Post-mortem evolution of rheological properties of the myofibrillar structure

The post-mortem evolution of the rheological behaviour of beef muscle has been studied with the SATA compressive device. The resistance and elasticity of the muscle tissue, measured at low strain, refer to the myofibrillar structure and provide an indication of the advance of the rigor maturation process. These parameters have been used to quantify the electrical stimulation effect on Longissimus dorsi and Semi-membranosus muscles. An empirical model is proposed for the post-mortem evolution of the resistance and provides three parameters-the initial rate of rigor onset, the time of rigor and the residual stress after ageing. On the other hand, parameters obtained at high strain refer mainly to the connective tissue. The particularly high stress developed by the pre-rigor muscle, however, is presumed to be associated with the myofibrillar component.