Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 10, 2003
Publication Date: March 20, 2004
Citation: Shackelford, S.D., Wheeler, T.L., Koohmaraie, M. 2004. Evaluation of sampling, cookery, and shear force protocols for objective evaluation of lamb longissimus tenderness. Journal of Animal Science. 82:802-807. Interpretive Summary: In order to determine if there are differences in lamb meat tenderness between breeds or lines of sheep, researchers must be able to accurately and efficiently measure tenderness on a large number of samples. Thus, experiments were conducted to determine if advances that had been made in the objective assessment of beef tenderness could be adapted for evaluation of lamb. It was determined that lamb loin muscle tenderness could be accurately evaluated using rapid cookery with a belt grill and rapid measurement of meat tenderness using a procedure called slice shear force. Use of belt grill cookery and the slice shear force technique could reduce time requirements which would reduce research costs.
Technical Abstract: Experiments were conducted to compare the effects of two cookery methods, two shear force procedures, and sampling location within non-callipyge and callipyge lamb longissimus on the magnitude, variance, and repeatability of longissimus shear force data. In Exp. 1, 15 non-callipyge and 15 callipyge carcasses were sampled and Warner-Bratzler shear force (WBS) was determined for both sides of each carcass at three locations along the length (anterior to posterior) of longissimus and slice shear force (SSF) was determined for both sides of each carcass at one location. For approximately one-half of the carcasses within each genotype, longissimus chops were cooked for a constant amount of time using a belt grill and chops of the remaining carcasses were cooked to a constant endpoint temperature using open-hearth electric broilers. Regardless of cooking method and sampling location, repeatability estimates were at least 0.8 for longissimus WBS and SSF. For WBS, repeatability estimates were slightly higher at the anterior location (0.93 to 0.98) than the posterior location (0.88 to 0.90). The difference in repeatability between locations was probably a function of a greater level of variation in shear force at the anterior location. For callipyge longissimus, WBS was higher (P < 0.001) at the anterior location than at the middle or posterior locations. For non-callipyge longissimus, WBS was lower (P < 0.001) at the anterior location than at the middle or posterior locations. Consequently, the difference in WBS between callipyge and non-callipyge longissimus was largest at the anterior location. In Exp. 2, longissimus chops were obtained from matching locations of both sides of 44 non-callipyge and 43 callipyge carcasses. Chops were cooked with a belt grill and SSF was measured and repeatability was estimated to be 0.95. Repeatable estimates of lamb longissimus tenderness can be achieved either through cooking to a constant endpoint temperature with electric broilers or cooking for a constant amount of time with a belt grill. Likewise, repeatable estimates of lamb longissimus tenderness can be achieved with WBS or SSF. Use of belt grill cookery and the SSF technique could reduce time requirements which would reduce research costs.