Abstract
To clarify the changes in physical properties of a bolus during mastication of cooked rice, we measured the texture of bolus collected from the oral cavity at three different stages of cooked rice mastication: M stage, the halfway of mastication; L stage, immediately prior to first swallowing; and +20% stage, the number of chewing strokes 20% beyond a point at which the first swallowing would usually occur. Eight healthy adult participants masticated cooked rice sample (6g). The texture of the bolus was measured by texture profile analysis. Hardness of the bolus decreased significantly (p <0.05) from the M to L stage. This result suggests that the decrease in hardness of a bolus may be a necessary factor for the initiation of swallowing. Adhesiveness of the bolus decreased significantly (p <0.01) from the M to the +20% stage. On the other hand, cohesiveness of the bolus unchanged during mastication. These result suggest that the swallowing of cooked rice bolus may be triggered when adhesiveness of the bolus is reduced to meet the swallowing threshold.
