BIOLOGICAL VALIDATION OF MATHEMATICAL-MODELING OF THE THERMAL-PROCESSING OF PARTICULATE FOODS - THE INFLUENCE OF HEAT-TRANSFER COEFFICIENT DETERMINATION

This paper describes a mathematical procedure to determine the lethali ty in a continuous sterilization system for foods containing large par ticles. A computer program to predict the temperature distribution wit hin the flowing particles and heat lethality was developed using finit e difference equations. The convective heat transfer coefficient betwe en fluid and particles was experimentally estimated by means of a mode l system consisting of an immobile potato cube surrounded by a continu ously flowing fluid. To verify this approach, a tubular heating-holdin g pilot plant was used for processing potato cubes in a NaCl solution. A biological validation of the mathematical model was carried out by inoculating the potato cubes with yeast cells and comparing the experi mentally measured lethality values with those calculated using the com puter program. Quite a good agreement was obtained between the model p redictions and the experimental findings.