The effect of oral processing on the viscosity of thickened drinks for patients with dysphagia

Objective
To determine whether a gum-containing thickener maintains its viscosity better during oral processing than a completely starch-based thickener.
Methods
Thirty-five healthy volunteers participated in a double-blind, cross-over study. Artificial tap water was thickened to honey-like consistency (effective viscosity of 1,300±100 mPa·s at a shear rate of 50 per second at 20℃) with a starch-based thickener (SB) or a gum-containing thickener (GC). Bolus viscosity was determined after standardized oral processing of the thickened water by the subjects for 10 and 20 seconds. Significant effects were determined by ANOVA analysis and pairwise comparisons.
Results
Both thickeners were susceptible to breakdown during oral processing. However, GC-thickened water retained its viscosity significantly better than SB-thickened water.
Conclusion
The presence of gums has a protective effect on the starch hydrolysis by salivary amylase in thickened drinks, which may facilitate safer swallowing.