Construction And Feasibility Test Of A New Multifunctional Mastication Simulator

Food oral processing is a highly complex and dynamic process that involves the continuous co-operation of multiple organs and body structures.However,due to ethical constraints and the difficult access of the oral cavity,it is technically challenging to directly observe the changes in the physicochemical properties of food and the way multiple organs work together during the relevant processes.To overcome the above technical difficulties related to oral processing and sensory perception of food,a new multifunctional mastication simulator was developed and its feasibility was tested in this study.This device is expected to provide evidence-based reference and new ideas for human sensory intensity perception of taste（salty and sour）,aroma,and food texture in oral processing,and to provide new references for solving the problem of difficult visual observation of changes in physicochemical properties of food masses in oral processing.The specific research contents and conclusions are as follows.（1）The construction process of the new multi-functional mastication device is introduced in detail from the functional and structural aspects,and the mechanical structure and software control parts of the static oral structure simulation,dynamic mastication,and sensor sensing of the device are analyzed in detail.After the completion of the device construction,no-load operation and fatigue test have been conducted to verify the feasibility of the mechanical structure and software control of the device.At the same time,structural and accessory adjustments were made to improve mixing efficiency of the saliva receiving tray,heating efficiency in the mastication chamber,and sample crushing efficiency.Finally,practical experimental operation instructions for the device were obtained,along with the range of parameters that can be entered into the device and the useful information that can be obtained from each data collection end of the device based on the experimental operation procedure.（2）In order to test the reliability of the device,five separate tests were designed:the difference in crushing ability of the device at different speed（to construct an exclusive crushing ability classification criterion）,the degree of anthropomorphism of the sample crushing ability,the reliability of p H and conductivity sensors to monitor in real time and in sample differentiation,the ability to collect and analyze specific aroma substances in combination with an electronic nose,and the recover rate of the samples before and after the experiment.Results showed:the device was capable of giving different fragmentation effects on the same standard gel samples different set speeds（the corresponding mastication times were plotted against the total area of the fragmented gel）.The fitted R² of the curves reached 0.8989,0.9591,0.9995,0.9463,0.9596,0.9926,0.9839,0.9608,0.888 when the velocity parameters were set to 4,6,8,10,12,14,16,18 and 20 mm/s,respectively,confirming its ability in establishing exclusive differentiation criteria for samples.The device was able to reproduce to some extent the crushing of nut samples during the oral processing of volunteers(no significant difference between the median particle size(X₅₀)of the crushed food masses inside and outside the body at the corresponding number of chewing sessions).The device was capable of real-time monitoring p H and conductivity of different samples during simulated mastication（plotting correlation curves of p H and conductivity over time）,and was able to differentiate different samples from the curves.The device was able to temporarily retain the aroma substances released from the samples during the crushing process,and the connection between the electronic nose and the device was established using a syringe and an aluminum air collection bag,based on to obtained curve of the intensity of the aroma substances as a function of time.The weight analysis of the samples before and after crushing confirmed satisfactory recovery of the food samples compared with the in situ experiments.（3）Same standard samples were tested both in vitro and in situ by monitoring:the median particle size of the food bolus after sample crushing（corresponding to volunteers’perception of sample fragility）,p H（corresponding to the volunteer’s perception of sourness during sample chewing）,conductivity（corresponding to the volunteer’s perception of saltiness during sample chewing）and value of the crushing force applied to the sample by the device（corresponding to the volunteer’s perception of hardness of the sample）during the crushing process of the standard sample,and the monitoring of the dynamic release of aroma during the crushing process of the sample containing aroma components（corresponding to the volunteer’s perception of aroma during sample chewing）.And carry out regression analysis between relevant parameters,the R²of the correlation curves were 0.9723,0.9912,0.8671,0.9957,and 0.8405,respectively,which can initially establish a link between the results of the device and sensory experiments.（4）In vitro simulated chewing experiments were conducted using six different brands of commercially available peanut samples.The median particle size of the food bolus after peanut crushing,the real-time changes in electrical conductivity during sample crushing,the magnitude of crushing force applied to the samples by the device and the dynamic release of aroma components during the crushing process were obtained and monitored.Volunteer sensory experiments were also conducted to confirm that the device was also able to provide sensory data for real samples in terms of salinity,crispness,hardness and aroma release intensity for preliminary comparison of samples on various attributes.In this study,the newly developed multifunctional mastication simulator was described in detail and the feasibility of each function was tested using standard samples and real foods.Results confirmed that the newly mastication simulator could be used as a valid in vitro technique to simulate oral processing of food.