Nutritional Strategies to Improve Meat Quality and Composition in the Challenging Conditions of Broiler Production: A Review.

Poultry meat is becoming one of the most important animal protein sources for human beings in terms of health benefits, cost, and production efficiency. Effective genetic selection and nutritional programs have dramatically increased meat yield and broiler production efficiency. However, modern practices in broiler production result in unfavorable meat quality and body composition due to a diverse range of challenging conditions, including bacterial and parasitic infection, heat stress, and the consumption of mycotoxin and oxidized oils. Numerous studies have demonstrated that appropriate nutritional interventions have improved the meat quality and body composition of broiler chickens. Modulating nutritional composition [e.g., energy and crude protein (CP) levels] and amino acids (AA) levels has altered the meat quality and body composition of broiler chickens. The supplementation of bioactive compounds, such as vitamins, probiotics, prebiotics, exogenous enzymes, plant polyphenol compounds, and organic acids, has improved meat quality and changed the body composition of broiler chickens.

An Investigation of the Altered Textural Property in Woody Breast Myopathy Using an Integrative Omics Approach.

Woody breast (WB) is a myopathy observed in broiler Pectoralis major (PM) characterized by its tough and rubbery texture with greater level of calcium content. The objective of this study was to investigate the functionality/integrity of WB sarcoplasmic reticulum (SR), which may contribute to the elevated calcium content observed in WB and other factors that may influence WB texture. Fourteen Ross line broiler PM [7 severe WB and 7 normal (N)] were selected, packaged, and frozen at -20°C at 8 h postmortem from a commercial processing plant. Samples were used to measure pH, sarcomere length, proteolysis, calpain activity, collagenase activity, collagen content, collagen crosslinks density, and connective tissue peak transitional temperature. Exudate was also collected from each sample to evaluate free calcium concentration. The SR fraction of the samples was separated and utilized for proteomic and lipidomic analysis. The WB PM had a higher pH, shorter sarcomeres, lower % of intact troponin-T, more autolyzed µ/m calpain, more activated collagenase, greater collagen content, greater mature collagen crosslinks density, and higher connective tissue peak transitional temperature than the N PM (p ≤ 0.05). Exudate from WB PM had higher levels of free calcium than those from N PM (p < 0.05). Proteomics data revealed an upregulation of calcium transport proteins and a downregulation of proteins responsible for calcium release (p < 0.05) in WB SR. Interestingly, there was an upregulation of phospholipase A2 (PLA2), and cholinesterase exhibited a 7.6-fold increase in WB SR (p < 0.01). Lipidomics data revealed WB SR had less relative % of phosphatidylcholine (PC) and more lysophosphatidylcholine (LPC; p < 0.05). The results indicated that upregulation of calcium transport proteins and downregulation of calcium-release proteins in WB SR may be the muscle's attempt to regulate this proposed excessive signaling of calcium release due to multiple factors, such as upregulation of PLA2 resulting in PC hydrolysis and presence of cholinesterase inhibitors in the system prolonging action potential. In addition, the textural abnormality of WB may be the combined effects of shorter sarcomere length and more collagen with greater crosslink density being deposited in the broiler PM.

Development of Imaging System for Online Detection of Chicken Meat with Wooden Breast Condition.

In recent years, the wooden breast condition has emerged as a major meat quality defect in the poultry industry worldwide. Broiler pectoralis major muscle with the wooden breast condition is characterized by hardness upon human palpation, which can lead to decrease in meat value or even reduced consumer acceptance. The current method of wooden breast detection involves a visual and/or tactile evaluation. In this paper, we present a sideview imaging system for online detection of chicken breast fillets affected by the wooden breast condition. The system can measure a physical deformation (bending) of an individual chicken-breast fillet through high-speed imaging at about 200 frames per second and custom image processing techniques. The developed image processing algorithm shows the over 95% classification performance in detecting wooden breast fillets.

Exploring the Factors Contributing to the High Ultimate pH of Broiler Pectoralis Major Muscles Affected by Wooden Breast Condition.

The elevated ultimate pH (pH u ) found in wooden breast (WB) meat suggests an altered muscular energetic status in WB but also could be related to a prematurely terminated post-mortem pH decline. The aims of this study were to explore the factors contributing to the elevated pH u and establish whether the occurrence of WB defect alters muscle post-mortem carbohydrate metabolism and determine if the contractile apparatus reflects such changes. A total of 24 carcasses from Ross 308 male chickens were obtained from a commercial producer and harvested using commercial processing procedures. Carcasses were categorized into unaffected (NORM) and WB groups (n = 12 each), and samples were collected from cranial bone-in pectoralis major (PM) muscles at 15 min and 24 h post-mortem for the determination of pH, glycolytic metabolites, adenonucleotides, buffering capacity, phosphofructokinase (PFK) activity, and in vitro pH decline. Twenty-four additional deboned PM samples (12 NORM and 12 WB) were collected from the same processing plant to assess muscle histology and sarcomere length at four different locations throughout the PM muscle. Data show that the reduced glycolytic potential of WB muscles only partially explains the higher (P < 0.001) pH u of WB meat, as residual glycogen along with unaltered PFK activity suggests that neither glycogen nor a deficiency of PFK is responsible for arresting glycolysis prematurely. The dramatic reduction in ATP concentrations in the early post-mortem period suggests a defective ATP-generating pathway that might be responsible for the reduced pH decline in WB samples. Further, the addition of excess of ATPase extended post-mortem glycolysis of WB meat in an in vitro glycolytic system. WB-affected samples have longer (P < 0.001) sarcomeres compared to NORM, indicating the existence of compromised energy-generating pathways in myopathic muscles that may have had consequences on the muscle contraction and tension development, as in vivo, also during the post-mortem period. Considering the overall reduced glycolytic potential and the myodegenerative processes associated with WB condition, we speculate that the higher pH u of WB meat might be the outcome of a drastically impaired energy-generating pathway combined with a deficiency and/or a dysfunction of muscle ATPases, having consequences also on muscle fiber contraction degree.

Effect of spaghetti meat abnormality on broiler chicken breast meat composition and technological quality.

The effects of spaghetti meat (SM) myopathy and sampling location on chicken breast meat physical traits, composition, and protein functionality were investigated using 30 normal (N) and 30 SM boneless fillets. Weight, drip loss, pH, and color traits were determined on intact fillets. Proximate composition, water holding capacity, mineral profile, SDS-PAGE, myofibrillar, and sarcoplasmic protein solubility, and emulsifying properties were assessed on both the superficial (S) and deep (D) layers of the breasts. SM fillets were heavier (P < 0.0001) and exhibited greater drip loss (P = 0.0131) and higher b* index on the skin side of the muscle (P < 0.0001). Muscle condition by layer interaction effect revealed that the superficial portion of SM fillets (SM-S) exhibited the highest moisture (P = 0.0003) and fat contents (P = 0.0011) coupled with the lowest protein (P < 0.0001) and ash contents (P = 0.0458). Total and soluble collagen amounts were higher in N-S and SM-S groups compared with N-D and SM-D (P < 0.0001). SM-S group exhibited the highest calcium (P = 0.0035) and sodium (P < 0.0001) levels. Overall, the myopathy had only minor impacts on protein profiles, while the muscle layer exerted a more remarkable effect. SM fillets exhibited higher pH but a lower myofibrillar protein solubility (P < 0.0001). Salt-induced water uptake, cooking loss, and final yield values suggested a potential impairment of water-holding capacity in SM-affected meat. Sarcoplasmic and myofibrillar emulsion activity indexes were similar between the 2 muscle conditions, but the stability of the emulsions was lower in SM meat. Overall, significant layer and muscle condition by layer effects were not observed in the functional properties of the breast meat. SM exerted a profound and negative impact on breast meat composition that led to detrimental consequences on functionality traits. Given the fundamental role of protein quality for meat processing, these data suggest that a further step toward the understanding of this myopathy should be the investigation of intrinsic protein characteristics.

In-Package Inactivation of Pathogenic and Spoilage Bacteria Associated with Poultry Using Dielectric Barrier Discharge-Cold Plasma Treatments.

The goal of this study was to test the efficacy of in-package dielectric barrier discharge-cold plasma (DBD-CP) treatment to inactivate poultry-associated spoilage (Pseudomonas fluorescens) and pathogenic (Salmonella enterica Typhimurium, Campylobacter jejuni) bacteria. Liquid cultures of the bacterial isolates were sealed within packages containing ambient air (Trial 1) or modified air (65% O2:30% CO2:5% N2; Trial 2). The packages were subjected to treatment times ranging from 30 to 180 s, and after 24 h incubation at 4 °C, bacterial titers were determined. The DBD-CP system completely inactivated the four isolates tested, although the in-package gas composition and treatment times were isolate-specific. Both C. jejuni isolates were completely inactivated between 30 s (modified air) and 120 s (ambient air), while modified air was required for the complete inactivation of S. typhimurium (90 s) and P. fluorescens (180 s). This DBD-CP system is effective for inactivating major poultry-associated spoilage and pathogenic bacteria in liquid culture, and through this study, system parameters to optimize inactivation were determined. This study demonstrates the potential for DBD-CP treatment to inactivate major bacteria of economic interest to the poultry industry, thus potentially allowing for reduced spoilage (e.g., longer shelf life) and increased safety of poultry products.

Measurement of muscle exudate protein composition as an indicator of beef tenderness.

UNLABELLED: The objective of this study was to determine the relationship between the protein composition of muscle exudates and meat tenderness in beef. Frozen, intact beef strip loins (n = 24) were each divided into 3 equal portions (anterior, middle, and posterior). Steaks were removed from each portion, individually vacuum packaged, thawed at 4 °C, and aged for 0, 7, or 14 d. After the designated aging period, exudate was collected from the packaging and 1 steak from each strip loin portion was utilized for shear force measurements. Muscle exudates were analyzed for protein content (biuret assay) and composition (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Shear force decreased (P < 0.0001) with aging from 0 to 14 d. The protein concentrations of the muscle exudates were not influenced by the aging period and were not related to the amount of exudate expressed. Electrophoretic analyses of the muscle exudates indicated that with aging the relative abundance of 4 proteins decreased (P < 0.01) and 10 proteins increased (P < 0.05) within the protein profiles of the exudates. The relative abundance of the 167, 97, and 47 kDa proteins in exudates at day 0 were significantly correlated (|r| = 0.57 to 0.77) to shear force at day 14. These data demonstrate that exudate protein composition changes with postmortem aging and beef tenderness. PRACTICAL APPLICATION: This research showed that the protein profiles of exudates that accumulate on the surface and in the packaging of beef change with meat aging and tenderness. These data suggest that muscle exudates may be a good source of protein markers that are useful in the development of rapid, noninvasive methodologies for predicting beef tenderness.

Effects of broiler carcass scalding and chilling methods on quality of early-deboned breast fillets.

The impact of scalding and chilling methods on quality of broiler breast fillets (pectoralis major) was evaluated. In 4 replications, 6- to 7-wk-old male and female broilers were slaughtered and scalded either at 60°C for 1.5 min (hard scalding) or 52.8°C for 3 min (soft scalding). Following evisceration, the carcasses were either air-chilled (0.5°C, 120 min) or immersion-chilled in water and ice (79 L/carcass, 0.5°C, 40 min, air agitated). Breast fillets were removed from the carcass within 4 h postmortem. Quality attributes including fillet color (both dorsal-bone and ventral-skin sides), pH, total moisture content, water-holding capacity (drip loss and cook loss), and Warner-Bratzler shear force were determined. Significant interactions between replication and scalding were found for pH, ventral side redness (a*) value, and cook loss and between replication and chilling for pH and ventral side a* and yellowness (b*) values. There were no interactions (P > 0.05) between chilling and scalding methods for any of the measurements. Immersion chilling resulted in higher (P < 0.05) ventral side lightness (L*) values, dorsal side b* values, drip loss, cook loss, and shear force compared with air chilling. No significant differences (P > 0.05) between the 2 scalding methods were observed for any of the quality attributes. These results indicate that broiler carcass chilling method has a much greater impact on quality of breast meat than scalding method and that the influence of chilling on breast meat quality is independent of scalding treatment.

Alterations in the sarcoplasmic protein fraction of beef muscle with postmortem aging and hydrodynamic pressure processing.

UNLABELLED: Capillary electrophoresis (CE) and reversed-phase high performance liquid chromatography (RP-HPLC) analyses were utilized to detect differences in the sarcoplasmic protein fractions of beef strip loins subjected to aging and hydrodynamic pressure processing (HDP) treatments. At 48 h postmortem, strip loins (n = 12) were halved and subjected to control or HDP treatments. Following treatment, each half was divided into 3 portions which were aged for 0, 5, and 8 d. After each aging period, steaks were removed for Warner-Bratzler shear force (WBSF) analysis and for the extraction of sarcoplasmic proteins which were analyzed by CE and RP-HPLC. Aging by HDP interactions were not detected using either separation technique. With CE analysis, no HDP effects were observed; however, the relative peak area of 8 protein peaks ranging in size from 17 to >200 kDa were influenced by postmortem aging. Separation of proteins by RP-HPLC demonstrated that HDP influenced the relative size of 2 protein peaks while postmortem aging effects were observed in 6 peaks. Alterations in the sarcoplasmic protein fractions detected by both CE and RP-HPLC were correlated to WBSF measurements. Overall, data demonstrate that HDP has minimal effects on sarcoplasmic proteins and that aging related changes in the water soluble protein fractions of muscle may be useful as indirect indicators of beef tenderness. PRACTICAL APPLICATION: Using 2 different postmortem tenderization techniques, aging and hydrodynamic pressure processing, this study demonstrates that postmortem changes in the soluble protein fraction of beef may be useful as potential indicators of meat tenderness.

Use of gelatin gels as a reference material for performance evaluation of meat shear force measurements.

UNLABELLED: Establishing standards for meat tenderness based on Warner-Bratzler shear force (WBSF) is complicated by the lack of methods for certifying WBSF testing among texture systems or laboratories. The objective of this study was to determine the suitability of using gelatin gels as reference materials for performance testing of texture measurement systems. Three replications of 5 gels (15%, 20%, 25%, 30%, and 35% gelatin) were prepared, vacuum packaged, and stored at 4 °C until use. Three randomly selected strips from each gel were subjected to WBSF testing on 4 instruments (A, B, C, or D) on days 1 and 8. Additional strips from each gel were subjected to WBSF testing on instruments A and C on day 29. Regression line estimates for each set of gels were analyzed. Gel WBSF values ranged from 10 to 177 N. The WBSF by gel concentration response was highly linear (P<0.0001) for all replications, instruments, and days of analysis. R2-values across all sets of gels ranged from 0.9562 to 0.9998. On days 1 and 8, instruments A and D exhibited higher slope (P<0.0001) and lower intercept (P<0.0001) estimates than instruments B and C. Regression line parameters (slope, intercept, and R2-values) were not influenced (P>0.05) by length of gel storage (1, 8, and 29 d). Data from this study suggest that gelatin gels can be used for evaluating WBSF values from various instruments and for validating the performance of meat shear force testing. PRACTICAL APPLICATION: Validating the performance of meat shear force testing is vital to establishing meat tenderness standards. The gelatin gel standards developed in this study exhibited a highly linear, repeatable relationship with shear force and were found to be stable for at least a month. These gel standards would provide a tool for the meat industry to harmonize shear force measurements across laboratories and various texture measuring instruments.

Effect of rapid thawing on the meat quality attributes of USDA select beef strip loin steaks.

The objective was to determine the meat quality effects of rapidly thawing beef steaks in a water bath. Frozen beef strip loins (n = 24) were cut into steaks sequentially from the rib end and identified by anatomical location (anterior, middle, posterior) within the loin. Within location, steaks were randomly assigned to conventional (C; 18 to 20 h, 4 °C) or rapid thawing methods. Rapid thawing methods, fast (20 min, 20 °C) or very fast (11 min, 39 °C), were conducted in a circulating water bath. The physical, thawing, cooking, color, and texture characteristics of each steak were recorded. Data were analyzed as a randomized complete block design with a 3 thawing treatments × 3 locations factorial analysis with loin as a block. No location by thawing method interaction was detected (P > 0.05) for the measured variables. Compared to C steaks, rapidly thawed steaks exhibited lower thaw drip loss (P < 0.001) and higher a* values (P < 0.001). Thawing treatment did not influence L*, b*, cook yield, or shear force. Steaks from the posterior end had higher (P < 0.001) surface to volume ratios that may have contributed to the higher thaw loss (P < 0.01), longer cooking time (P < 0.001), lower cooking yield (P < 0.001), and higher shear force (P < 0.02) compared to steaks from the anterior and middle portions of the loins. These data indicate that beef steaks taken from the entire length of the loin can be rapidly thawed in a water bath following food safety guidelines with minimal impact on meat quality. Practical Application: Freezing rate and frozen storage effects on meat quality have been well documented; however, there is comparatively little information on the meat quality effects of rapid thawing within food safety guidelines. This study demonstrates that beef strip loin steaks can be rapidly thawed in as few as 11 min without affecting texture or cooking yield, while reducing thaw drip loss. Thus, rapid thawing may enhance the apparent juiciness of steaks for consumers and provide an effective method for maintaining consistent control of experimental conditions for researchers.