ABSTRACT
Food polymers often consist of long chained molecules such as starch, proteins, lipids, and polysaccharides that are viscoelastic. Viscoelasticity generates time dependency and manifests itself in recoil and normal forces. Deformations, which occur during the processing of foods, are generally a combination of shear and extensional flows. Examples include dough sheeting, extrusion, mixing, and protein spinning. Models able to describe the behavior of food materials in all components of stress, strain, and strain rates are called constitutive models (Bird et al., 1987). This chapter will review both linear and nonlinear integral and differential models which have been used with food materials in the authors’ laboratory at Rutgers University.
