Research On Oral Processing Ability Of The Elderly And Chewing Behavior And Subjective Evaluation Of Different Textures Of Food

Population aging has become a global social phenomenon.With the gradual deterioration of physiological functions of the elderly,the problem of eating difficulty/disorder has become increasingly prominent,severely affecting the physical and mental health of the elderly."Eating Capability"can be used to comprehensively describe the differences in individuals’abilities,among which oral processing ability is emphasized,mainly including bite force,tongue strength,salivary secretion,masticatory function,etc.This study aims to establish a scientific method for evaluating oral processing capability,to clarify the critical indicators（bite force,tongue pressure,lip pressure,saliva flow rate）from two aspects of oral physiological characteristics and masticatory performance,and to design a portable eating capability tester.Furthermore,an applicable masticatory performance test method for the elderly was established.Further,combined with the sensory evaluation of different textural foods,the correlation between oral processing ability,food texture properties and sensory perception was investigated to provide ideas for the textural design of special foods for the elderly.The main results and conclusions are as follows:（1）A portable eating capability testing device was designed to evaluate the oral physiology of the elderly effectively,including four components:bite force,tongue pressure,lip pressure,and saliva flow rate.The signals generated based on the sensors were converted into digital signals for output by the master control module.The bite function module found that the resistance tends to change linearly with the load force,and the full-scale error is less than 3%;the tongue/lip pressure function module found that the accuracy is within±2 k Pa,and the coefficient of variation is less than 0.5%with high repeatability.The feasibility of the device was further verified by comparative analysis of the current method and the new device for measuring bite force,tongue,and lip pressure in 10 volunteers respectively.（2）The glucose concentration of gelatin particles during mastication was measured by a glucose meter and compared with the optical scanning method to explore the feasibility of evaluating the masticatory performance of different individuals.The results show that:a significant linear relationship existed between the five standard glucose solutions and glucose meter test results（glucose meter:R²=0.9989）,indicating the high accuracy of the glucose meter.With the increase of mastication,glucose concentration showed a significant positive correlation with a broken area（r=0.893,p<0.01）and a significant negative correlation with median size X₅₀（r=-0.933,p<0.01）.Therefore,this newly established masticatory performance test method is feasible and highly effective.In addition,the masticatory efficiency values showed a significant negative correlation with glucose concentration,verifying the method’s reliability.A significantly positive correlation between glucose concentration and occlusal force in young and older adults（the youth:r=0.874,p<0.01;the elderly:r=0.638,p<0.01）suggests masticatory performance in the elderly can be detected by the glucose release method.（3）A video recording method was used to observe the chewing behavior of individuals while a subjective evaluation was performed.The effects of oral processing ability on chewing behavior and sensory perception of the texture of different foods were explored in the elderly.The results show that:Bite force was significantly positively correlated with masticatory performance（r=0.913,p<0.01）,and the tongue and lip pressure were moderately positively correlated with masticatory performance（tongue pressure:r=0.498,p<0.05;lip pressure:r=0.503,p<0.05）.Through multiple linear regression analysis,it was found that the changes in masticatory performance of the elderly were mainly caused by the bite force.Oral physiology and masticatory performance can influence individual chewing behavior for different foods.Besides,the qualitative properties of the food significantly affect the chewing behavior of the elderly.During the subjective evaluation,there was a significant relationship between the individual’s chewing behavior and the difficulty of oral food processing（chewing cycle:r=0.535,p<0.01;chewing time:r=0.556,p<0.01）.Furthermore,this relationship is generated by the different dominance by bite force.