Alternative slaughter procedures: on-farm slaughter and transport system for broilers.

This paper focuses on "alternative methods for initial broiler processing" and exploration of alternative processing including slaughter at the farm immediately after catching. On-farm slaughter and transport (FSaT) is envisioned as a mobile unit that stuns, slaughters, and shackles the broiler carcasses at the farm. A separate trailer-unit then transports the shackled broiler carcasses to the processing plant. Once at the processing plant carcasses are mechanically transferred into plant shackle lines and moved into processing. The hypothesis is that the FSaT approach will dramatically improve overall bird welfare and well-being by reducing live handling and eliminating live transport from the farm to the processing plant. In addition, ancillary impacts could include: improving yield efficiencies by eliminating dead on arrivals, potentially reducing water and energy consumption, reducing labor requirements at the processing plant with the elimination of live rehang, and offering an economically sustainable alternative. The FSaT approach represents a radical change from traditional processing, and its effects on poultry processing need to be evaluated. This paper presents results of experiments conducted at a commercial poultry processor to evaluate feather picking efficiency, carcass bacteriological loading, and meat quality for delayed processed carcasses.

Effect of meat temperature on moisture loss, water properties, and protein profiles of broiler pectoralis major with the woody breast condition.

The objective of this study was to investigate the influence of meat temperature on moisture loss, muscle water properties, and protein profiles in broiler pectoralis major with the severe woody breast (WB) condition. Broiler breast samples were collected from a commercial plant and sorted into normal, WB, and pale, soft, and exudative (PSE). Temperature treatments included 23°C, 40°C, 53°C, 57°C, 68°C, and 90°C based on denaturation of major muscle protein types during heating. Moisture loss was estimated with weight changes, water properties were measured with time-domain nuclear magnetic resonance measurements, and protein profiles were determined with SDS electrophoresis gel. There were no differences in moisture loss between 3 groups at meat temperature 23°C, 40°C, and 57°C. Moisture loss of WB samples was greater than normal and PSE at either 68°C or 90°C; however, it was the least at 53°C. Only close changing trend was noted between the intramyofibrillar water (T21) reduction and moisture loss. The extramyofibrillar (T22) water content and reduction in WB meat during heating were consistent greater, and electrophoretic profiles differed among 3 muscle conditions. Data suggest that greater reductions in intramyofibrillar and extramyofibrillar water are responsible for the increased moisture loss in WB meat at higher temperature.

Research Note: Comparison of 3 methods used for estimating cook loss in broiler breast meat.

The objective of this study was to evaluate different methods used for estimating cook loss in broiler breast fillets (pectoralis major). Two experiments were conducted. In the first experiment, intact fillets were weighed, cooked to 75°C, and then subjected to 1 of 3 postcook handling treatments: cooling for 5 min at room temperature before reweighing (5-minute), cooling at room temperature until they reached room temperature before reweighing (RT), or cooling in ice water until they reached room temperature before reweighing (IW). In the second experiment, breast fillet portions were used to compare the effects of endpoint temperature (53°C, 57°C, 68°C, 75°C, or 90°C) on cook loss estimation by the 5-minute and RT methods. Breast fillets were collected from local chicken processing plants and trimmed to similar weight prior to cooking. Cook loss, cook loss retention, and total cook loss after 24 h in cooked fillets were measured for comparisons. Data showed that cook loss (<17%) and total loss (19.3%) estimated with the IW method were lower (P < 0.05) than those with the 5-minute and RT methods (19-21% for cook loss and 21.1-21.3% for total loss), which did not differ from each other. When the endpoint temperature was ≥75°C, no differences in cook loss estimates or moisture loss were noted between the 5 min and RT methods (after 3 h cooling). However, when the temperatures were 53°C to 75°C, cook loss estimations were significantly different (P < 0.05) between the 5 min and RT methods (more than 4%). Reduced endpoint temperature resulted in increasing differences (from less than 5% to more than 9%) in cook loss estimates. These results demonstrate that endpoint cooking temperature and postcooking sample handling methods may affect cook loss estimates in broiler breast meat.

Muscle water properties in raw intact broiler breast fillets with the woody breast condition.

The purpose of this study was to investigate the relationships between muscle water properties, water-holding capacity (WHC), and woody breast (WB) severity in intact raw broiler breast fillets. Broiler pectoralis major deboned at 3 h postmortem was collected from a commercial plant and categorized as normal (NORM), moderate WB, or severe WB (SEV). Meat drip loss was calculated based on weight loss during overnight storage at 4°C. Water properties of the intact fillets were determined with time domain nuclear magnetic resonance and the T2 relaxation times were determined using an inverse Laplace algorithm (CONTIN). Three T2 water components, hydration water (T2b), intra-myofibrillar water (T21), and extra-myofibrillar water (T22), were identified. With increasing WB severity, the time constant of each water component and the relative content of T22 (P22) increased while the relative areas of T2b and T21 (P2b and P21, respectively) decreased. Spearman correlation analysis showed that there were significant correlations between the WB condition score and either the time constant or normalized area for each T2 component. T22 normalized areas (A22) were most strongly correlated with the WB score (r = 0.75); however, the weakest correlation was found between the WB score and T21 areas (A21). Pearson correlation analysis revealed that the strongest correlation (r = 0.64) was found between A22 and drip loss; however, there was no correlation between A21 and drip loss. Within the NORM group, drip loss was significantly correlated to the time constants for both T2b and T21. Within the SEV group, only A22 was significantly correlated to drip loss. These data indicate that the WB condition has a significant impact on the distribution of water within the intact muscle tissue. The content of extra-myofibrillar water in broiler breast fillets may be a key factor responsible for the poor WHC measurements in WB meat.

Relationships between instrumental texture measurements and subjective woody breast condition scores in raw broiler breast fillets.

The objective of this study was to compare the relationships between instrumental texture measurements and subjective woody breast (WB) scores in raw broiler breast fillets. A total of 181 broiler breast fillets were scored based on palpable hardness and rigidity ranging from 1.0 to 3.0 in 0.5 increments. Texture properties of raw fillets were measured with 3 different instrumental methods: compression force, blunt Meullenet-Owens Razor Shear (BMORS), and Meullenet-Owens Razor Shear (MORS). Compression force was measured based on % of fillet height (30%) and distance (10 mm). Blunt Meullenet-Owens Razor Shear and MORS measurements included peak force, energy, and peak counts. One-way ANOVA of instrumental texture measurements were performed. Spearman correlations between WB scores and instrumental texture measurements and Pearson correlations between 3 instrumental measurements were analyzed. ANOVA results showed that the best means separations between WB scores were found with the compression method. The weakest means separations were observed with MORS force and BMORS peak counts. Spearman correlation coefficients showed that there were significant relationships between WB scores and instrumental measurements. The strongest correlations were found between subjective WB scores and compression force measurements (r = 0.58-0.73, P < 0.0001), followed by BMORS force and energy (r = 0.55-0.56, P < 0 0.0001), MORS energy and peak count (r = 0.47-0.50, P < 0 0.0001), and BMORS peak count (r = -0.18, P = 0.015). The weakest correlation was found between the WB scores and MORS force (r = 0.17, P = 0.023). Pearson correlation coefficients between 3 different instrumental texture methods were also significant (P < 0.0001). These results demonstrate that there are significant correlations between subjective WB scores and instrumental texture measurements but that correlation strength varies with the instrumental method. Instrumental texture measurements can be used as references for subjective WB scores. Compression force method has the best potential for assessing subjective WB condition scores.

Detection of razor shear force differences in broiler breast meat due to the woody breast condition depends on measurement technique and meat state1.

Broiler breast meat with the woody breast (WB) myopathy exhibits abnormal tissue hardness and muscle rigidity in the raw state. The effectiveness of using instrumental shear measurements to characterize texture in WB fillets before and after cooking is not well understood. The objective of this study was to determine the influence of WB on razor shear force measurements in fresh never-frozen and frozen-thawed broiler breast fillets in both the raw and cooked state. Deboned breast fillets (n = 234) were collected from a commercial processing plant and categorized as normal (n = 78), moderate WB (n = 86), or severe WB (n = 70). At 24 h postmortem fillets were either used for texture analysis directly or frozen-thawed prior to analysis. Each fillet was measured before and after cooking using either the blunt blade (BMORS) or sharpened blade (MORS) versions of the Meullenet-Owens razor shear test. The ability of BMORS to distinguish between normal and WB fillets was different between raw and cooked fillets. In both fresh and frozen-thawed fillets, raw BMORS shear values (peak shear force and shear energy) increased (P < 0.0001) with WB severity. In fresh fillets, cooked BMORS values were similar between normal, moderate WB, and severe WB fillets. In frozen-thawed fillets, cooked BMORS values were greater (P < 0.001) in severe WB compared to normal fillets but were similar between normal and moderate WB fillets. Cooking had less impact on the ability of MORS to distinguish between normal and WB fillets. For both fresh and frozen-thawed fillets, MORS shear values (peak shear force and shear energy) were greater (P < 0.05) in WB fillets than normals in both the raw and cooked states. Data from this study demonstrate that the WB myopathy influences razor shear measurements in raw broiler breast fillets, but suggest that the ability to objectively detect texture differences in cooked WB meat is strongly dependent upon razor shear technique.

Use of blade tenderization to improve wooden breast meat texture2.

The effectiveness of blade tenderization (BT) in improving the texture of wooden breast (WB) meat was evaluated through compression and shear analyses. Butterfly fillets (n = 144) were collected during 3 sampling replications and scored as normal (NORM), moderate (WB MOD), or severe wooden breast (WB SEV). One side from each butterfly was blade tenderized and the other side served as an untreated control. Fillets were subjected to both compression and shear analyses in either the raw or cooked state. At 24 h postmortem, drip loss, pH, and color traits were assessed on raw fillets. Muscle condition (M), treatment (T), measurement location (L), and their interaction effects were investigated. WB fillets were heavier (P < 0.0001) and possessed greater pH (P < 0.0001) than NORM fillets. L*a*b* values on the skin side were increased in WB fillets (P < 0.0001), as were drip and cook loss (P < 0.0001). Irrespective of degree of severity, WB meat was harder as evidenced by greater compression force (P < 0.0001) in both raw and cooked fillets. Shear force of raw meat progressively increased from NORM to WB SEV (P < 0.0001) but there were no shear differences between NORM and WB MOD after cooking. Blade tenderization decreased compression and shear values in both raw and cooked WB fillets compared to untreated controls (P < 0.01). The significance of location effect for compression force (P < 0.0001) suggested that WB texture was not uniform within the same fillet. In raw fillets, an M × T interaction (P < 0.0001) was found for both compression and shear values and indicated that blade-tenderized WB MOD and WB SEV still possessed harder texture than NORM meat. However, the cooked shear values of WB SEV fillets subjected to BT were similar to those of untreated NORM fillets. Therefore, BT improved, but did not fully resolve the issues of abnormal tactile and texture characteristics in WB meat in either the raw or cooked state.

The wooden breast condition results in surface discoloration of cooked broiler pectoralis major.

Published studies have shown that the wooden breast (WB) condition affects the macroscopic appearance, quality, and functionality of raw broiler breast fillets (pectoralis major) as well as the texture of both raw and cooked fillets. In this study, we demonstrated for the first time that the WB condition also significantly affects the color and appearance of cooked breast fillets. Fresh broiler breast fillets (deboned at 3 h post-mortem) were collected from a commercial plant and sorted into normal (no WB) and severe WB condition categories based on palpable hardness and rigidity throughout the breast fillets. The fillets were either cooked directly from a fresh state, after marination with a target concentration of 0.75% NaCl and 0.45% phosphate at the end, or after storage at -20°C. Samples were cooked to 76°C in individual cooking bags in a combi-steam oven. Color measurements (CIEL*a*b*) on both the ventral and dorsal surfaces of cooked fillets were assessed using a Minolta spectrophotometer CM-700d. There were no significant CIE color value differences on the dorsal surfaces (bone side) of cooked fillets (P > 0.01). However, on the cooked ventral surfaces (skin side), the WB condition caused increases (P < 0.01) in a* and b* values and a decrease (P < 0.01) in the L* value regardless of marination treatment or frozen storage. The average L* values of cooked WB fillets were more than 6 units lower than in cooked normal fillets. After cooking, WB fillets showed higher a* and b* values by more than 0.5 and 2 units, respectively, than normal fillets. Data demonstrate that the WB condition can negatively influence the ventral surface color of cooked broiler breast fillets. The cooked surface of WB fillets was darker, redder, and more yellow than that of fillets without the WB condition. The detrimental effect of WB on the surface color and appearance of cooked breast fillets was noticeable and was not eliminated by marination or frozen storage.

Marination and cooking performance of portioned broiler breast fillets with the wooden breast condition.

The wooden breast (WB) condition in broiler breast meat negatively influences technological meat quality. However, it is unknown if the WB effects are uniform throughout the Pectoralis major. The objective of this study was to determine the effects of WB on the marination and cooking performance of the dorsal and ventral portions of broiler breast fillets. Sixty butterfly breast fillets were collected from the deboning line of a commercial plant and sorted into normal (no WB) and severe WB categories. Each fillet was horizontally portioned into dorsal and ventral halves. Portions from one side of each butterfly were used as non-marinated controls, while portions from the other side were vacuum-tumble marinated (16 rpm, -0.6 atm, 4°C, 20 min) with 20% (wt/wt) marinade to meat ratio. Marinade was formulated to target a final concentration of 0.75% salt and 0.45% sodium tripolyphosphate in the final product. Samples were cooked to 78°C in a combination oven. Marinade uptake and retention were lower (P < 0.001) in both the ventral and dorsal portions of the WB fillets. The dorsal portions had greater (P < 0.001) marinade uptake and retention than the ventral portions in both normal and WB fillets. For non-marinated samples, cook loss was greater (P < 0.05) in both the ventral and dorsal portions of WB fillets. In marinated samples, however, cook loss was similar between the dorsal portions of normal and WB fillets. Final cooked product yield was calculated based on pre-marination and post-cook weights. Non-marinated WB samples exhibited lower (P < 0.001) cooked product yields than normal samples in both portions. For marinated samples, cooked product yields were greater (P < 0.001) in the dorsal portions. Data demonstrated that the dorsal portion of the Pectoralis major more readily absorbs and retains marinade during vacuum tumbling and storage than the ventral portion. Although the WB condition negatively influenced marination and cooking performance in both fillet portions, the effects were less severe in the dorsal portion.

Descriptive sensory analysis of marinated and non-marinated wooden breast fillet portions.

The wooden breast (WB) myopathy influences muscle composition and texture characteristics in broiler breast meat. It is unknown if marination reduces the negative influence of WB on meat sensory quality or if WB effects are uniform throughout the Pectoralis major. The objective of this study was to determine the effects of marination on the sensory attributes and instrumental shear force measurements of the ventral (skin-side) and dorsal (bone-side) portions of normal and severe WB meat. Sixty butterfly fillets (30 normal and 30 severe WB) were selected from the deboning line of a commercial processing plant. Individual fillets were portioned into ventral and dorsal halves. Portions from one side of each butterfly were used as non-marinated controls, and portions from the other side were vacuum-tumble marinated (16 rpm, -0.6 atm, 4°C, 20 min) with 20% (wt/wt) marinade to meat ratio. Marinade was formulated to target a concentration of 0.75% (w/v) salt and 0.45% (w/v) sodium tripolyphosphate in the final product. Descriptive sensory analysis (9 trained panelists) was conducted to evaluate visual, texture, and flavor attributes (0-15 point scale) of breast portions along with Warner-Bratzler shear force. Significant interaction effects between WB and marination were not observed for the sensory attributes. Greater springiness, cohesiveness, hardness, fibrousness, and chewiness scores were observed in WB samples (P < 0.001). Marination decreased cohesiveness, hardness, and chewiness (P < 0.05) and increased juiciness (P = 0.002). The effects of WB on sensory texture attributes were more apparent in the ventral portions of the breast fillets. Flavor attributes (salty and brothy) increased (P < 0.001) with marination. In non-marinated samples, shear force was similar between normal and WB samples. In marinated samples, however, shear force was greater (P < 0.001) in WB samples. Data suggest that the WB effect on meat sensory quality is not uniform throughout the Pectoralis major and that WB-related differences in cooked meat sensory texture attributes are lessened but not eliminated by vacuum-tumbling marination.

Descriptive texture analyses of broiler breast fillets with the wooden breast condition stored at 4°C and -20°C.

The objective of this study was to evaluate the effects of the wooden breast (WB) condition on the texture of cooked broiler breast fillets (Pectoralis major) after fresh and frozen storage. Texture characteristics of normal (NORM) and severe WB fillets were studied by both sensory descriptive analyses and Warner-Bratzler shear force. Broiler breast fillets were collected over 3 separate trial days from a commercial deboning line at 3 h postmortem, classified according to the wooden breast condition, and then stored at either 4°C or -20°C prior to cooking and texture evaluation. Fillets were cooked to an endpoint temperature of 76°C and then evaluated by an 8-member trained sensory panel for springiness, cohesiveness, hardness, juiciness, cohesiveness of mass, bolus size, wetness of mass, fibrous texture, rate of breakdown, and chewiness. The fillets with the WB condition showed higher cook loss than those with NORM condition regardless of storage temperature. The mean value of shear force of WB fillets was lower than NORM fillets when cooked after 4°C storage. Sensory evaluation showed that WB fillets were higher in springiness and cohesiveness than NORM fillets and that the sensory attributes springiness, hardness and fibrousness were perceived differently between ventral and dorsal sections of cooked WB fillets. This work indicates that human perception of cooked WB meat has texture irregularities. The cooked breast meat with the WB condition is perceived with more springiness and cohesiveness than that with no WB condition.

Impact of alternative electrical stunning parameters on the ability of broilers to recover consciousness and meat quality.

Broilers in the United States are typically electrically stunned using low voltage-high frequency (12-38 V, ≥400 Hz) DC or AC water bath stunners. In the European Union, however, broilers are required to be electrocuted using high voltage-low frequency (50-150 V, 50-350 Hz) AC. Low voltage stunned broilers regain consciousness in the absence of bleeding. In contrast, high voltage stunned broilers die due to induction of cardiac fibrillation. For birds stunned with low voltage systems, concerns have been raised regarding animal welfare during bleeding. This work evaluated the impact of extended DC stunning duration and alternative stunning methods (DC+AC combination) on the recovery of bird consciousness and meat quality. In the absence of bleeding, broilers that were DC stunned for extended times (60, 90, or 120 s), 63, 10, or 0% of broilers, respectively, were able to recover consciousness. Alternative stunning protocols included water bath stunning broilers at 15 or 25 V DC for 10 s followed by plate stunning at 100, 110, or 120 V AC for 5 s. Prior to shackling, live body weight and shank width were measured and during stunning, maximum mA for both DC and AC stuns were recorded. All of the alternative stunning protocols (DC+AC) resulted in non-recoverable stunning. The maximum mA recorded during both DC and AC stunning were moderately/strongly (r = 0.54-0.81) correlated to body weight and poorly/moderately (r = 0.27-0.74) correlated to shank width. No significant differences for carcass or meat quality characteristics (hemorrhages, red wing tips, broken clavicles, pH, cook loss, a* and b* color values, and MORS shear energy) were detected between control (15 or 25 V DC only) and treatment groups (DC+AC combination stunning). The only significant different meat quality parameter was L* values where the lowest voltage group (15 V DC) had the darkest fillets (53.27) and the 15 V DC+100 V AC group had the lightest fillets (55.61) with all other groups intermediate. These data indicate that stunning parameters combining DC and AC stunning may be viable protocols when a stun-to-death is desired.

Freezing-thawing and sub-sampling influence the marination performance of chicken breast meat.

Vacuum-tumbling marination is often used to improve the yield and quality of whole or portioned broiler breast fillets. The relationship between the marination performance of whole Pectoralis major muscles and breast fillet sub-samples is not well understood. The objective was to determine the effects of sub-sampling and freezing-thawing on the marination performance and cook loss of broiler breast meat. Paired right and left breast fillets were marinated as whole fillets or sub-samples (cranial and mid-caudal portions). Samples were marinated at 48 h postmortem (fresh) or stored at -20°C and then thawed prior to marination (frozen-thawed). Samples were vacuum-tumbled in 20% wt/wt brine (5% NaCl, 3% STP) and weighed pre-marination, during marination (15, 30, and 45 min), and 24 h post-marination. Samples were then cooked to 75°C for determination of cook loss. Marinade uptake was greater in caudal sub-samples than intact fillets and cranial sub-samples after 15 min of marination (P < 0.0001). After 30 min, marinade uptake was greater in caudal sub-samples and intact fillets than cranial sub-samples (P < 0.05). After 45 min, marinade uptake for fresh samples was greatest in intact fillets and lowest in cranial sub-samples. For frozen-thawed samples, marinade uptake at 45 min was greater in caudal sub-samples and intact fillets than cranial sub-samples (P < 0.0001). Marinade uptake in sub-samples at 30 min was greater in frozen-thawed versus fresh fillets (P < 0.05). Differences in marinade retention were not observed. Cook loss was similar between fresh and frozen-thawed samples but was greater in sub-samples compared to intact fillets (P < 0.0001). Correlations between marinade uptake in intact fillets and cranial sub-samples were greater in fresh (r = 0.64 to 0.78) than frozen-thawed samples (r = 0.39 to 0.59). Correlations between marinade uptake in intact fillets and caudal sub-samples were greater in frozen-thawed (r = 0.79 to 0.82) than fresh samples (r = 0.46 to 0.63). Data suggest that the relationships between marination performance of whole breast fillets and fillet sub-samples are dependent upon prior sample handling and intra-fillet sampling location.

Descriptive texture analyses of cooked patties made of chicken breast with the woody breast condition.

The woody breast (WB) condition negatively influences the texture characteristics and quality of intact broiler breast fillets (Pectoralis major). But the impact of WB on ground meat is unknown. The objective of this study was to evaluate the effects of WB on the texture and cook loss of ground meat made of broiler breast fillets. Broiler breasts (deboned 3 h postmortem) were collected on 3 separate trial d from the commercial deboning line and classified into normal and severe WB fillet categories. Individual fillets were either ground and formed into patties or left intact prior to being stored for 7 d at -20°C. Samples were then cooked directly from the frozen state to an endpoint temperature of 76 °C for cook loss, instrumental (patties: Allo-Kramer shear; fillets: Warner-Bratzler shear), and descriptive sensory analysis of texture. Cook loss was greater (P < 0.05) in intact WB fillets compared to that in intact normal fillets, but there was no difference (P > 0.05) between WB and normal patties. There was no difference (P > 0.05) in shear force between normal and WB samples regardless of meat type. Sensory analysis showed that average scores of springiness and hardness of intact WB fillets were greater than those of normal fillets (P < 0.05). However, there were no significant differences (P > 0.05) in average scores for sensory attributes cohesiveness, hardness, juiciness, fibrous, and rate of breakdown between WB and normal patties. WB patties exhibited lower springiness and chewiness scores (P < 0.05) than normal patties. Data suggest that undesirable differences in sensory texture characteristics between cooked intact WB and normal breast meat can be minimized in a ground product.

Instrumental texture characteristics of broiler pectoralis major with the wooden breast condition.

The objective was to characterize texture properties of raw and cooked broiler fillets (Pectoralis major) with the wooden breast condition (WBC) using the instrumental texture techniques of Meullenet-Owens Razor Shear (MORS) and Texture Profile Analysis (TPA). Deboned (3 h postmortem) broiler fillets were collected from a commercial plant and categorized as normal, moderate, or severe WBC based on the incidence and severity of diffuse hardened areas throughout fillets and the degree of palpable hardness. The fillets were then either stored at 4°C overnight or in a -20°C freezer. The MORS and TPA of the raw samples were determined at 24 h postmortem for fresh samples and after thawing overnight for frozen samples. The same measurements were also taken after the samples were cooked to 78°C. Regardless of freshness (fresh vs. frozen-thawed), cooking (raw vs. cooked), and degree of WBC, both MORS force and energy of the WBC samples were higher than that of the normal samples (P < 0.05). For TPA adhesiveness and resilience, there were no differences between normal and WBC samples (P > 0.05). However, average TPA hardness and chewiness measurements of the fillets with WBC were higher than the normal fillets (P < 0.05). Regardless of texture measurement, there were no interactions between freshness and the wooden condition or no differences between moderate and severe WBC fillets (P > 0.05). These results demonstrate that there are significant differences in instrumental texture properties between normal fillets and those exhibiting the WBC. The WBC fillets required more force to cut through, harder, and chewier than normal breast muscles. These results suggest that cooked WBC meat would likely be tougher than cooked normal meat.

Comparison of sensory texture attributes of broiler breast fillets with different degrees of white striping.

The white striping (WS) condition in broiler meat results in increased intramuscular fat, connective tissue, and moisture loss during cooking and negatively affects product appearance and consumer acceptance of skinless chicken meat. The effect of WS on the human perception of cooked meat texture is unknown. The objective of this study was to evaluate the effects of WS on sensory texture attributes of cooked chicken breast fillets (Pectoralis major). Over three separate trial days, a total of 105 breast butterfly fillets were collected from the deboning line of a commercial broiler processing plant. Fillets were classified according to the degree of WS (normal, moderate, severe) and stored at -20°C until use. Fourteen representative fillets from each category were cooked directly from the frozen state to an endpoint temperature of 78°C and evaluated by a 7-member trained panel for five texture attributes: cohesiveness, hardness, juiciness, rate of breakdown, and chewiness. There were no differences (P > 0.05) for juiciness or the rate of breakdown between the fillets based on the degree of WS. Among the three WS groups, however, differences (P < 0.05) in cohesiveness, hardness, and chewiness were observed. For these attributes, the mean intensity scores of fillets with severe WS were consistently highest among the groups. There were no differences (P > 0.05) between the normal and moderate WS fillets. These data suggest that the severe WS condition was perceived to be harder, more cohesive, and chewier than either normal or moderate WS fillets by panelists.

Impact of white striping on functionality attributes of broiler breast meat1.

The influence of white striping (WS) on the water-holding capacity (WHC) and protein functionality attributes of broiler breast meat was investigated. Boneless breast fillets (Pectoralis major) were collected from the deboning line of a commercial processing plant and categorized by WS score (normal, moderate, severe). The physical (weight, pH, CIE-color values), water-holding capacity (salt-induced water uptake, cook loss, final yield), protein functionality (solubility, emulsifying activity), and protein composition (SDS-PAGE) characteristics of the fillets were measured in three experiments. Breast meat with WS exhibited greater fillet weights, higher pH, and similar color values (L*a*b*) to normal fillets. In experiment 1, fillets were frozen-thawed prior to analysis. The WS condition reduced thaw loss, sarcoplasmic protein solubility, and the emulsifying activity of the myofibrillar proteins, but did not significantly affect salt-induced water uptake, cook loss, final yield, or myofibrillar protein solubility. In experiment 2, breast meat was analyzed fresh and after a freeze-thaw cycle. Freezing samples prior to analysis negatively influenced WHC and reduced sarcoplasmic protein solubility in both WS and normal fillets. In fresh and frozen-thawed meat, the WS condition decreased sarcoplasmic protein solubility but did not significantly alter WHC or myofibrillar protein solubility. For experiment 3, fillets were portioned into 3 sections (Location A, cranial end-ventral surface; Location B, cranial end-dorsal surface; Location C, caudal end). The effects of WS on WHC and protein solubility were dependent upon breast fillet sampling location. Fillets with WS exhibited lower salt-induced water uptake, greater cook loss, and lower sarcoplasmic protein solubility than normal fillets when sampled from location A. SDS-PAGE analysis indicated that differences in the composition of sarcoplasmic and myofibrillar protein fractions between WS and normal fillets were influenced by sampling location. These results suggest that WS diminishes the WHC and protein functionality of broiler breast meat, but demonstrate that the WS effects on these traits are not uniform throughout the breast muscle.

Exudate Protein Composition and Meat Tenderness of Broiler Breast Fillets.

The relationship between meat tenderness and the protein composition of muscle exudates collected from broiler breast fillets deboned at different postmortem times was investigated. A total of 85 broilers were processed and breast fillets from each carcass were deboned at either 2 h (early-deboned, EB) or 24 h (control) postmortem. One fillet per carcass was used for 1 d postmortem meat tenderness measurements and the other fillet was stored at 4°C until 6 d postmortem for the collection of exudate prior to tenderness evaluation. Protein content and composition of muscle exudates were determined by a biuret assay and SDS-PAGE. Fillet pH, color, drip loss, and cook loss were also measured. Early-deboned fillets exhibited greater (P < 0.05) Warner-Bratzler shear force (WBSF) than controls at 1 d (7.4 vs. 3.1 kg) and 6 d (4.1 vs. 2.5 kg). Deboning time did not influence pH or color values (L*a*b*). Control fillets exhibited less drip loss after 6 d of storage (P = 0.005) and less cook loss at 1 and 6 d (P < 0.001). Exudate protein concentration was not influenced by deboning time. From the SDS-PAGE profiles of the exudates, the relative abundances of seventeen protein bands were quantified. Electrophoresis analysis revealed that, in general, the protein profiles of exudates from control and EB fillets were not distinct from each other. However, the band corresponding to 225 kDa was more abundant in controls (P = 0.021). Although the protein concentrations and SDS-PAGE profiles of muscle exudates varied widely between breast fillets, variations in exudate protein characteristics were not strongly associated with changes in the tenderness of broiler breast meat due to the combined effects of postmortem deboning time and post-deboning aging.

Relationship between water-holding capacity and protein denaturation in broiler breast meat.

The objective of this study was to determine the relationship between water-holding capacity (WHC) attributes and protein denaturation in broiler breast meat. Boneless skinless breast fillets (n = 72) were collected from a commercial processing plant at 2 h postmortem and segregated into low-WHC and high-WHC groups based on muscle pH and color (L*a*b*). At 6 and 24 h postmortem, brine uptake (%), cooking loss (%), and protein solubility (sarcoplasmic and myofibrillar) were measured and protein fractions were analyzed using SDS-PAGE. Drip loss accumulation (%) was measured after storage for 2 and 7 days postmortem. High-WHC fillets exhibited lower L*-lightness values and greater pH values at 2 and 24 h postmortem than low-WHC fillets. High-WHC fillets had greater brine uptake and less cooking loss at both 6 and 24 h postmortem compared to low-WHC fillets. Aging from 6 to 24 h postmortem increased brine uptake in high-WHC fillets, but did not affect cooking loss in either low-WHC or high-WHC fillets. Drip loss accumulation was greater in low-WHC fillets at both 2 and 7 days postmortem. Myofibrillar protein solubility decreased with postmortem time but was not different between low-WHC and high-WHC fillets. Sarcoplasmic protein solubility increased with postmortem time and was greater in high-WHC fillets. SDS-PAGE analysis indicated that low-WHC fillets exhibited more glycogen phosphorylase denaturation than high-WHC fillets as evidenced by a more extensive shift of the protein from the sarcoplasmic to the myofibrillar protein fraction. Correlation analysis revealed that overall protein solubility measurements were not related to WHC attributes but that the degree of glycogen phosphorylase denaturation was significantly correlated (|r| = 0.52 to 0.80) to measures of WHC. Data indicated that WHC differences in broiler breast fillets were not due to differences in myofibrillar protein denaturation and suggested that the denaturation of sarcoplasmic proteins onto myofibrils may influence WHC in breast meat.

Effect of postmortem aging on marination performance of broiler breast pectoralis major categorized by color lightness.

The objective was to evaluate the effect of postmortem aging on marination performance of early-deboned chicken breast fillets (pectoralis major) with different color lightness. Effects of marination on muscle shear force were also determined. Early-deboned (2 h postmortem) broiler butterfly fillets were visually selected based on their color lightness (pale, normal, and dark) from a commercial plant. The individual butterfly fillets were separated into left and right fillets. One of them was used for 6-h marination treatment and the other for 24-h marination treatment. Samples were marinated in a vacuum tumbler (-0.6 atm, 16 rpm, 20 min) with 20% wt/wt marinade yielding 0.75% NaCl and 0.45% phosphate in the final product. The effect of aging on salt-induced water gain by breast muscle was also measured using the swelling/centrifuging method. Marinade uptake, marinade retention, raw product yield, and cooked product yield were determined after tumbling, following storage for 24 and 48 h after marination and after cooking. Salt-induced water gain was greater (P < 0.05) in nonmarinated fillets at 24 h postmortem compared with 6 h postmortem. Compared with unmarinated fillets, marination enhanced finished product yield significantly (P < 0.05) regardless of postmortem aging and color lightness. Marinade retention and product yield were different (P < 0.05) in fillets categorized by L* (lightness) values. There were no differences (P > 0.05) between 2 postmortem aging times for marinade uptake, overall product yield, cooking loss, final cooked product yield, or meat shear force regardless of initial fillet L* values. However, marinade retention of 6-h samples was significantly better than 24-h samples (P < 0.05). These results demonstrate that with a targeted 15% marinade uptake, postmortem aging of 2-h deboned fillets before marination does not affect marinade uptake and product yield, but significantly affects marinade retention by boneless skinless chicken breast.