Abstract
Although saliva has an important role enabling food to be chewed smoothly, there are few studies of the effect of the saliva flow rate on the chewing food. The aim of this study was to evaluate the saliva volume secreted and the change of the water contents of the food bolus when food is chewed.
The water content of the food bolus at time of 1/3,2/3,1 and 4/3 from the chewing start to swallowing was examined in 8 adults. The foods selected were biscuit(water content: 3%), sponge cake (26.9%), hot cake (40%), rice (60%), corn (70%), apple (85.8%).
The percent of the water content of the food bolus in the same subjectsshowed a constant value with a low standard deviation. The mean salivary volume secreted by one mouthful of food was highest with biscuit, and this was inversely related to the initial water content of the food. The increasing rate of the water content of the food bolus was highest at time of 1/3 from the chewing start to swallow, and after then this rate showed fixed changes.
These results suggests that the initial water content of food is an important factor regarding the salivary flow and having the food bolus swallowed in chewing.
