从糯米、籼米和粳米3种类型大米中分离提取支链淀粉，采用特征黏度法和激光光散射法研究支链淀粉在二甲亚砜（DMSO）纯溶液和DMSO水溶液中的分子构象。结果表明：籼米、粳米支链淀粉的分子特性较为相似，均与糯米支链淀粉的分子特性有较大差异。以糯米支链淀粉的重均分子质量和旋转半径最大，分支度最高，交点质量浓度最小，分子链更易伸展。大米支链淀粉在DMSO中的分子构象与DMSO水溶液的体积分数以及自身的重均分子质量、分支度和质量浓度有关。在DMSO纯溶液中，大米支链淀粉的分子构象接近球形。在DMSO水溶液中，籼米和粳米支链淀粉的分子构象几乎不受自身质量浓度影响，均接近星形；而糯米支链淀粉分子构象受自身质量浓度影响较大，在极低质量浓度条件下表现为硬球结构，稍高质量浓度条件下表现为柔性球结构。%The molecular conformation of amylopectin from glutinous rice, indica rice and japonica rice in DMSO pure or aqueous solution was studied by intrinsic viscosity test and laser scattering （LS）. The results showed that amylopectin from indica rice and japonica rice had similar molecular characteristics which were different from those of glutinous rice. Amylopectin from glutinous rice had the maximum molecular weight and rayleigh ratio, highest degree of branching and lowest overlap concentration with highly extendable molecular chain. The molecular conformation of amylopectin in DMSO was related to DMSO concen- tration its aqueous solution and the average molecular weight, degree of branching and concentration of amylopectin. The molecular conformation of rice amylopectin was almost spherical structure in neat DMSO. In DMSO aqueous solution, the molecular conformation of amylopectin from glutinous rice was greatly affected by its concentration, which displayed rigid spheres at very low concentration and flexible sphere at increased concentration. Amylopectin from indica rice and japonica rice was scarcely affected by its concentration and displayed the shape of more rigid star.
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