位绝对值增大,硒化修饰提高了MLP在溶液体系中稳定性;FT-IR分析表明MLP已被成功硒化,且硒与多糖是通过C-O-Se和Se=O结合;体外抗氧化活性分析表明硒化修饰可以提高MLP的抗氧化能力,MLP-Se对DPPH自由基和ABTS自由基的IC_(50)值分别为0.883和0.681 mg·g^(-1),明显低于MLP对DPPH自由基和ABTS自由基的IC_(50)值2.157和1.792 mg·g^(-1)(P<0.05)。【结论】硒化修饰可以改良MLP的理化性质,提高MLP的抗氧化能力,研究有利于桑叶多糖在功能性食品、保健品和药物等领域的开发利用。【Objective】This work aimed to obtain selenized mulberry leaf polysaccharides with higher antioxidant activity by optimizing the preparation process.【Method】Taking selenium content as an index,the effects of the mass ratio of Na_(2)SeO_(3) to MLP,the volume fraction of HNO_(3),reaction temperature and reaction time on the selenium content of the prepared MLP-Se were investigated by single factor experiment,and the optimal preparation conditions of MLP-Se were obtained by response surface methodology.The effects of selenization modification on the structure of mulberry leaf polysaccharides were investigated by SEM-EDS,GPC,particle size and zeta potential and FT-IR analysis.Finally,the antioxidant activities of MLP and MLP-Se were studied in vitro.【Result】The optimal conditions were:the reaction time of 7 hours,the reaction temperature at 85℃,a mass ratio of Na_(2)SeO_(3) to MLP of 1.2 and a 0.54%volume fraction of HNO_(3).Under the optimized extraction conditions,the selenium content of MLP-Se was 3.147 mg·g^(-1).The established response surface model can be used to analyze and predict the preparation of MLP-Se.SEM-EDS analysis showed that selenization modified the morphology of MLP and proved the presence of selenium in MLP-Se.GPC analysis showed that the molecular weight of MLP and MLP-Se were 2.099×10^(3) kDa and 2.385×10^(3) kDa,respectively.Selenization increased the molecular weight of MLP.The grain size of mulberry leaf polysaccharides decreased and the absolute value of zeta potential increased after selenization modification,which improved the stability of MLP in the solution system.FT-IR analysis showed that MLP had been selenized successfully,and selenium and polysaccharides were bound by C-O-Se and Se=O.The in vitro antioxidant activity experiments showed that selenization modification could improve the scavenging ability of DPPH free radical and ABTS free radical.The IC_(50) values of MLP-Se against DPPH free radical and ABTS free radical were 0.883 mg·g^(-1) and 0.681 mg·g^(-1),resp

关 键 词：桑叶多糖 硒化改性 响应面法 理化性质 抗氧化活性 

分 类 号：S789[农业科学—林学] TS201.2[轻工技术与工程—食品科学]