Relationship between Physical Properties of a Food Bolus and the Swallowing Threshold during Mastication of Gel Type Food.

Abstract

To study which physical properties of a food bolus trigger swallowing during mastication of gelatinous food, we measured the texture of a bolus immediately prior to swallowing by texture profileanalysis. Filter paper soaked in 0.2M tartaric acid (acid stimulation) or distilled water (DW stimulation) was placed on the dorsal surface of the tongue of 10 healthy adult participants for 1 minute before they masticated rice cake (RC) or gummy candy (G). The G bolus was significantly (p<0.05) harder immediately prior to swallowing after acid stimulation than after DW stimulatien. On the other hand, hardness, adhesive. ness and cohesiveness of the RC bolus did not differ significantly between the two masticatory conditions (after acid stimulation and DW stimulation). After DW stimulation, the texture of the RC bolus during the middle stage of mastication was compared with that just before swallowing. The RC bolus at the middle stage was significantly harder (p<0.001) and more adhesive (p<0.05) than just before swallowing. These results suggest that the degree of adhesiveness of a bolus might be closely related to the swallowing threshold for gelatinous food such as rice cakes.