Swallowing Characteristics and Tongue Surface Movements of Human with regard to Pasty Foods

―Effects of Temperature and Physical properties―

Abstract

The effects of temperature and physical properties of pasty food on the swallowing characteristics and tongue surface movements of human subjects were evaluated in this study．Two kinds of pasty food were used as samples： sweet potato containing butter and carrot with an added commercial thickening agent．Physical properties (hardness and yield stress)，swallowing characteristics， and tongue surface movements were investigated at 10℃，25℃ and 50℃．Swallowing characteristics were evaluated by Scheffe's paired comparison．Swallowing frequencies were also evaluated．In ultrasound analysis of tongue movement during swallowing，the grooving depth，grooving duration and grooving width of the tongue during swallowing of samples were evaluated．The following results were obtained．

The hardness and yield stress of both samples became lower with increase in temperature．ln particular，sweet potato containing butter had signficant temperature dependence．ln sweet potato samples，the smoothness and ease of swallowing of 50℃ samples were better than those of 10℃ or 25℃ samples．ln carrot samples，the palatability of 10℃ samples was better than that of 25℃ or 50℃ samples；however，in sweet potato samples， the palatability of 50℃ samples was better than that of 10℃ or 25℃ samples． With increase in temperature， the swallowing frequencies became higher for carrot，but lower for sweet potato． The mean value of grooving depth of tongue surface movements during swallowing of sweet potato at 50℃ significantly increased compared to the value at 10℃．