Abstract
The mode of mastication of foods was examined through visual analysis with videofluorography, using agar and gelatin jellies as test foods. The mode altered from compression with the tongue and hard palate to shearing with the dentition as the hardness of jelly was increased. The thresh-olds of hardness requiring a shift of mastication mode from compression to shearing were 0.08 kg for the agar jelly and 0.03 kg for the gelatin jelly, although the gelatin jelly shear strain was larger. Rupture stress was also found to be an important factor in changing the mode. Visual analysis of videofluorography revealed that the food texture may be recognize by initial compression between the tongue and hard palate, around the incisive papilla. Very soft food was treated in the some way as liquid food. The mastication mode of a food may be determined according to the texture. The food was mastication either by compression with the tongue and hard palate or by shearing with the dentition. It was suspected that the process of initial compression of food with the tongue and the incisive papilla region is the first step of texture recognition.
