Rheology and modelling of aqueous gum solutions commonly used in the food industry

Summary Rheological properties of solutions prepared using xanthan (XG), locust bean (LBG) or sodium carboxymethyl cellulose (CMC) gums, and their binary mixtures were studied. The influence of shear rate, total gum content, measurement time and temperature on the apparent viscosity was investigated. In the binary mixtures, the presence of different gum ratios at several total gum content was also analysed. XG solutions were always the most stable, providing high viscosity values which rose notably with increasing gum content. XG/LBG and CMC/XG mixtures depicted high values of viscosity for very low gum amounts. Viscosity did not change with measurement time in mixtures containing XG, whereas varied with measurement temperature. This variation was lower for samples with larger total gum content. The viscosity was also modified when different gum ratios were tested. A mathematical model was proposed to evaluate the combined effect of temperature, concentration and shear rate on the apparent viscosity.