Effects of low-voltage electrical stimulation and aging on lamb meat quality

Abstract

W. 2012. Effects of low-voltage electrical stimulation and aging on lamb meat quality. Can. J. Anim. Sci. 92: 59Á66. The aim of this study was to evaluate the effect of electrical stimulation (ES) and aging time on meat quality of heavy lamb as produced in Quebec. Seventy-six Suffolk-sired crossbred male lambs were slaughtered at a target weight of 5092 kg. Half of them were electrically stimulated (ES vs. control) at 5Á10 min postmortem (21 V; 0.25 A; 60 s). Postmortem pH decline and temperature were monitored. After carcass cutting, longissimus dorsi sections were assigned to aging periods of 1, 3 or 8 d. Temperature decline was the same for both treatments (P00.749). However, ES carcasses always had a lower pH value than controls during the first 24 h (P B0.001) while the ultimate pH was equivalent (P 00.803). Tenderness, as assessed by either Warner-Bratzler shear force (39 carcasses) or sensory evaluation (35 carcasses) was enhanced by both ES (P B0.001) and aging (PB0.001). At each aging time, tenderness was greater for ES meat. In addition, only 3 d of aging were necessary for ES meat to achieve the tenderness level attained by the controls after 8 d. Sarcomeres were longer (PB0.001) in ES meat than in controls while myofibrillar fragmentation index was not affected by ES treatment (P 0 0.743). Electrical stimulation also had small effects on color parameters (a*, b* and L*; PB0.01) and flavor (P00.04). These results provide the first evidence that tenderness of the meat from heavy lambs produced and processed in Quebec could be enhanced by ES, mostly through cold shortening reduction.

Use of electrical stimulation and chilling to enhance meat tenderness of heavy lambs

“…1b). This response to low-voltage ES is in accordance with previous results obtained with the same ES system (Pouliot et al 2012a), although only half the ES time was required in the present study (30 s vs. 60 s). Genetic and pre-slaughter factors could be responsible for the variation in response to ES between the two studies as they have an impact on fibre type, metabolism and energy status.…”

“…In fact, these NES carcasses reached 108C at pH 6.4Á6.5, indicating that there is still a significant amount of ATP in the muscle at a temperature where calcium sequestration is reduced. Comparable results have been reported by Pouliot et al (2012a).…”

“…Similar results have been reported in a previous study in Quebec using the same ES system (Pouliot et al 2012a) and in other lamb studies using high-or low-voltage systems (Riley et al 1981;Kerth et al 1999;Warner et al 2005). Aging also increased L* and a* values (Table 2).…”

“…Due to their smaller size and their fibre type composition, ovine carcasses are susceptible to cold shortening and hence toughening of the meat in these conditions (Pearson and Young 1989). In fact, a recent study showed that meat tenderness from heavy lambs produced and processed in Quebec could be enhanced by electrical stimulation (ES), mostly through reduction in cold shortening (Pouliot et al 2012a). Since lamb is perceived as a premium meat in Quebec and tenderness is one of the most important factors for consumer appreciation (Safari et al 2002), established packing plant practices are needed to achieve optimal quality to meet consumer expectations and stay competitive.…”

Identification of sensory attributes, instrumental and chemical measurements important for consumer acceptability of grilled lamb Longissimus lumborum

“…However, the differences are small and there is no evidence that fast chilling the carcasses from Experimental Groups 8 and 11 without the application of electrical stimulation was successful in producing cold shortening of the muscular fibres, as described by others (Pouliot et al, 2012;Savell, Mueller, & Baird, 2005). This was confirmed by the absence of statistically significant differences in WBSF between the seven experimental groups (Table 6) and the fact that Groups 8 and 11 were not significantly less tender than other treatments (Table 3).…”