Texture Analysis of Food Samples Used for the Evaluation of Masticatory Function

Introduction Food questionnaire surveys are often used to evaluate masticatory function. In daily clinical practice in Japan, a survey is performed using a list of food groups suitable for the Japanese diet. The foods on the list were categorized into five food groups based on their mastication index. The patient's masticatory function is determined by the food groups that can be eaten. The masticatory index, which indicates chewability, was defined based on the percentage of 110 denture wearers who responded that they could eat food normally. A survey with this list is useful because of its simplicity; however, there is a lack of objective data on the physical properties of food samples. Consequently, to make the results of the food questionnaire survey more objective indicators, we performed a texture analysis of the food samples on the list. Methods We performed a texture analysis of 93 samples from 77 food items on the list. Compression tests were performed using a texture analyzer, and hardness, cohesiveness, adhesiveness, viscosity, and gumminess were calculated by a texture profile analysis. Results Even with the same ingredients, the results differed depending on the presence or absence of food skin, the direction of pressing (vertical or horizontal), cooking methods, and temperature differences. However, the masticatory index was negatively correlated with hardness (-0.4157, p<0.001) and gumminess which is determined as the product of hardness×cohesiveness (-0.4980, p<0.001). Conclusion This study suggests that the masticatory index indicating chewability may be related to the hardness and cohesiveness of food samples. Even for foods with the same hardness, the degree of difficulty in forming a food mass is expected to vary depending on differences in cohesiveness. Moreover, the presence or absence of food skin, the direction of food fibers, cooking methods, and temperature differences change the physical properties of the food. Therefore, the composition and structure of the foods or eating habits of patients should be taken into consideration when conducting a food questionnaire survey.