Food Extrusion Process Scale-Up and Process Transfer: Witchcraft or Science?

Scaling an extrusion process (e.g., from pilot scale to production scale) or transferring a process from one type of extruder to another (of the same or different makes/models), involves an understanding of many process variables. This book takes a complex task, commonly approached largely on an empirical (or "trial and error") basis and shows how scientific and engineering principles can be assembled to design the required outcome - that is, the manufacture of the same product.

Following a brief review of extrusion theory, the book discusses methods to quantify both material rheology and the extrusion process. Principles and application of "Dimensional Analysis" techniques are also presented.

This is then used as a basis for a planned approach to scale-up and/or process transfer. Analysis and scale-up of extrusion dies are covered as separate topics. Worked examples - taken from actual industrial scale-up experience - are used to demonstrate the methods. The aim is to provide readers with a science-based approach to this topic, which applies to real industrial processes. The limitations inherent in scaling the process are also discussed, along with an outline of how small-scale trials should be planned so that processes are more scalable.

Dennis Forte graduated in chemical engineering and spent ten years with the Mars Corporation in both process and product development roles within the areas of confectionery and pet food extrusion technologies. He moved on to work with The Uncle Toby's Company as the Process Engineering Manager, where he was actively involved in the quantification and optimisation of ready-to-eat breakfast cereal and snack manufacture. He is has been practicing as an independent engineering consultant to the food industry since 2000, providing technical support, design expertise and training to a broad range of manufacturers.