复合酶法修饰糯米淀粉分支结构及其物化性能研究

Physico-chemical properties and branch structure of the waxy rice starch modified by using compound enzymes

中文关键词:  糯米淀粉  复合酶法  物化性质  分支度

英文关键词:waxy rice starch  dual-enzyme modification  physicochemical properties  branch degree

中文摘要:

      目的 提高糯米淀粉的物化性质及其加工性能。方法 以糯米淀粉为受体, 以不同直链淀粉(小麦、玉米、大米)或麦芽糖为供体, 采用α-淀粉酶和分支酶复合酶, 对糯米淀粉进行分子结构修饰, 测定改性前后糯米淀粉的分支度、溶解度、糊化和老化性质。结果 糯米淀粉通过复合酶法改性能够显著地提高改性淀粉的分支度; 改性后的淀粉易于糊化, 且糊化液的均匀性和透明度较好。通过DSC测定改性前后热力学性质, 发现改性淀粉未出现吸收峰, 表明淀粉结晶区中的长链被破坏, 从而形成高短链数的改性淀粉; 淀粉经过改性后得到可溶性淀粉。结论 糯米淀粉加入供体物质, 通过复合酶对淀粉进行改性, 能够提高改性淀粉的分支度和短链数, 制备出具有良好物化特性的改性淀粉。

英文摘要:

      Objective To improve the physico-chemical properties and processability of waxy rice starch. Methods The molecular structure of waxy rice starch was modified by the combination of α-amylase and branching enzyme, with waxy rice starch as receptor and different amylose (wheat, corn, rice) or maltose as donors. The branching, solubility, gelatinization and aging properties of waxy rice starch before and after modification were determined. Results The dual-enzymatic modification could obviously enhanced the branching degree of waxy rice starch; Comparison to native waxy rice starch, the modified waxy rice starches were easier to be gelatinized, and the gelatinized paste excellent better uniform and transparent. The thermodynamic property of the modified starch was studied using a differential scanning calorimetry. It indicated that the modified starches showed no endothermic peak. This might because the long chains in the starch crystalline were destroyed, thus forming a high number of short chains; Compared to native waxy rice starch, the solubility of the modified waxy rice starches increased to obtain soluble starch. Conclusion Adding the donor substance to the glutinous rice starch and modifying the starch by the complex enzyme can increase the branching degree and short chain number of the modified starch, and prepare the modified starch with good physicochemical properties.