Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2000
Publication Date: N/A
Interpretive Summary: An accurate instrumental method for classifying beef carcasses based on ribeye tenderness has been developed. To date, efforts have been focused on prediction of ribeye tenderness because the ribeye comprises a higher proportion of total carcass value than any other cut. However, it would be desirable if an accurate prediction of ribeye tenderness also could be used to classify other cuts into tenderness groups. Thus, the objective of this experiment was to determine the effect of ribeye tenderness classification of beef carcasses on tenderness of top sirloin, top round, and bottom round cuts. At two days postmortem, carcasses were assigned to one of three tenderness classes using the MARC Beef Classification System. Tenderness ratings were lowest for the "tough" class and highest for the "tender" class for all cuts except top sirloin in which the "tender" and "intermediate" classes were not different. The tenderness ratings for the "tender" class were higher than for "commodity" beef for all cuts except the top sirloin. These results indicate that it may be possible to market all major beef cuts from a carcass identified as "tender" based on a measure of ribeye tenderness. By tenderness classifying other cuts in addition to the ribeye, the cost of implementing a system for this purpose could be greatly reduced and the amount of beef marketable as "tender" greatly increased.
Technical Abstract: The objective of this study was to determine the effect of longissimus tenderness classification of beef carcasses on tenderness of three other major muscles. Ninety-eight crossbred steers and heifers (14 to 17 mo of age) were humanely slaughtered over 10 weeks and the carcasses were chilled 48 h at 0 deg C. At 48 h postmortem, carcasses were assigned to one of three tenderness classes (tender = < 26 kg, intermediate = 26 to 42 kg, tough = > 42 kg) using slice shear force from the MARC Beef Classification System. Commodity included all samples. The longissimus thoracis, gluteus medius, semimembranosus, and biceps femoris were removed, aged at 3 deg C, and frozen at -30 deg C at 14 d postmortem. The mean slice shear force values were 20.7, 34.4, and 46.3 kg, respectively, for the "tender," "intermediate," and "tough" classes. Tenderness ratings were lowest for the "tough" class and highest (P < .05) for the "tender" class for all muscles except gluteus medius in which the "tender" and "intermediate" classes were not (P > .05) different (longissimus 7.7, 7.1, 6.3, and 7.1; semimembranosus 6.4, 5.8, 5.1, and 5.8; biceps femoris 5.9, 5.4, 4.8, and 5.4; gluteus medius 6.8, 6.5, 5.8, and 6.5, respectively, for the "tender," "intermediate," "tough," and "commodity" classes). The magnitude of the difference in tenderness rating between the "tender" and "intermediate" classes and between the "intermediate" and "tough" classes was similar for all muscles. Juiciness and beef flavor intensity ratings were not affected (P > .05) by tenderness class in any muscle. These data indicate that early-postmortem longissimus slice shear force could be used to classify top sirloin, top round, and bottom round cuts for tenderness.