Simulation And Optimization Studies On The Cooking Process Of Three Common Grains In Sealed Cans

Porridge is a kind of thick paste food,made from some grains including rice,millet or corn,beans etc.Accounting for its soft waxy taste and easy-digestion,it is welcomed popularly by consumers as a traditional Chinese food.Recent years,prepackaged rice porridge have broad market prospect gradually with an increase of variety and production.However,at present,production basically adopt the expansion of traditional ways.Therefore,there is a lack of systematic study on control of product quality and optimization of the cooking process.In this study,the change tendencies of major physical properties of three main components in canned rice porridge(glutinous rice,barley and red bean)were investigated in the duration of canned cooking at different temperatures.These changes were principally analyzed by mathematical model,COMSOL Multiphysics software and Data Trace infinite temperature sensor.The aim is to better describe and quantify the production process of canned rice porridge.The main conclusions in this study were as follows:1.Physical properties including water absorption,softening and shear viscosity of glutinous rice and internal microstructure of starch granules were investigated during the canned cooking process at 100?,115? and 121?.The results showed that hydration rate and softening rate of glutinous,as well as change rate of shear viscosity of cooking liquor all changed with different cooking temperatures and cooking times.But temperature didn't significantly affect the equilibrium value of moisture content(3.99 g· g-1),hardness(0.05 N·N-1)and shear viscosity(6.747 Pa·s).In addition,the change tendencies of moisture content and hardness of kernels could be expressed satisfactorily by Exponential and generalized Exponential models,with relative error lower than 3.650%and 8.604%respectively.Porridge shear viscosity variations were fitted the Sigmoidal and its generalized models,with relative error lower than 8.386%.Thermodynamic properties of the process were also analyzed.The value change of enthalpy change(?H,from-65.01 to-65.19 kJ· mol-1),entropy change(?S,from-0.270 to-0.271 kJ· mol-1· K-1)and free energy change(?G,from 35.7 to 41.4 kJ·mol-1)suggested that the cooking process is thermodynamically favorable and occurred not spontaneously accompanied by exothermic.2?In order to describe and better understand the hydration behaviors of barley grains cooked in a sealed tin can at different temperatures,a three-dimensional(3D)numerical model was developed by COMSOL Multiphysics software and validated to be adequate for representing the volumetric expansion as well as distribution and amount of moisture content.Given that the minute difference between experimental values and simulation values,this model can be applied to the simulation adequately.The performances of the models were determined according to the root mean square error(RMSE,%)and the mean relative deviation modulus(P).In detail,RMSE values were less than 0.068 g·g-1 and P values were less than 5.058%for moisture content simulation,while RMSE values were less than 0.250 g g-1 and P values were less than 5.058%for expansion rate simulation.The rate of hydration and swelling increased evidently with temperature increments,leading to a decrement of about 50%of the time to reach the equilibrium moisture content and volume of barley grains by increasing the cooking temperature from 100 to 121?.However,temperature does not noticeably affect the equilibrium value of the average moisture content.3?In order to model the cooking process of canned adzuki bean porridge at 100?,115? and 121 ?,a two-dimensional axisymmetric model was developed by COMSOL Multiphysics software,and the model was adequate for representing the heat transfer,mass transfer and large deformation.The research shows that the simulated value is close to the experimental value,and RMSE values were less than 0.086 g· g-1 and P values were less than 5.851%for moisture content simulation,while RMSE values were less than 0.456 g ·g-1 and P values were less than 9.112%for expansion rate simulation.The rate of hydration and swelling increased evidently with temperature increments,leading to a decrement of about 39.7%of the time to reach the equilibrium moisture content and volume of barley grains by increasing the cooking temperature from 100 to 121 ?.Moreover,temperature increments noticeably increased the equilibrium value of the average moisture content.