EFFECT OF STRAIN LEVEL AND STORAGE TIME ON THE RECOVERABLE WORK OF COMPRESSED BREAD CRUMB

Cylindrical specimens of bread crumbs were subjected to a compression-decompression cycle using a computer interfaced Universal Testing Machine during 11 days of storage at ambient temperature. The strain (% deformation) was set at various levels in the range of 20-80%. The overall work per unit volume, calculated from the area under the stress-strain curve, increased exponentially with the imposed strain while the percent recoverable work, calculated from the area under the decompression curve, decreased exponentially with the strain. The loss of elasticity that accompanies bread aging was clearly manifested in the percent recoverable work, irrespective of the imposed strain. It declined in a manner that could be described by a power law or an exponential decay model at the same degree of fit as judged by statistical criteria.