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.

Effects of skeletal separation method and postmortem ageing on carcass traits and shear force in cull cow beef

“…However, the relative increase in sarcomere length from skeletal cuts in the present study was much lower than previous findings Ludwig et al 1997) evaluating steer and heifer carcasses altered at the 12th/13th vertebrae. The effect on sarcomere length from skeletal cuts in the present study is similar to those found by Beaty et al (1999) who applied skeletal cuts to the thoracic vertebra and pelvic bone, while exceeding the increases in sarcomere length in the posterior longissimus lumborum from severing the 6th thoracic and 5th lumbar vertebrae (Aalhus et al 1999). Sarcomere length in the loin eye was greater (P < 0.04) with separation at the 12/13th site as compared with the 11/12th site.…”

“…Shear force in the posterior loin was not affected (P = 0.69) by skeletal separation (Table 2), which is in contrast to previous studies where shear force was decreased in the longissimus lumborum when skeletal cuts were made between the 12th/13th vertebrae with additional cuts to the pelvic bone (Aalhus et al 1999;Beaty et al 1999). However, Ludwig et al (1997) found a nonsignificant decrease in shear force when the Tendercut process was applied to the posterior loin.…”

“…Although greater sarcomere lengths tend to be associated with more tender beef (Hostetler et al 1972), researchers (Shanks et al 2002;Sorheim and Hildrum 2002) have noted that increases in sarcomere length driven by skeletal separation treatments are not always associated with improvements in beef tenderness whether assessed by shear force or a specific taste panel tenderness attribute. Sarcomere length increased for SM and ST muscles with Tendercut processing of the round (Beaty et al 1999;Shanks et al 2002). Tendercut processing did not affect sarcomere lengths of BF and RF muscles in the Shanks et al (2002) study, in contrast to increasing sarcomere length in work by Beaty et al (1999) and Wang et al (1994).…”

“…Sarcomere length increased for SM and ST muscles with Tendercut processing of the round (Beaty et al 1999;Shanks et al 2002). Tendercut processing did not affect sarcomere lengths of BF and RF muscles in the Shanks et al (2002) study, in contrast to increasing sarcomere length in work by Beaty et al (1999) and Wang et al (1994). Shanks et al (2002) concluded that the differences in magnitude of response for sarcomere length among muscles were probably influenced by the proximity of the individual muscle in relation to skeletal separation point and by muscle fibre orientation in relation to tension.…”

Factors affecting beef palatability &mdash; farmgate to chilled carcass

“…The main advantage over tenderstretch is that the sides are conventionally hung. Results to date suggest that Tendercut is an effective means for improving tenderness (Wang et al 1994(Wang et al , 1996Beatty et al 1999) in commercially valuable hindquarter muscles.…”