Effect of 3 postmortem electrical stimulation treatments on the quality of early deboned broiler breast meat

The present experiment was carried out to evaluate the effects of electrical stimulation (ES) immediately prescalding (PS), ES immediately postdefeathering (PD), or PS combined with PD (PSPD) on the quality of early deboned (2 h) broiler breast muscles, pectoralis major (fillets), and pectoralis minor (tenders). No stimulation, early-deboned (2 h), and 24-h deboned (24 h) fillets were used for the comparison. The 42-d-old broiler carcasses were electrically stimulated with pulsed current at 200 V for 30 s over a 90-s time interval (total of 1 min over 180 s for PSPD), and breast meat was deboned 2 h postmortem. Quality indicators evaluated were CIE L*, a*, and b* color and pH of the raw fillets and cook yields and Warner-Bratzler (WB) shear force of the fillets and tenders. There were no differences in raw fillet color, pH, and cook yields of both the fillets and tenders between the 3 ES treatments. Effects of different ES treatments on meat WB shear force values varied with breast muscles. For the fillets, the average WB shear force values of both the PS and PSPD samples, which were not different from each other, were significantly lower than those of the PD samples. For the tenders, there were no differences in the average shear force values between the 3 ES treatments. Regardless of ES treatment and breast muscle, early deboned broiler breast meat from ES carcasses required significantly less force to shear than the 2-h control. These results indicate that ES can tenderize early deboned poultry breast muscles; however, the effectiveness of ES tenderization varies with ES treatments for the fillets. The PS treatment is more effective in reducing fillet shear values than PD, and there is no further reduction in shear values with PSPD compared with the PS treatment.

The influence of postmortem electrical stimulation on rigor mortis development, calpastatin activity, and tenderness in broiler and duck pectoralis

This study was conducted to evaluate the effects of electrical stimulation (ES) on rigor mortis development, calpastatin activity, and tenderness in anatomically similar avian muscles composed primarily of either red or white muscle fibers. A total of 72 broilers and 72 White Pekin ducks were either treated with postmortem (PM) ES (450 mA) at the neck in a 1% NaCl solution for 2 s on and 1 s off for a total of 15 s or were used as nonstimulated controls. Both pectoralis muscles were harvested from the carcasses after 0.25, 1.25, and 24 h PM and analyzed for pH, inosine:adenosine ratio (R-value), sarcomere length, gravimetric fragmentation index, calpastatin activity, shear value, and cook loss. All data were analyzed within species for the effects of ES. Electrically stimulated ducks had a lower muscle pH at 0.25 and 1.25 h PM and higher R-values at 0.25 h PM compared with controls. Electrically stimulated broilers had a lower muscle pH at 1.25 h and higher R-values at 0.25 and 1.25 h PM compared with controls. Muscles of electrically stimulated broilers exhibited increased myofibrillar fragmentation at 0.25 and 1.25 h PM, whereas there was no such difference over PM time in the duck muscle. Electrical stimulation did not affect calpastatin activity in either broilers or ducks; however, the calpastatin activity of the broilers did decrease over the aging time period, whereas that of the ducks did not. Electrical stimulation decreased shear values in broilers at 1.25 h PM compared with controls; however, there was no difference in shear values of duck muscle due to ES at any sampling time. Cook loss was lower for electrically stimulated broilers at 0.25 and 1.25 h PM compared with the controls, but had no effect in the ducks. These results suggest that the red fibers of the duck pectoralis have less potential for rigor mortis acceleration and tenderization due to ES than do the white fibers of the broiler pectoralis.

Quality and sensory characteristics of selected post-rigor, early deboned broiler breast meat tenderized using hydrodynamic shock waves

Our first objective was to determine the effects of explosive amount and distance of the explosive to the meat surface in the Hydrodyne process on broiler breast tenderness. Early deboned (EB) breasts were removed immediately after initial chill (45 min postmortem), stored for 24 h (4 C), and subjected to one of four Hydrodyne treatments (200 g at 20 cm, 350 g at 23 cm, 275 g at 20 cm, or 350 g at 20 cm). Breasts were water-cooked (78 C internal). Hydrodyne treatment (HYD) of 350 g at 20 cm produced the greatest reduction (28.3%) in Warner-Bratzler shear (WBS, 1.9-cm wide strips). This combination was the only treatment to improve tenderness (peak force 4.3 kg) to a level equivalent (P > 0.05) to aged controls (CA; peak force 3.1 kg). The second objective was to determine the quality and sensory characteristics of Hydrodyne-treated (350 g explosive at 20 cm) broiler breasts as compared with CA and EB. The WBS values (1.0-cm wide and thick strips) for CA (1.56 kg) were different from both HYD (3.7 kg) and EB breasts (4.7 kg). The CA resulted in more tender, flavorful, and juicer breasts than EB and HYD. The EB was higher in initial moisture release than HYD. The EB breasts with tenderness problems can be tenderized by the Hydrodyne process based on WBS results. However, higher levels of explosive may be required to optimize the tenderness improvement of EB breasts that vary significantly in initial tenderness.

Tenderness of broiler breast fillets from carcasses treated with electrical stimulation and extended chilling times

Postmortem electrical stimulation (ES) (450 V, 450 mA, 2 s on, 1 s off for five pulses) has been shown to decrease the toughness associated with early deboning. Most studies involving this system have been concerned with obtaining "acceptable" tenderness in fillets deboned at about 1 h postmortem, the time of carcass exit from an immersion chiller. However, the effects of ES combined with deboning at 2 h postmortem needs to be evaluated because some processors are considering extended immersion chilling and those already using air chilling require approximately 2 h for this process. Two 32-bird trials were conducted to compare tenderness in broiler breast fillets from ES-treated carcasses deboned at 1 and 2 h postmortem and fillets from control (C) carcasses deboned at 1 and 4 h postmortem. The Allo-Kramer shear value means of ES-2 h and C-4 h fillets were not different from each other and were significantly lower than that of the ES-lh fillets, which was significantly lower than the C-lh fillets. There was no significant difference among treatments associated with thaw loss or cook loss. The ES-2 h, ES-1 h, and C-4 h samples had significantly higher R-values and lower pH values than the C-1 h samples, indicating more advanced rigor development. These results indicate that deboning fillets from ES-treated carcasses at 2 h postmortem yields meat with a tenderness equivalent to the value reached with 4 h aging on the carcass. This is a 50% reduction in the time needed to achieve this level of tenderness.

Commercial implementation of postmortem electrical stimulation

Postmortem electrical stimulation (ES) of meat-producing species is not a new technology but has recently been adapted for commercial use with poultry. Unlike its use in red meats to reduce the inherent toughness and facilitate grading, the application of ES in poultry is to reduce the need for aging carcasses before deboning by reducing the toughening that occurs when the meat is deboned early after death. The current practice of aging intact carcasses or breast halves 4 h or more prior to deboning costs the industry millions of dollars in lost yield and creates logistical problems in plants. Electrical stimulation reduces the need for aging by accelerating the energy depletion involved in rigor mortis development to reduce the shortening-related toughness of early deboning. Some ES systems have the additional effect of inducing physical disruption in the muscle, reducing muscle integrity and counteracting the toughness induced by early deboning. Several ES systems have been reported in the literature with some having been recently developed into commercial-scale devices. With this new technology and the growing pressure on processors to maximize operating efficiencies, processors will need to evaluate their tenderness management programs and customer demands to determine the role ES can play in their operations.

Assessment of three devices used in shear tests of cooked breast meat

Methods that increase processing efficiency to save energy costs and to improve yield and volume must be evaluated in terms of maintaining or improving final product quality. Shear tests measure the force to cut through fibers of cooked samples. They are the simplest and most common tests used to document cooked meat texture. However, information obtained from shearing devices that perform in a similar way may not be interchangeable. In this study, three shearing devices were assessed. Eight treatments were imposed on broiler breasts processed under commercial conditions to represent ranges of texture characteristics. Treatments included electrical stimulation (S), or no stimulation (NS) of carcasses; postchill deboning at 2 or 6 h; and marination (M), or no marination (NM). Shear force values of cooked breasts were obtained from the benchtop Warner-Bratzler (BT-WB) machine, the Warner-Bratzler blade attachment (TA-WB) and a 45 degrees chisel-end blade attachment (TA-WD). The TA-WB and TA-WD were attached to Model TA.XT2 texture analyzer. For each device, shear value differences were significant (P < 0.05) for deboning time. Marination effects were significant (P < 0.05) for BT-WB and TA-WB. Stimulation by debone interactions were significant (P < 0.05) for BT-WB and TA-WD. The TA-WD values varied the greatest over all treatments (SD = 5.52; SE = 0.65). Variations of BT-WB and TA-WB shear values were similar (SD = 3.25, 2.97, respectively; SE = 0.38, 0.35).

Meat quality of broiler breast meat following post-mortem electrical stimulation at the neck

This experiment was conducted to evaluate the effects of electrical stimulation (ES) on breast fillets harvested at 1 h post-mortem and individually quick frozen (IQF) or aged on ice (ICE). Twelve birds were electrically stimulated (450 V, 750 mA, 2 s on/1 s off for 15 s) at the neck in a saline bath. Twenty-four unstimulated birds were used as controls. Breast fillets were harvested at 1 h post-mortem from ES and control carcasses or at 4 h post-mortem from control carcasses and were either IQF or ICE until 24 h post-mortem. Fillets were then analyzed for shear value, pH, R value, and color. Electrical stimulation significantly reduced shear values compared to the 1 h controls for both IQF and ICE treatments. The ICE fillets deboned at 1 h from ES-treated carcasses had shear values similar to those of ICE fillets deboned from the 4 h controls. Electrical stimulation increased the percentage of shear values at or below 8 kg/g for the fillets from ES-treated carcasses compared to the 1 h controls. Electrical stimulation accelerated the normal post-mortem decline in pH and increase in R value. There was no significant difference in L* or a* values between the fillets held for 1 or 24 h. The results suggest that by electrically stimulating carcasses at the neck using a saline bath, the aging period could be eliminated by removing fillets immediately after chilling at 1 h, decreasing the costs associated with aging whole carcasses or front halves.

Muscle metabolism and meat quality of Pectoralis from turkeys treated with postmortem electrical stimulation

This experiment was conducted to evaluate the effects of electrical stimulation (ES) on muscle metabolism and breast meat quality in turkeys. Thirty-six turkey hens were either ES at the neck in a saline bath (570 V, 450 mA, AC, 60 Hz, 2 s on 1 s off for 10 pulses) or used as unstimulated controls. One breast fillet from all carcasses was harvested at 2 h postmortem. The opposite fillet was harvested from the ES carcasses at 8 h postmortem and from the unstimulated controls at either 8 or 24 h postmortem. All fillets were sampled at time of deboning for expressible moisture, pH, R-value, gravimetric fragmentation index (GFI), and sarcomere length. The remainder of the fillet and the samples for GFI and sarcomere length were aged on ice until 24 h postmortem. After aging, fillets were analyzed for cook loss and shear value. Color was measured at time of deboning and at 24 h postmortem. Electrical stimulation accelerated rigor mortis development as indicated by significantly lower pH values and higher R-values at 2 h postmortem when compared to control fillets. The pH and R-values of the 2-h ES treatment were not significantly different from the 8-h ES, 8-h controls, or the 24-h controls. Fillets from carcasses that were ES and deboned at 2 h had significantly longer sarcomeres than the 2-h controls; however, there were no significant differences between the 2-h ES and the 8-h ES treatments, 8-h controls, or the 24-h controls. Although ES accelerated muscle metabolism at 2 h postmortem, it had no effect on shear value, expressible moisture, cook loss, GFI, L*, or a* color values. These results suggest that this postmortem ES system would not benefit turkey processors.

Fragmentation, tenderness, and post-mortem metabolism of early-harvested broiler breast fillets from carcasses treated with electrical stimulation and muscle tensioning

Two 72-bird trials were conducted to determine the effects of 15 s electrical stimulation (ES) (440 V, 2 s on and 1 s off) and prechill muscle tensioning (MT) on fragmentation, tenderness, and post-mortem metabolism of early-harvested (1 h post-mortem) broiler breast fillets. Compared with controls, all treatments increased sarcomere length and decreased shear value. Electrical stimulation reduced muscle pH values. Histological examination of samples from fillets harvested early and then aged 24 h revealed that all treatments increased fiber disruption compared with controls. Both fragmentation and excessive sarcomere shortening prevention were important to the improvement in fillet tenderness associated with the ES and MT treatments.