Relationships Among Shear Values, Sarcomere Lengths and Cooling Procedures in Turkeys

SUMMARY– Studies were conducted to determine the effect of different chilling procedures after slaughter on the tenderness of the breast and thigh muscles of turkeys as measured by shear press values. Measuring sarcomere lengths determined the effect of the chilling procedures on length of muscle fibrils and their correlation with shear press values. Three chilling treatments were used: (1) 16°C for three hr; (2) 16°C for 45 min, 8°C for 45 min, and 0°C for 90 min; and (3) 0°C for 3 hr. The 0°C treatment for 3 hr resulted in a significant increase in shear press values for thigh muscle in both studies. Shear values also increased for breast muscle in the same 0°C treatment group, but not significantly. Shear values for the left thigh muscle were significantly higher than for the right in Experiment I, while in Experiment II hens had significantly higher thigh shear values than toms. In Experiment I with younger birds, shear values were significantly higher in the breast muscle of toms than in hens. The surface slice of 3 slices of breast muscle had higher shear values in both experiments. Chilling treatments resulted in a progressive shortening of sarcomere lengths in breast and thigh muscles with decreasing temperature, and the sarcomere lengths were shorter for breast muscle than for thigh. No significant correlations were found between shear values of breast and thigh muscles, or between shear values and sarcomere length.