Cohesiveness visual evaluation of thickened fluids

Cohesiveness is recognized as an important property of food for medical management of individuals who suffer from swallowing difficulty (known as dysphagia). However, while the term cohesiveness is commonly used for description of such products, its sensory nature and instrumental assessment remain a big challenge. Therefore, our aim in this work was to compare and correlate the rheological parameters of thickened fluids with the perceived cohesiveness obtained from the sensory analysis by visual perception. Thirty-two participants were recruited for this study to evaluate the cohesiveness of ten samples of thickened water prepared with different commercial food thickeners. Four rheological parameters (shear viscosity, yield stress, shear modulus, maximum extensional viscosity) of the samples were measured and correlated with the perceived cohesiveness obtained from the visual perception. It was observed that the maximum extensional viscosity is the most-well correlated with the cohesive properties as evaluated by the visual perception and could be used as a feasible indication of fluid cohesiveness. In addition, syringe extrusion flow behavior technique was developed as an alternative methodology to measure the cohesiveness of semi-solid and liquid materials. This technique was highly correlated with the perceived cohesiveness from the visual perception and could be used as a standardized methodology of evaluating cohesiveness of semi-solid and liquid materials for industrial purposes.