This review is a summary of a Poultry Science Association symposium addressing myopathies in broilers\' breast meat, focusing on the interactions between genetics, nutrition, husbandry, and meat processing. The Pectoralis major myopathies (woody breast [WB]; white striping [WS]; spaghetti meat [SM]) and Pectoralis minor (\"feathering\") are described, followed by discussing their prevalence, potential causes, current and future ways to mitigate, as well as detection methods (in live birds and meat) as well as ways to utilize affected meat. Overall, breast myopathies remain an important focus across the poultry industry and whilst a lot of data and knowledge has been gathered, it is clear that there is still a lot to understand. As there are multiple factors impacting the occurrence of breast myopathies, their reduction relies on a holistic approach. Ongoing balanced breeding strategies by poultry breeders is targeting the longer-term genetic component but comprehending the significant influence from nongenetic factors (short-term solutions such as nutrition) remains a key area of opportunity. Consequently, understanding the physiology and biological needs of the muscle through the life of the bird is critical to reduce the myopathies (e.g., minimizing oxidative stress) and gain more insight into their etiology.

Separating breast meat with low water-holding capacity, conformation parameters (thickness, volume, bottom sarea, and perimeter), and color of chicken breast meat were measured by direct measurement and by imaging analysis with a digital camera. Samples were obtained from a production line. The L* value was used to separate the samples by three characteristics designating the quality of the meat: dark-colored samples (L*<50), normal-colored samples (50≤L*≤56), and light-colored samples (L*>56). Light-colored samples had higher moisture content, thawing loss, drip loss, and lower pH compared with those of normal- and dark-colored samples. Lower thickness was observed in the light-colored samples compared with those of normal- and dark-colored samples. Light- and normal-colored samples had a greater volume of meat than did the dark-colored samples. Imaging analysis showed that light-colored samples had a greater bottom area and perimeter compared with those of normal- and dark-colored samples. However, these conformation parameters showed low correlation with water-holding capacity, which was determined as thawing and drip loss of the samples. Therefore, the conformation parameters, determined by direct measurement or imaging analysis, could not be used to predict the water-holding capacity of breast meat. Nevertheless, waterholding capacity showed high correlation with the L* value of breast meat. Imaging analysis could be used to separate light-colored breast meat with mostly low water-holding capacity. The accuracy of determining the characteristics of light-, normal-, and dark-colored samples by imaging analysis was evaluated. The characteristics of light-colored samples were determined with higher accuracy by imaging analysis than were the characteristics of normal- and dark-colored samples. This result indicated that imaging analysis using a digital camera could be used to separate light-colored breast meat with mostly low water-holding capacity from normal- and dark-colored meat.

Poultry meat is very susceptible to oxidation because of the high concentration of polyunsaturated fatty acids, which negatively affects the quality and nutritional values of chicken meat. Coccidiosis is the most common parasitic disease of poultry. Intending to limit anti-parasites usage in poultry feed and also because of the concerns about antibiotic resistance and residues in poultry products, there is a need for research to discover natural alternatives. The effect of nanocurcumin on antioxidant profile (carotenoid and vitamin E contents, lipid oxidation and antioxidant capacity) and pH of broiler chicken breast meat infected with Eimeria species was investigated. Fifty, one-day-old male Ross 308 broiler chickens were assigned to five treatments including non-infected and non-medicated control (NNC), infected non-supplemented control (INC), infected and medicated with nanocurcumin 300 mg kg-1 feed (NCRM1), infected and medicated with nanocurcumin 400 mg kg-1 feed (NCRM2) and infected and antibiotic medicated group. Infection with Eimeria acervulina, E. maxima, and E. tenella decreased vitamin E and carotenoid contents of chicken breast meat significantly. The NCRM2 had significantly enhanced carotenoid and vitamin E levels in chicken breast meat, so  there was no significant difference between NCRM2 and NNC group. No significant change was observed in pH value among groups. Malondialdehyde value of breast meat was significantly lower in NCRM1 and NCRM2 than the INC group. The NCRM2 and NCRM1 showed the best antioxidant capacity even better than NNC. In conclusion, nanocurcumin could be a potential feed additive that can increase oxidant stability of broiler chicken breast meat.

White striping (WS), an emerging muscle myopathy in poultry industry, is gaining increasing attention globally. In this study, visible and near-infrared hyperspectral imaging (HSI, 400-1000 nm) was investigated for developing an optical sensing technique to differentiate WS broiler breast fillets (pectoralis major) from normal fillets. The minimum noise fraction (MNF), followed by an inverse MNF (IMNF), was conducted to improve the signal-to-noise ratio of hyperspectral images during the pre-processing process. Three regions of interest (ROIs) were selected at cranial, middle and caudal locations within each fillet image. Spectral principal component analysis (PCA) revealed that PC2 and PC3 were effective for the differentiation and key wavelengths (450, 492, 541, 581, 629, 869 and 980 nm) were selected from the corresponding PC loadings. Spatial texture features on corresponding score images were obtained using gray level co-occurrence matrix (GLCM) and grayscale histogram statistics (GHS), respectively. Partial least squares discriminant analysis (PLS-DA) models were evaluated with various inputs including spectral (full and key wavelengths), textural and fused features. GLCM features improved performance of multispectral imaging with the highest correct classification rate (CCR) of 91.7%, AUC value (0.917), and Kappa coefficient (0.833) for prediction set. Considering the complexity and heterogeneity of meat samples at different locations, the optimal sampling location was also analyzed and results provided the evidence that the cranial location worked most effectively for the differentiation between normal and WS samples. Overall, results confirmed the great potential of HSI in range of 400-1000 nm in differentiation between normal and WS chicken breast meat.

Stunning method (low atmospheric pressure stunning, LAPS and electrical stunning, ES), deboning time (0.75 h and 4 h), and cooking method (baking, frying, and sous vide) were evaluated for their impact on the descriptive sensory characteristics and consumer acceptability of breast meat (n=576, 144 birds per stunning × deboning time combination). Sensory evaluation was conducted by trained descriptive (n=8) and consumer (n=185) panels. On average, no differences (P>0.05) existed in the sensory acceptability of fried and sous vide cooked broiler breast treatment combinations. However, for oven-baking, the LAPS treatment that was deboned at 4 h was more acceptable (P<0.05) than other treatments and the ES and LAPS 4 h samples had greater (P<0.05) acceptability for texture than their ES and LAPS 0.75 h counterparts. Since consumers were highly variable in their liking of chicken breast treatments, consumers were grouped into clusters for each cooking method based on liking and preference. Cluster analysis data revealed that the largest groups of consumers liked (score≥6.0) all chicken breast treatments, but a larger proportion of consumers liked the 4 h LAPS and ES treatments when compared to the 0.75 h LAPS and ES treatments for all cooking methods. In addition, the consumers who indicated that baked chicken breast was highly acceptable preferred (P<0.05) 4 h LAPS over the 4 h ES samples. Based on sensory results, chicken breast meat from all stunning and deboning method combinations was highly acceptable to the majority of consumers, but the LAPS 4 h treatment had enhanced sensory characteristics when baked.

The feasibility of using visible/near-infrared spectroscopy (vis/NIR) to segregate broiler breast fillets by water-holding capacity (WHC) was determined. Broiler breast fillets (n = 72) were selected from a commercial deboning line based on visual color assessment. Meat color (L*a*b*), pH (2 and 24 h), drip loss, and salt-induced water uptake were measured. Reflectance measurements were recorded from 400 to 2,500 nm in both raw and freeze-dried breast meat samples. Raw and freeze-dried samples had similar spectra in the visible region (400-750 nm), but the freeze-dried samples exhibited numerous bands in the NIR region (750-2,500 nm) corresponding to muscle proteins and lipids that were not observed in the NIR spectra of the raw samples. Linear discriminate analyses were used to classify fillets as high-WHC or low-WHC according to predicted meat quality characteristics. Using the visible spectra (400-750 nm), fillets could be correctly classified into high-WHC and low-WHC groups based on drip loss and salt-induced water uptake with 88 to 92% accuracy in raw samples and 79 to 86% accuracy in freeze-dried samples. Using the NIR spectra (750-2,500 nm), fillets could be correctly classified into high-WHC and low-WHC groups with 74 to 76% accuracy in raw samples and 85 to 86% accuracy in freeze-dried samples. Thus, freeze-drying enhanced the accuracy of WHC classification using the NIR portion of the spectra. Data from this study demonstrate the potential for utilizing vis/NIR spectroscopy as a method for classifying broiler breast meat according to WHC.

This study determined the effects of extraction buffer pH and postmortem aging on the extraction of salt-soluble and water-soluble proteins from broiler pectoralis muscle. Deboned broiler breast fillets were collected at 4 h postmortem, packaged, and then stored at 4°C until 1, 5, or 8 d postmortem. After the designated aging period, salt-soluble and water-soluble protein extractions were performed using buffers at 7 different pH levels (pH 5.4, 6.4, 6.9, 7.2, 7.5, 8.0, 9.0). Protein concentrations of the extracts were measured and SDS-PAGE analysis was performed. Salt-soluble protein concentration increased (P < 0.0001) as buffer pH increased from pH 5.4 to 6.9 and then remained unchanged from pH 6.9 to 9.0. Water-soluble protein concentration increased (P < 0.0001) as buffer pH increased from pH 5.4 to 7.2 and then remained unchanged from pH 7.2 to 9.0. There was not a significant extraction buffer pH by aging treatment interaction for the total protein concentration of either the salt-soluble or water-soluble protein extracts. The protein concentrations of salt-soluble extracts were similar at both 1 and 8 d postmortem but lower (P < 0.0001) at 5 d postmortem. The protein concentrations of water-soluble extracts were similar at both 1 and 5 d postmortem, but higher (P < 0.0001) at 8 d. Both extraction buffer pH and postmortem aging influenced the SDS-PAGE protein profiles of salt-soluble and water-soluble protein extracts from breast muscles. Data demonstrate that postmortem aging and extraction buffer pH influence both the total amount and the composition of the myofibrillar and sarcoplasmic proteins that can be extracted from broiler breast fillets.