Physical and textural properties of foods with swallowing ease for aged people

Abstract

The physical properties of foods related to mastication and swallowing are explained. The maximum velocity, V_max, obtained by the ultrasonic pulse Doppler method, and the time required for the bolus to flow in the pharynx, t₂>, obtained by acoustic swallowing sound, are considered to be good predictors of aspiration risk. For thickener solutions, the viscosity, µ, especially that measured at a shear rate of 20–30 s⁻¹ and above, can be a suitable index for liquid-type care foods for people with difficulties in swallowing. The ‘hardness’ is considered to be the most suitable index for semi-solid care foods among the parameters obtained by texture profile analysis (TPA). The V_max and t₂> can be interpreted as “cohesiveness (i.e., ease to form bolus)” of food from the viewpoint of the flow velocity distribution in the pharynx. On the other hand, ‘cohesiveness’ obtained by TPA does not reflect the ease of forming a bolus of food.