2017 Volume 64 Issue 3 Pages 123-131
The hardness (a parameter obtained from texture profile analysis) and viscosity of thickener solutions with different flow properties (viscosity (μ) vs. shear rate (γ̇)) were measured for care foods for dysphagic patients. In addition, the correlation between hardness and velocity of food through the pharynx was investigated. Carboxymethyl cellulose (CMC) and locust bean gum solutions were almost considered Newtonian fluids, while solutions of xanthan gum and commercial thickening powder showed similar shear thinning. Plots of μ at a shear rate of 3 s-1 vs. hardness were well fitted with a straight line. However, plots of μ at a shear rate of 25 s-1 and 50 s-1vs. hardness could be fitted with two different straight lines for solutions with different flow properties. As the values of hardness and viscosity increased, a decrease was observed in the maximum velocity through the pharynx, Vmax, which has been reported to be a good predictor of aspiration risk. These results confirm that the flow properties of solutions should be considered when substituting hardness for viscosity as an index for care food for dysphagic patients.
