73C-15 |
Simulation and optimization of pasteurization processes in plate heat exchangers of fruit juices and beverages |
J. S. WELTI-CHANES1, A. L. Ruíz-Medina, F. Laserna-Figueroa, and J. L. Ramírez-Juárez. (1) Chemical and Food Engineering Department, Universidad de las Américas-Puebla, Santa Catarina Mártir, Puebla, 72820, Mexico Thermal treatments in heat exchangers of juices, nectars and other fruit beverages at industrial level, are usually based on specifications given by equipment suppliers rather than on the theoretical concepts on which destruction of microorganisms and thermal deterioration of products are based. Hence, the process conditions applied at industry are excessive, generating products adequately sterile but with a great thermal damage besides an excessive use of energy during the process. The objective of this work was to generate a computational program that simulates the thermal processes industrially applied to 9 different fruit products (pH < 4.0), relating them to the sterility levels and thermal damage that can be reached. Program’s results were compared with those recorded at industrial level, what allowed to take decisions to optimize the process. The computational program developed in Delphi ver. 4, analyzes the pasteurization processes in plate heat exchangers of fruit drinks (cold or hot packaging), and operates in computers with Windows 95/98 or Windows NT4. It consists of five modules: configuration, microbiology, calculation of thermal processes, process simulation, and optimization. The sterility levels (F values) achieved in each case were determined using the product’s flow conditions and temperature profiles, and the general method. It was demonstrated, for all cases, that the F value achieved was 2 to 5 times higher than the required one. This information together with data of development of cooked flavor in the product and process’ costs, permitted simulation and generation of optimum process conditions to assure the product’s sterility and to minimize its deterioration and the process’ costs. The results obtained demonstrated that it is feasible to employ the theoretical basis of treatment of fluid foods in plate heat exchangers and computational aid for a better understanding of these industrial processes and their optimization in terms of quality and costs.
Session 73C, Food Engineering: Transport Processes and Kinetics
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