Shear Values and Alkali Insoluble Collagen of Beef Biceps Femoris as Affected by Time and Temperature of Heating

The effect of heating beef cores at 55^o, 60^o, and 65^oC for 30, 60, and 120 minutes was studied. Cores were procured from three pairs of beef biceps femoris muscle from U. S. Choice steers. They were one inch in diameter and were heated in glass tubes in a thermostatically-controlled water bath. Tenderness was evaluated by Warner-Bratzler shear values. The residual alkali insoluble collagen was determined on composite samples of the sheared cores from each heat treatment. Heat treatments were replicated three times, once with each muscle pair.

Cores of muscle heated at 60^o and 65^oC were more tender than those heated at 55^oC, and those heated for 120 minutes were more tender than those heated for 30 minutes (P<0.05). The decrease in collagen content of cores heated at 65^oC for 120 minutes was greater than the decrease with any other heat treatment. The residual collagen was related to the shear values of the heat-treated cores (P<0.01) and accounted for approximately 53 percent of the increase in tenderness.