Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 2001
Publication Date: March 20, 2002
Citation: Wheeler, T.L., Shackelford, S.D., Koohmaraie, M. 2002. Technical note: sampling methodology for relating sarcomere length,collagen concentration, and the extent of postmortem proteolysis to beef and pork longissimus tenderness. Journal of Animal Science. 80:982-987. Interpretive Summary: Numerous experiments have been conducted to determine the association of various muscle traits with variation in meat tenderness. Samples for measurement of cooked ribeye tenderness and samples for measurement of muscle traits have almost always come from different steaks or chops. These samples sometimes were from adjacent steaks or chops and sometimes were from steaks or chops 2 to 8 inches or more from the location used for tenderness measurements. However, it would seem likely that in order to most accurately determine the relationship between tenderness and other muscle traits, samples for the measurements of all traits should be from the same location. Thus, the objective of this study was to compare the relationship between meat tenderness and three muscle traits (muscle shortening, connective tissue concentration, and muscle protein degradation) when sampling from a separate raw steak or chop and sampling from the same cooked meat used to measure shear force. The relationship between the muscle traits and shear force was at least as strong or stronger for cooked samples than for raw samples. When muscle shortening, collagen concentration, and muscle protein degradation were measured on cooked meat, combined they explained more of the variation in meat tenderness than when measured on a separate raw sample. For future experiments to determine the relationship between muscle traits and meat tenderness, measurements of all traits should be made on the same cooked sample.
Technical Abstract: The objective of this study was to determine the effect of sampling the cooked meat after shear force measurement or a separate raw sample on the relationship between longissimus tenderness and measures of biochemical meat traits. Tenderness rating ranged from 3.1 to 7.6 for beef and 4.1 to 7.4 for pork. The coefficient of variation was lower for sarcomere length than all other traits. Simple correlation coefficients between measurements on raw and cooked samples were 0.58 and 0.11 (sarcomere length), 0.66 and 0.59 (collagen), and 0.74 and 0.76 (desmin degradation), respectively, for beef and pork. Simple correlation coefficients between biochemical traits and measures of tenderness were higher or not different for cooked than for raw samples in all but one comparison. Correlation coefficients between biochemical traits and tenderness rating for raw and cooked samples were 0.38 and 0.22 (sarcomere length), -0.12 and -0.45 (collagen), and 0.48 and 0.80 (desmin degradation), respectively, for beef, and 0.14 and 0.15 (sarcomere length), -0.38 and -0.33 (collagen), and 0.53 and 0.67 (desmin degradation), respectively, for pork. The coefficients of determination for explaining variation in tenderness rating using sarcomere length, collagen concentration, and desmin degradation for raw and cooked samples were 0.43 and 0.73 (beef) and 0.48 and 0.57 (pork), respectively. These data indicate that measurements of biochemical traits on the cooked meat after shear force determination account for more of the variation in measures of tenderness than measurements on a separate raw sample.