73C-19 |
Optimization of double-sided cooking of meat patties using integrated controlled random search for dynamic systems (ICRS/DS) |
S. E. ZORRILLA1, J. R. Banga, and R. P. Singh. (1) Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 Dynamic optimization techniques can be used to find the best operating policies for hamburger patty cooking. Double-sided contact is one of the commonly used methods for cooking hamburgers. In this case, plate temperature, gap thickness between plates and cooking time are the control variables. The product must be cooked to certain temperatures and/or for certain period of time to avoid problems of contamination with Escherichia coli O157:H7. However, an overcooked product presents poor quality characteristics. Our objective was to design optimized thermal processes for the cooking of hamburger patties by double-sided contact using a dynamic optimization technique. The mathematical statement was to find the optimal control (heating surface temperature) over cooking time to minimize (or maximize) the performance index (cooking or textural parameters). The control vector parameterization framework was applied. Therefore, the original infinite dimensional optimization problem was transformed into a non-linear problem using a suitable control parameterization scheme. A stochastic algorithm was used to locate the global optimum with reasonable computation effort (Integrated Controlled Random Search for Dynamic Systems). The temperature of both plates was considered as one control variable. The constant plate temperature for each case that ensures the desired center temperature and lethality, and minimizes the performance index (cooking loss) was considered as the nominal case. The performance index improved when two control elements of variable size were used (approximately 8% compared to the nominal case), but no improvements were noted when more than two control elements were considered. When the lower bound was relaxed and two control elements were used, the performance index improved significantly (18% compared to the nominal case). The application of adequate dynamic optimization techniques can lead to improved specifications and new developments in the design of equipment and sensors that ensure improved safety and quality of cooked patties.
Session 73C, Food Engineering: Transport Processes and Kinetics
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