Abstract
We previously reported the effect of the physical properties of different staple foods on masticatory behavior during the course of eating of restored school lunches. The purpose of the present experimental study was to examine whether the difference in the main dish affected masticatory parameters while eating entire school lunch and while eating the food separately.
We prepared three types of the school lunches on the ba sis of the menus of the 1950's in our previous study. As the food which differed among each lunch, we selected fried meat, potato croquette and deep-fried fish, and confirmed that their hardness were significantly different from each other for measuring using texture profile analysis. Fried meat was the hardest followed by deep-fried fish and potato croquette in that order. Nine healthy adult subjects (3 male and 6 female) ate three school lunches on separate days. The total masticatory strokes, the total masticatory time and the total number of ingestion while eating each lunch were calculated using recorded videotapes. The total masticatory strokes, the total masticatory time and the total number of ingestion were nearly the same among the three lunches in terms of mean value for all of the subjects, whereas the total number of ingestion in females was greater than that in males. The total masticatory strokes in females were, therefore, greater than that in males, while the total masticatory time in females was longer.
When the same subjects ate three types of main dish separately, the w eight of one mouthful, the masticatory strokes per mouthful and the masticatory time per mouthful were calculated. With respect to the weight of one mouthful, croquette was the largest among the three foods. The mean weight of one mouthful in males was greater than that in females for all of the food. The masticatory strokes per mouthful and the masticatory time per mouthful, however, did not differ among the three types of food and between males and females.
These results suggested tha t, on ingestion of different foods, the weight of one mouthful was regulated according to each food as the masticatory strokes and the masticatory time per mouthful became approximately constant. This regulation is likely to be performed by the brain on the basis of previous experiences and memories in the anticipatory stage before ingestion of the food.
