Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/10/2010
Publication Date: 6/20/2010
Citation: King, D.A., Shackelford, S.D., Wheeler, T.L. 2010. Relative Contribution of Animal and Muscle Effects to Variation in Beef Lean Color Stability. Proceedings Reciprocal Meat Conference. 63:61. Interpretive Summary:
Technical Abstract: Our objective was to determine the extent to which animal effects influence variation in beef lean color stability in comparison to muscle and quality grade effects. Carcasses (n = 100) equally representing the US Choice and Select grades were selected on five days from a commercial beef processing facility. At 14 d postmortem, steaks were cut from the longissimus lumborum (LL), semimembranosus (SM), biceps femoris (BF), gluteus medius (GM), triceps brachii (TB), rectus femoris (RF), vastus lateralis (VL), semitendinosus (ST), infraspinatus (IF), teres major (TM), biceps femoris ischiatic head (BFIH), biceps femoris sirloin cap (BFSC), and gracillus (GR) muscles and placed in simulated retail display. Instrumental color values [CIE L*, a*, b*, and overall color change (delta E)] values were determined on d 0, 1, 3, 6, and 9 of display. As expected, initial color and the rate and extent of color change differed substantially across muscles within a carcass. Coefficients of variation (CV) indicated that variation in color change was highest for LL particularly on d 9, when the CV for LL was 49.0 compared to a range of 13.6 to 34.0 for other muscles. However, when d 9 delta E values for LL were compared to d 6 delta E values of other muscles, all muscles had correlation coefficients greater than 0.5 except the IS and TM. Correlations between LL delta E values on d 9 and the d 9 delta E values of other muscles were generally much lower, primarily because most of the steaks from some muscles had completely discolored, thus variation was reduced in the d 9 delta E values for those muscles. Variance component analysis indicated that quality grade did not contribute to the variance in delta E on any day of display. On d 1, selection day, animal, muscle, and residual effects accounted for 3.8, 5.1, 18.4, and 72.8% of the variance in delta E. On d 3, these factors contributed 12.2, 15.9, 33.6, and 38.5% of the variance in delta E, respectively. On d 6, selection day, animal, muscle, and residual effects accounted for 23.4, 19.8, 30.0, 27.2% of the variation in delta E, respectively. On d 9, the contribution of animal and muscle were similar (23.5 and 23.3, respectively), whereas selection day and residual effects accounted for 4.1 and 48.9% of the variance in color change, respectively. These results suggest that animal and muscle effects are important contributors to variation in beef lean color stability, and that the relative contribution of animal effects increases as time in display increases. These data also suggest that technology effectively influencing LL color stability would have similar effects on the remainder of the carcass.