The Research On Heat Transfer Of Food Analog In High Temperature

The thermophysical properties of solid food is a key verified condition of heat-transfer about fluidization solid foods UHT sterilization,A method using a tiny thermistor as heat transfer model has been developed to measure thermal conductivity of food,and analysis of influence of the calibration ,the medium size and heating power .The results showed that water and glycerin as calibration of the the thermistor have higher accuracy, maximum measurement relative error of thermal conductivity for some standard samples is 5.02%. Thermistor based method applies to the conductivity measurement of food medium.The relative deviation of thermal conductivity for samples is less than 4% by thermistor based method and heat probe method. And further research on the relationship between temperature and thermal conductivity of food, there is a high linear positive correlation between temperature and thermal conductivity of food at the same temperature from 0 to 100℃.The food analog was fabricated by the heat disreversible gels of konjac glucomannan (g-KGM). The g-KGM was proved to fit for the food analog through analysis of its thermophysical properties.The TTIs used in high temperature was composed of markers which embeded in capillary capsule.The mensuration of heat lethal kinetics was carried out for the TTIs,and the Z value is 35.34℃,the Ea value is 63.2 kJ/mol.These data suggested that the TTIs is exactly and applicably.An investigation was carried out for the new food model system. The system was heat treated by overfall heat water.,and the correlative parametes were determined. These parametes also observed by theoretical calculating.The result was agreed with the request of the food model system. The surface heat exchange coefficient hfp were computed by the least absolute lethality difference(LALD) method from experimental center temperature data of g-KGM samples which were acquired by static thermocouple assay during fluidization solid foods UHT sterilization with fluid phase being oil. The computation results of hfp were close to the value predicted, hence the basis of heat transfer theory and the calculation method was advisable.