Changes in mechanical strength of intramuscular connective tissue during postmortem aging of beef.

We studied changes in mechanical strength during postmortem aging of bovine semitendinosus muscle using intramuscular connective tissue (IMCT) preparations from muscle stored at 4 degrees C. In the preparation, muscle fiber elements were removed, leaving a virtually intact structure of the endomysium and perimysium. The shear-force value of the IMCT preparation remained unchanged up to 10 d postmortem and decreased linearly thereafter. The yield of the perimysial fraction, which was measured as an indicator of mechanical properties of the perimysium, remained almost unchanged up to 14 d postmortem, and decreased gradually thereafter. These results suggest that the mechanical strength of the intramuscular connective tissue changes slowly during postmortem aging of beef; it remains almost unchanged for up to 10 d postmortem and progressively decreases thereafter. Thus, intramuscular connective tissue seems to affect beef tenderization in extended aging.