Relationship between the sponge structure of starch bread and its mechanical properties

To obtain a better understanding of the relationship between the sponge structure of starch bread and its mechanical properties, a theory that had been developed for other cellular solids was applied. This theory describes the relationship between the mechanical properties (Young's modulus, critical stress) and cell geometry. The results obtained for Young's modulus fitted well with the theory. The failure behaviour of wheat starch bread could be described quite well by the plastic yielding mechanism. However, data for the critical stress for potato starch bread showed less agreement with the theory. From these results, it is concluded that the large variation in the sizes of the cells and thicknesses of the beams strongly affects the fracture behaviour of 'beams' building up the starch bread. (C) 1996 Academic Press Limited