Sensory perception of guar gum-induced thickening: Correlations with rheological analysis

Abstract

This work studies the connection between the orally-perceived thickness and easiness to swallow of guar gum dispersions with their shear and extensional rheological properties. The concentration dependence of the orally-perceived thickness scales with the decimal logarithm of the extensional viscosity. The easiness in swallowing, as perceived by sensory testers, is linked to the Trouton's ratio and scales with the logarithm of the extensional viscosity. The transition of the polymers to the semi-dilute regime leads to a marked change to the Trouton's ratio and, above 0.75 g dL−1, its value closes to 5. This study concludes that extensional, rather more than shear viscosity, is responsible for the perception of thickness and easiness in swallowing; however, at higher concentrations, both viscosities become of importance in the regulation of oral polysaccharide flow.