FACTORS INFLUENCING STRESS CRACKS IN FRANKFURTERS DURING COOKING AND IN STORAGE

摘要

ABSTRACTBiological and food materials can develop stress cracks under the influence of variable temperature and moisture gradients. Frankfurter sausages, from a molecular concept are a heterogenous system, but for engineering purposes the molecular structure may be disregarded and can be treated as a continuum. In the present investigation a continuous Maxwell model was assumed to represent the frankfurters subject to variable temperature and moisture conditions. Utilizing the techniques of linear viscoelasticity, an expression for the mechanical stiesses in a cylinder was obtained. Uniaxial modulus as a function of time and temperature was determined experimentally and the resulting data were analyzed to obtain time‐temperature shift factors, relaxation time and a master curve for the modulus. The temperature as a function of radius and time was determined during cooking, and an algebraic expression for axial, tangential and radial stresses was developed. The maximum shearing stresses exceeded failure stress of the frankfurters, thus explaining the development of crack