EARLY POSTMORTEM SKELETAL ALTERATIONS EFFECT ON SARCOMERE LENGTH, MYOFIBRILLAR FRAGMENTATION, AND MUSCLE TENDERNESS OF BEEF FROM LIGHT‐WEIGHT, BRANGUS HEIFERS

ABSTRACT Approximately 2 h after exsanguination, two skeletal cuts (TC) were made on randomly selected sides from 13 light‐weight, Brangus heifers; companion sides served as untreated controls (C). After a 24‐h chill period, four muscles (Longissimus muscle from the IMPS#112A ribeye roll, LT, and from the IMPS#180 strip loin, LL; Biceps femoris, BF; Semitendinosus, ST; and Semimembranosus, SM) were excised from each side, vacuum‐packaged, and aged for 7 days. Five 2.54‐cm thick steaks were cut from each of the muscles to determine the effectiveness of the TC treatment on sarcomere length (SL), myofibrillar fragmentation index (MFI) and cooked beef tenderness. The LT and LL steaks from TC‐carcasses had longer (P < 0.05) sarcomeres, and the TC treatment decreased (P < 0.05) Warner‐Bratzler shear (WBS) force values for the LT and LL by 35.8 and 33.2%, respectively. Moreover, SL of the muscles from the round were also increased (P < 0.05) by the TC procedure, but WBS force values were not different (P > 0.05) from C. Muscles from the TC sides had similar (P > 0.05) MFI values to those from control sides. This study demonstrated that the TC procedure, when applied 2 h postmortem, can effectively improve cooked beef tenderness of the Longissimus muscle.