Pre-rigor carcass stretching counteracts the negative effects of high rigor temperature on tenderness and water-holding capacity – using lamb muscles as a model

Abstract

Abstract. High pre-rigor muscle temperature has negative consequences on quality and has been predominantly studied in the excised longissimus muscle of beef and lamb carcasses. There is little data on other muscles, the application in whole carcasses or potential amelioration techniques such as stretching. This study evaluated the effects of electrical stimulation, high pre-rigor temperature and stretching of lamb sides on quality traits and protein denaturation in four leg muscles [gluteus medius (GM), rectus femoris (RF), semimembranosus (SM) and semitendinosus (ST)]. Twenty lamb carcasses were used with two electrical stimulation treatments (stimulated or non-stimulated, +/À) and two pre-rigor temperature treatments (chilled at 2 C directly after slaughter, or held in 37 C water for 4.5 h before transfer to a 2 C chiller) applied. One side of each carcass was suspended from the Achilles tendon, whereas the other side was stretched by allowing the leg to drop and tying it to the ribs. Electrical stimulation did not influence the different traits except for pH fall post slaughter and myosin denaturation. Stretching resulted in greater muscle and sarcomere lengths for the GM, SM and ST, but a decrease in sarcomere length for the RF. For the non-stretched GM and SM, the 37 C treatment resulted in tougher meat at 1 and 8 days post mortem compared with the 2 C treatment. In contrast, the stretched 37 C treatment resulted in more tender meat for the GM, SM and ST at 1 day post mortem compared with the 2 C treatment. For all muscles, the 37 C treatment resulted in a decrease in the waterholding capacity (increased purge, surface exudate and cooking losses). The magnitude of this effect was generally diminished by stretching for the GM, SM and ST, but for the RF, (which was not stretched by the treatment) this effect was reversed. The 37 C treatment resulted in paler meat (increased L*-values) for the GM, SM and ST relative to the 2 C treatment. The observed effects of the 37 C treatment on water-holding capacity and colour could be explained by the effects of this treatment on indicators of protein denaturation (sarcoplasmic protein solubility and myofibrillar ATPase activity), which were decreased for the GM, SM and ST. The response to both temperature and stretching varied between the muscles, due to different anatomical location and also due to postulated differences in the fibre types. In conclusion, pre-rigor stretching of lamb sides can counteract the negative effects of high early postmortem temperature on tenderness and water-holding capacity for those muscles that are stretched as a result of this hanging method.

Muscle metabolism in sheep and cattle in relation to high rigor temperature – overview and perspective

“…Unfortunately, the number of carcasses tender-stretched was limited compared with samples in the normal pH-temperature range, but similar results were presented by Warner et al (2014b) and Kim et al (2014a) for sheep meat, while positive effects on WHC were also demonstrated in certain cases. The m. rectus femoris (RF) showed increased cooking losses , whereas no effect was recorded for m. longissimus lumborum (LL), and a clear positive effect was apparent for m. semimembranosus (SM) (Kim et al 2014a).…”

“…Working on different muscles on sheep carcasses, Warner et al (2014b) found no shortening effect due to high rigor temperatures for m. gluteus medius (GM), m. semitendinosus (ST) and SM cuts. The RF cuts shortened, probably due to the anatomical position and/or muscle-fibre type of this muscle but surprisingly also showed increased tenderness (lower Warner-Bratzler shear force) for non-stretched muscle.…”

Effect of slaughter season on postmortem metabolic characteristics of muscle in the dromedary camel (Camelus dromedarius)

“…The decrease of water-holding capacity during summer could be attributed to the high muscle temperature recorded during this season. This finding was in accordance with those of Wang et al (2009) in broilers, Kim et al (2012) in cattle, and Warner et al (2014) in lambs. These previous authors reported that high temperature exposure induces excessive water loss from muscles.…”

Impacts of hanging method and high pre-rigor temperature and duration on quality attributes of ovine muscles

“…Prevention against the toughening effect of shortening under high pre-rigor temperatures can be achieved by alternative carcass suspension (tenderstretching, superstretching, etc. ), or by tightly wrapping pre-rigor excised muscles to restrain shortening (Rosenvold et al 2008;Warner et al 2014b). In contrast, Kim et al (2012) observed no significant protective effect against toughening by restraining muscles exposed to high pre-rigor temperatures.…”

“…A square bipolar wave form was applied, providing 157-mA peakto-peak (28-33V) with a frequency of 14 Hz for a duration of 60 s. One side was then suspended from the tailbone and the other side from the aitchbone. For the side suspended by the aitchbone, the hindleg was tightly pulled down proximally, (closer to the ribs) and tied into the ventral (underside of body) surface, thus resulting in a stretching action being applied to the leg muscles; see photo in Warner et al (2014b) Then a temperature conditioning treatment was applied being: (i) Long/37 C -carcass placed in a 37 C vat of water for 4.5 h and then placed in a 2 C chiller (same conditions as Warner et al (2014b), (ii) Medium/37 C -carcass placed in a 37 C vat of water for 3 h and then placed in a 2 C chiller, (iii) Short/37 Ccarcass placed in a 37 C vat of water for 1.5 h and then placed in a 2 C chiller and (iv) Conventional 2 C -carcass placed into 2 C chiller where the carcass was placed directly into a chiller at 2 C after leaving the slaughter floor.…”