Global optimization of process conditions in batch thermal sterilization of food

Abstract Conventionally, food is significantly over-processed to ensure safety. Dynamic optimization can be used to compute optimal thermal operation condition to ensure maximum product quality while assuring food safety. Local optimization (LO) algorithms have been used to compute optimal profiles. However, LO is not guaranteed to find the best solution for non-convex functions. We show that the problem can be formulated as a convex problem with a reverse convex constraint and we implement Tuy’s algorithm to optimize globally. The method is deterministic and guaranteed to find the global optimum and therefore it is suitable to evaluate the effectiveness of local optimization to compute global optima. We compared the results of LO and global optimization (GO) to find that GO gives significantly better results for two and three heating time periods. However, for four periods the local optimizer catches up. This suggests that LO is good enough for this problem if we consider strategies with more than four periods implementable. However for many commercial processes less than four heating–cooling stages are used.

[1]  Gintautas Dzemyda,et al.  Stochastic and global optimization , 2002 .

[2]  Fabio Schoen,et al.  Stochastic techniques for global optimization: A survey of recent advances , 1991, J. Glob. Optim..

[3]  Peter Richards,et al.  Numerical simulation of natural convection heating of canned food by computational fluid dynamics , 1999 .

[4]  Julio R. Banga,et al.  Global Optimization of Chemical Processes using Stochastic Algorithms , 1996 .

[5]  Israel Saguy,et al.  OPTIMAL RETORT TEMPERATURE PROFILE IN OPTIMIZING THIAMIN RETENTION IN CONDUCTION-TYPE HEATING OF CANNED FOODS , 1979 .

[6]  Eva Balsa-Canto,et al.  A novel, efficient and reliable method for thermal process design and optimization. Part I: Theory , 2002 .

[7]  Lothar Leistner,et al.  Food preservation by hurdle technology , 1995 .

[8]  S. Holdsworth,et al.  Optimisation of Thermal Processing - A Review , 1985 .

[9]  A. Mujumdar,et al.  Handbook of Food and Bioprocess Modeling Techniques , 2006 .

[10]  H. Tuy.  Convex programs with an additional reverse convex constraint , 1987 .

[11]  Peter J. Fryer,et al.  Heat transfer in food processing: ensuring product quality and safety , 2005 .

[12]  Chantal Smout,et al.  Modelling temperature variability in batch retorts and its impact on lethality distribution , 2000 .

[13]  Peter J. Fryer,et al.  Product/Process integration in food manufacture: Engineering sustained health , 2006 .

[14]  Cristina L. M. Silva,et al.  Modelling optimum processing conditions for the sterilization of prepackaged foods , 1993 .

[15]  C. McFarlane,et al.  Visualization and Modelling of the Thermal Inactivation of Bacteria in a Model Food , 1999, Applied and Environmental Microbiology.

[16]  P. Richardson,et al.  Thermal Technologies in Food Processing , 2001 .

[17]  Christodoulos A. Floudas,et al.  Deterministic global optimization - theory, methods and applications , 2010, Nonconvex optimization and its applications.

[18]  Lino J. Alvarez-Vázquez,et al.  Modelling and control of natural convection in canned foods , 1999 .

[19]  Peter J. Fryer,et al.  Optimising the quality of safe food: Computational modelling of a continuous sterilisation process , 1999 .

[20]  Nguyen V. Thoai,et al.  Concave minimization via conical partitions and polyhedral outer approximation , 1991, Math. Program..

[21]  G. S. Tucker.  Development and use of numerical techniques for improved thermal process calculations and control , 1991 .

[22]  Julio R. Banga,et al.  Optimization of the Thermal Processing of Conduction-Heated Canned Foods: Study of Several Objective Functions , 1991 .

[23]  Eva Balsa-Canto,et al.  Computing optimal operating policies for the food industry , 2006 .

[24]  P. Fryer,et al.  7 – Modelling particular thermal technologies , 2001 .

[25]  P. Richardson,et al.  Improving the thermal processing of foods. , 2004 .

[26]  John P. Norback,et al.  PRODUCTION PLANNING WHEN BATCHING IS PART of the MANUFACTURING SEQUENCE , 1991 .

[27]  T. Durance.  Improving canned food quality with variable retort temperature processes , 1997 .

[28]  Eva Balsa-Canto,et al.  Improving food processing using modern optimization methods , 2003 .

[29]  Christodoulos A. Floudas,et al.  Deterministic Global Optimization in Nonlinear Optimal Control Problems , 2000, J. Glob. Optim..

[30]  Panos M. Pardalos,et al.  State of the Art in Global Optimization , 1996 .

[31]  Frank P. Incropera,et al.  Fundamentals of Heat and Mass Transfer , 1981 .

[32]  Ashim K. Datta,et al.  Computer‐Based Retort Control Logic for On‐Line Correction of Process Deviations , 1986 .

[33]  H. S. Ramaswamy,et al.  Thermal processing and quality: Principles and overview , 2007 .