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

Pouliot, E., Gariepy, C., Theriault, M., Avezard, C., Fortin, J., Simmons, N. J. and Castonguay, F. W. 2012. Effects of low-voltage electrical stimulation and aging on lamb meat quality. Can. J. Anim. Sci. 92: 59-66. 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 48-52 kg. Half of them were electrically stimulated (ES vs. control) at 5-10 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 (P = 0.749). However, ES carcasses always had a lower pH value than controls during the first 24 h (P < 0.001) while the ultimate pH was equivalent (P = 0.803). Tenderness, as assessed by either Warner-Bratzler shear force (39 carcasses) or sensory evaluation (35 carcasses) was enhanced by both ES (P < 0.001) and aging (P < 0.001). At each aging time, tenderness was greater for ES meat. In addition, only 3d of aging were necessary for ES meat to achieve the tenderness level attained by the controls after 8 d. Sarcomeres were longer (P < 0.001) in ES meat than in controls while myofibrillar fragmentation index was not affected by ES treatment (P = 0.743). Electrical stimulation also had small effects on color parameters (a*, b* and L*; P < 0.01) and flavor (P = 0.04). 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.