Dynamic Viscoelasticity of Starch, Amylose, and Amylopectin Impregnated with Plasticizer

Abstract

Temperature dependence of the dynamic viscoelasticity of starch, amylose, and amylopectin impregnated with glycerin was measured to elucidate the structure of the gel prepared from dimethylsulfoxide solution. The results obtained from the X-ray diffraction pattern and the viscoelastic behavior are as follows. (1) Rigidity of amylose impregnated with glycerin lowers stepwise in the transition region, but the changes are small. The results show that the amylose gel forms a tight structure in spite of the lower crystallinity indicated by the X-ray diffraction method. (2) Rigidity of amylopectin impregnated with glycerin lowers remarkably in the transition region. The results show that the amylopectin gel forms a loose structure except the crystalline region. (3) The starch gel forms an intermediate structure between those of the amylose and the amylopectin gels.