Sensory perception and flow properties of dysphagia thickening formulas with different composition

Among the hydrocolloids used as thickeners for dysphagia, xanthan gum has gained importance in the last years. This work studies the sensorial perceived differences and flow behavior between ascending concentrations for both, a gum-based commercial thickener and a traditional starch-based product. Sensorial discriminant analysis was performed by a panel of untrained assessors (1:3 men to women ratio and 1:1 < 50 years and > 50 years). The accuracy of the panel and the possible effects of age or gender were monitored. The physical properties of both thickeners were studied by a syringe flow test, at 0, 10 and 30 min from mixing. The panel probed to be repetitive and reproducible and no significant effect of gender or age was detected. In general, it was possible to discriminate significantly among concentrations half-narrower than those usually proposed by commercial brands. For both products, it became more difficult to discriminate between consistency changes at the higher concentrations. Panelists ranked the ascending concentrations unevenly, with a linear trend for the lowest concentrations, which also showed wider relative perceived distances. Thickening formulas behave differently in the syringe flow test. Starch-based thickener showed in general higher values than expected, while lowest categories (thin and slightly thick) were difficult to achieve. The gum-based thickener had a more gradual behavior. Time from mixing affects the flow test results. In conclusion, starch- and gum-based thickeners cannot be used as equivalent products. Taking into account both discriminant capacity and preparation variables, such as time from mixing, lower product amounts could possibly be prescribed to achieve adequate consistencies for dysphagia treatment.