MODELS FOR THE ELECTRICAL HEATING OF SOLID LIQUID FOOD MIXTURES

To be commercially acceptable, food must be sterile without being overcooked. Volumetric heating of foods using applied electric current (ohmic heating) allows both solid and liquid components of a food to be heated at similar rates, enabling rapid sterilisation. Analytical solutions are only available in very limited cases. The heating of particle liquid mixtures has been modelled using a commercial finite element program, ANSYS. If homogeneous flow is assumed, then a ''unit cell'' of the system can be taken as representative. A two-phase model for the electrical heating and flow of a solid-liquid mixture is derived and discussed. The cooling of electrically heated mixtures is also modelled, and it is shown that the advantages of rapid heating can be lost in cooling without careful design.