反应挤出与酶法联合制备多孔淀粉工艺的优化

Optimized Preparation of Porous Starch by Reactive Extrusion Combined with Enzymolysis

以多孔淀粉吸油率为指标,利用Placket-Burman Design(PBD)试验、最陡爬坡试验和Box-Benhnken Design(BBD)试验对反应挤出与酶联合作用制备多孔淀粉工艺进行优化。结果表明,PBD试验得出影响多孔淀粉显著效应因素为物料水分含量、α-淀粉酶添加量、酶解时间、糖化酶添加量。通过最陡爬坡试验确定粉吸油率的九个因素进行评价,筛选出四个最大响应区域,并采用BBD试验优化了工艺。得出最佳配方工艺:物料水分含量36%、α-淀粉酶添加量0.52%、酶解时间7.7 h、糖化酶添加量1.73%,挤压温度70℃、螺杆转速120 r/min、pH5.0、酶解温度50℃、底物浓度25%,吸油率达到最大值68.49%,与预测值相近,较对照提高14.97%。扫描电子显微镜显示,反应挤出与酶联合作用与天然淀粉酶解法相比,其制备的多孔淀粉在孔的数量、孔径大小、分布均一性等方面都有着明显的优势。

In this study,porous starch was produced by reactive extrusion combined with enzymolysis.In order to analyze the effect of variables on the oil absorption rate of porous starch,the process of preparing porous starch was optimized by the Placket-Burman design,the steepest ascent design and the Box-Benhnken design.Results showed that,four significant variables were screened out(moisture content,concentration of α-amylase,enzymolysis time,and concentration of glucoamylase)from nine related variables by Placket-Burman design.The maximum response area was determined by the steepest ascent design.The optimal parameter level of main significant variables was determined by Box-Benhnken design(BBD).An optimized formulation was as follows:The moisture of material was 36%,concentration ofα-amylase was 0.52%,time of enzymolysis was 7.7 h,the concentration of glucoamylase was 1.73%,the temperature of barrel was 70℃,the speed of screw was 120 r/min,enzymolysis pH was 5.0,the temperature of enzymolysis was 50℃ and the substrate concentration was 25%,the oil absorption rate reached a maximum of 68.49%,which was similar to the measured value,and 14.97% higher than that of the control.The images of scanning electron microscopy demonstrated that,compared with the natural starch enzymolysis method,the combination of reactive extrusion and enzyme had obvious advantages in the number of pores,pore size and uniformity of distribution.