Although contributing to the nutritional quality of the foods we consume, proteins also act as integral components by virtue of their diverse functional properties. The expression of these functional properties during the preparation, processing and storage of foods is largely dictated by changes to the structure or structure-related properties of the proteins involved. This work describes the nature of structure-function relationships so that the use of food protein sources can be optimized. The first section uses food systems as examples to demonstrate the intricate nature of the structure-function relationship. Later chapters discuss the techniques which are used to examine structural parameters or establish relationships between protein structure and function. This guide should prove useful for food chemists, scientists and technologists, and can serve as a reference for students of this field.