Engineering for food processes is no different from other process industries in that the analysis of unit operations is similar. Many unit operations are quite simple. The difficulty arises when one discovers that physical properties for the materials being processed are not available. Worse still is learning that the systems are changing due to some sort of unexplained physiochemical reactions. Foods systems are nonhomogeneous and very complex. Dealing with these complexities has required much effort on the part of both academia and industry. Despite these complications, the engineer in industry needs to find a way to design, build and control processes. One approach is to examine designs over a range of varying physical properties and optimizing on that basis. Another is to model the unit operation and rely on experimentation to determine the apparent physical properties. Provided process similarity is preserved, these properties can be used in larger scale systems. If we can be sure process conditions are the same from one system to the next, knowledge of physical properties during processing may become unimportant. This paper will discuss the problems encountered, and the resolution of these problems, first in the simple design of flow manifolds for meat emulsion systems, and then in the more complex case of extrusion system scale-up for cereal products.
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