Preliminary Study On Cooking Mass Transfer Maturation And Iron Ion Precipitation

The transmission process combined with reaction kinetics and food quality change is considered as the core principle of Chinese cuisine.In the transmission of cooking process,the mass transfer doneness for flavour substances transferring into the food and the transfer of iron dissolving from pots to the food are both transfer processes of substances in the system.So far,study on the doneness of mass transfer in food has been a virgin area,and the problem of iron supplementation in pots is lack of the key section of research.Therefore,it is necessary to study the rule of mass transfer and iron transfer.This paper is to analyze the quality change and mass transfer kinetics of sauce and braised pork,explore the mass transfer doneness of sauce and braised pork by establishing the numerical model and study the migration rule of iron in different materials pots during cooking.The main research contents and results are as follows:1.The quality kinetics of sauce and braised pork during cooking were studied.The results showed that the lightness,redness,shear force,moisture content and salt content followed the first order reaction kinetics,the z-values of which are 47.85°C,45.05°C,37.04°C,52.63°C and 48.31°C,respectively.Therefore,the mass transfer of color,moisture content and salt content in sauce and braised pork can be described by first order kinetics.The kinetic parameters also provide the basic data for promoting the industrialization of sauce and braised pork.2.The mass transfer kinetics of water and salt in sauce and braised pork was studied.The results indicated that the water diffusion coefficient of sauce and braised pork was 0.37 to 0.58×10^-9 m²/s,and the salt diffusion coefficient was 3.77 to 4.51×10^-9 m²/s.The water content and salt content of sauce and braised pork can be described and predicted with Fick's second law,which provides the theoretical basis for enterprise to achieve substance material rate and quality assurance during the cooking process of the sauce and braised pork.3.The preliminary of mass transfer doneness of sauce and braised pork based on the theory of maturity value were studied.The results showed that the mass transfer termination maturity value of sauce and braised pork is measured that IM_T=26.74 min,and the z _M of the sauce and braised pork is calculated as 10°C by the method of coefficient of variation-z _M(CV-z _M)curvature.The heating maturity value for pork loin has been measured that IM_T=0.51 min,which is much less than the mass transfer maturity value in this test,suggesting that the mass transfer doneness of sauce and braised pork lags behind heating doneness.The mass transfer components of sauce and braised pork followed the first order kinetic model,and the maturity value is a function based on the kinetic model,so the maturity value can be used to represent the mass transfer doneness process.The differences between the first and second doneness were analyzed by comparing the standard deviation of termination maturity value at different z-values for sauce and braised pork and stir-fried pork loin.At the same time,the change rule of mass transfer quality factors of sauce and braised pork with different maturity values was analyzed.It was found that there was a good linear relationship between the quality factors and maturity values.The empirical formula could predict a certain quality of food in the cooking process.4.Based on the unsteady heat transfer principle and Fick's second law,a numerical model is constructed to study the transfer characteristics of sauce and braised pork.The simulation results showed that the simulated center time-temperature history of sauce and braised pork was in good agreement with the measured one.In addition,the salt content in the simulated sauce and braised pork was also in line with the measured one.the accuracy and robust properties of the model was verified through the above results.5.A prediction model was established in order to study the migration rule of iron to food acid mimics during cooking process.The results showed that the amount of iron dissolved in the iron pot is about twice as much as that in the stainless steel pot.There was a positive correlation between iron dissolution and temperature and time,while the dissolution of iron in the pot was negatively correlated with the p H value of food under acidic conditions.In addition,different acidic food simulants have different abilities to dissolve iron from pots,since citric acid and lactic acid contain hydroxyl groups,which react with iron in pots to generate complexes that can accelerate the dissolution of iron.Also,according to the iron dissolution concentration model that the cooking time is too long and excessive acidity of food,which may lead to toxic effects from excessive iron intake and long-term consumption will be harmful to human health.In summary,it can be seen that cooking with iron pots increases iron intake and that the iron dissolution in the pot is closely related to the cooking conditions.The prediction model also provides a technical reference for the control of iron dissolving in iron pots.