Abstract
To study which physical properties of bolus trigger swallowing during cooked rice mastication, we measured the texture of bolus collected from the oral cavity immediately prior to swallowing by texture profile analysis. Ten healthy adult participants masticated three types of cooked rice samples mixed with 10, 20, or 30 wt % rice starch paste (R+ 10% RP, R+ 20% RP, R +30% RP). R+30% RP was the most adhesive in the three. The number of chewing strokes until swallowing was significantly higher during mastication of R +30% RP than R +10% RP and R+20% RP. Hardness of the R+ 30% RP bolus was significantly lower than that of the R +10% RP and the R+ 20% RP boluses. On the other hand, the difference in both adhesiveness and cohesiveness of bolus was not significant. The mean value of the particle size in a bolus immediately collected prior to swallowing during mastication of lower adhesive cooked rice was significantly larger than that in the bolus during mastication of normal cooked rice.
These results suggest that adhesiveness of the cooked rice bolus may relate to the swallowing threshold, and also suggested that the particle size in the bolus may not concern the occurrence of swallowing during mastication of cooked rice.
