Abstract: 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 concentration 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.

Key words: rice amylopectin, neat DMSO, DMSO aqueous solution, molecular conformation