NONLINEAR CONSTRAINED OPTIMIZATION OF THERMAL PROCESSING: I. DEVELOPMENT OF A MODIFIED ALGORITHM OF COMPLEX METHOD

Abstract

ABSTRACTThe complex method, a general and flexible optimization algorithm, was used to determine the optimum process temperature profiles during thermal processing to maximize (optimize) the objective function of volume average retention of thiamine in conduction heated foods with restrictive explicit and implicit constraints. Implicit constraints were the target lethality at the coldest point, and a threshold below which the center temperature must reach at the end of the process. A process temperature range of 5–150C was used as an explicit constraint. Another explicit constraint was that the process temperature had to reach 5C at the end of the process. Control variable for the optimization was process temperature profile discretized at equidistant time steps throughout the process. All calculations were performed using a computer program written in Microsoft Visual Basic V. 6.0. This Windows‐based software calculated the optimum temperature profiles with resulting objective functions and implicit constraints. The developed algorithm for the Complex Method was found to be satisfactorily usable for the optimization of thermal processing of conduction heated foods.