Modeling of thermal conductivity of granular starches (original) (raw)

Prediction of the flective thermal condzctivity of granular and porous foods is essential in engineering calcul&ons and in modeling of food processes. Structural models are more useful than empirical equations, since they are based on the physical and transport properties of the components of the food system. Six structural (geometric) models were tested, using experimental data on the eflective thermal conductivity of granullar starches in the ranges of bulk density 500-800 kg/m', moisture content O-@4 kg water/kg dry solids and temperahue 25'-70"C. The parallel model of heat conduction in the granular starch (solidJgas phases) and in the starch granules (dry starch/sorbed water phases) yielded the lowest standard deviation between the experimental and the predicted values of thermal conductivity. Combinations of the parallel and the Maxwell models yielded acceptable results. *New Jersey g A ricultural Experiment Station publication No. D-10544-2-89.