Comparison of Two Tests Used for the Classification of Food Thickeners in the Management of Dysphagia.

Dysphagia is the medical term used to describe swallowing problems resulting from a disorder in the mechanics of swallowing. Many disorders that can cause dysphagia are associated with the elderly and, with the continuing demographic shift, dysphagia is a growing problem. There seems to be little doubt among health professionals that thicker foods are easier and safer to swallow than thinner foods, however, the problem remains of how do you define thick. Rheological properties of thickening agents vary considerably. Starch has been widely used in instant thickening products for dysphagia, but more recently guar gum – and in particular xanthan gum – is becoming increasingly popular. The rheological properties of the bolus significantly influence the swallowing process, and the use of hydrocolloids to control the rheology can greatly help in the management of the condition. In this study five commercial products for dysphagia containing different hydrocolloids have been tested according to Japanese proposals for classifying thickness of products for dysphagia (Toromi), based on viscosity at 50s⁻¹ and the Line Spread Test (LST). Viscosity was measured at 50s⁻¹ as a function of concentration and compared to the LST results measured over the same concentration range. The results have been compared and discussed in terms of the rheological properties of the different thickeners used in the products.