Study of xanthan gum/waxy corn starch interaction in solution by viscometry

The objective of the study was to investigate the molecular interactions of xanthan gum and waxy corn starch in a ternary system. Solutions of xanthan gum/(waxy corn starch) blends dissolved in a mixed solvent of 90% DMSO/10% H2O (v/v) were studied by means of viscometry as a function of total polymer concentration and composition. The classical Huggins equation, ηsp/C=[η]+bC, which expresses the specific viscosity (ηsp) of a polymer as a function of the concentration C, was found to be suitable for all blends in the dilute system. The intrinsic viscosity ([η]) and Huggins parameter b of the blends increased with the increase of xanthan fraction in the blends. Meanwhile, the addition of xanthan gum also dramatically lowered the overlap concentration (C*) of the blends. The results indicate that xanthan gum is a good thickener, and xanthan gum and waxy corn starch are attracted to each other in the solution under study.