ABSTRACT
Cereals are complex foods, and in order to understand their textural characteristics it is important to study their mechanical properties as they vary with composition and structure. The combination of the protein and starch polymers and the addition of other constituents in the process, such as water and sugar, alters the glass transition of the system. Many tests for cereal products are based on those that are well developed in metallurgy and adapted in polymer science. They are often based on a universal testing machine, and in some cases there is an overlap with instrumental tests. A number of general texture measuring devices has been used for testing instrumental texture of extrudates. Instrumental tests at higher shear rates are often based on pendula and are justified by the higher rates than are often possible using universal testing machines. Extrudates are often solid foams, which can be understood from the matrix properties and porosity, to a first approximation using models.
