Globalization And Application Of Numerical Simulation Of Cooking Process

Chinese stir-frying is one of the most distinctive and widely used cooking method.Due to the characteristics of considerably unsteady state and high-temperature and short-time treatment,traditional analysis methods,such as orthogonal test,the response surface model and so on,can't conduct global analysis on heat and mass transfer mechanism,which gave rise to difficultly obtain global time-temperature history of particles.However,the time-temperature history played a fundamental role on dynamic calculation and process optimization.Therefore,the only way to study the heat transfer process of food particles during Chinese stir-frying is via the numerical simulation.The previous model of Chinese cuisine was constructed in premise of ignorance of oil temperature changes and multi-particle properties of food,which was the key parameter to ensure the mathematical model did not deviate from truth.To study the mechanism of heat and mass transportation,as well as the changes in maturity and quality of food particles during the Chinese stir-frying process,a global heat and mass transfer model including multiphase coupling phase transition was developed to simulate the global changes of temperature and components,at the same time by combining the pre-built model of heat and mass transfer in porous media considering shrinkage with the oil temperature and heat balance equation of the whole food system,which was constructed on the basis of Fourier's law,Darcy's law and the law of energy conservation.The new model has five governing equations,two shrinkage formulation,eight boundary conditions,ten early conditions,29 additional equations,and 52 associated parameters,and the solution technique was developed by means of COMSOL Multiphysics 5.4.Numerical simulation of stir-frying process of pork tenderloin was carried by means of the developed global mathematical model of heat and mass transfer to obtain the history of oil temperature changes,temperature distribution and water content distribution of pork tenderloin during stir-frying process.Firstly,the measured oil temperature history was smoothed by means of MATLAB.Then the difference between the simulated oil temperature curve and the determined oil temperature curve was verified to be in good agreement by the method of LSTD and correlation coefficient.The simulated center time-temperature history of pork tenderloin was verified to be in accord with the real center time-temperature history during stir-frying process by means of TTIs(Time Temperature Integrator).The results showed that the maximum error between the calculated enzyme activity and the measured enzyme activity was 3.12%in the case of different initial heating oil temperature and different oil ratio,which met with the calculation requirements of cooking technology.On this basis,according to the uniqueness theorem of mathematical solution,the simulated center time-temperature history of pork is consistent with the measured one.Lastly,the moisture content of the Chinese stir-fried pork tenderloin was used as comparation to validate the model accuracy in the case of different heating oil temperature,oil ratio and heating power,the absolute error of which were 0.0110,0.0144 and 0.0061 respectively.The results indicated that the accuracy and robust properties of this model was greatly increased after considering the global process.The effects of initial heating oil temperature,heating power,and oil ratio on pork quality were simulated using the validated global mathematical model of heat and mass transfer based on the kinetic principle.The initial heating oil temperature of fried pork was simulated and optimized by taking the minimum volume average overheated value(O_v)of water content,the highest volume average retention rate(Q/Q_0avg)of vitamin B₁retention rate and the minimum surface over-heated value(O_s)of surface color as objective condition,and the terminal maturity value of pork as restrictive condition.The optimal initial heating oil temperature was 100?.Moreover,the effects of heating power and oil ratio on the quality of cooked pork were simulated.The results showed that the higher heating power and oil ratio,the better cooking quality.The rationality of cooking optimization principle and maturity value theory is proved.