Relationship between Number of Chewing Cycles and Fragment Size of Agar Gels

Using 4 g samples of 15 mm and 3.5 mm agar gel cubes, the size of gel pieces generated after mastication (1 similar to 10 times) was measured. The total number of gel pieces, which were arranged in size from large to small, was then categorized into 10 groups, and the average size in each group was calculated. Next, the correlation between the mean size of gel pieces and the number of chewing cycles was investigated. In the 15 mm agar gel cube group, the size of gel pieces after mastication was widely distributed, and the gel bolus was evaluated to be more easily collected than the bolus of the 3.5 mm agar gel cubes. In the 3.5 mm agar gel cube group, the size distribution of gels after a small number of chewing cycles resembled a normal distribution; however, the size distribution of the 3.5 mm agar gel cubes approached that of the 15 mm agar gel cubes with a larger number of chewing cycles. With respect to the rate of reduction of the average size for the number of chewing cycles in all 15 mm cubic agar gel groups and in the 3.5 mm cubic agar gel groups with small size pieces, it was accepted that crossover structure, i.e., two kinds of domains where inclination differs, exists. The present results using 4 g samples of both 15 mm and 3.5 mm agar gel cubes suggested that facile bolus formation, an important factor in swallowing, is influenced by the size dispersion more than by the actual size of gel pieces that comprise the bolus. Furthermore, the results also suggest that the gel bolus is easier to gather with gel pieces of various sizes than with those of similar sizes.