Abstract
This study was conducted to evaluate the effects of electrical stimulation (ES) on rigor mortis development, calpastafin activity, and tenderness in anatomically similar avian muscles comprised primarily of either red or white muscle fibers. Thirty-six broilers and thirty-six AUte Pekin ducks were treated with postmortem ES at the neck in a 1% NaCl solution for 2 sec on I sec off for a total of 15 sec at 450 mA. The remaining 36 birds of each type were used as non-stimulated controls. Both Pectoratis muscles were harvested from the carcasses after 0.25 h, 1.25 h, and 24 h postmortem (PM) and analyzed for pH, R-value, sarcomere length (SL), gravimetric fragmentation index (GFI), calpastatin activity, shear value, and percent cook loss. All data were analyzed within species. ES treated ducks had a lower muscle pH at 0.25 h and 1.25 h PM and higher Rvalues at 0.25 h PM compared to controls. ES treated broilers had a lower muscle pH at 1.25 h and higher R-values at 0.25 h and 1.25 h PM compared to controls, ES did not affect calpastatin activity in either broilers or ducks; however, the calpastatin activity of the broilers did decrease over the aging period time whereas that of the ducks did not. In broilers, ES decreased shear values at 1.25 h PM compared to controls. However, in the duck muscle there was no difference in shear values due to ES at any time PM, There was no effect on SL due to ES in the broiler muscle at any time PM whereas the duck had an increase in sarcomere shortening at 1.25 h PM with ES. ES-treated broilers exhibited increased myofibrillar fragmentation at 0.25 h and 1.25 h PM whereas there was no such difference over PM time in the duck muscle. Cook loss was lower for ES-treated had no effect in the ducks. These results suggest that the red fibers of the duck Pectoralis have less potential for rigor mortis acceleration due to ES than do the white fibers of the broiler Pectoralis.
Zocchi, Christine (1997). The influence of postmortem electrical stimulation on rigor mortis development, calpastatin activity, and tenderness in broiler and duck Pectoralis. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1997 -THESIS -Z63.