With the increasing demand for chicken cut-up products, rapid growth and breast muscle growth have become the primary selection criteria for the modern broiler industry. On the other hand, this has also brought about many abnormal meat quality problems, causing huge economic losses in the broiler industry worldwide. The abnormal broiler meat problems found so far mainly include deep pectoral myopathy, pale, soft, and exudative (PSE)-like meat, woody meat, white-striped meat and spaghetti shaped breast meat. Although progress has been made in the research on these problems, it has been uneven. Moreover, a systematic literature review on it is lacking, and there is little information about the utilization of abnormal broiler meat. This article summarizes recent progress in research on the abnormal broiler meat problems, and discusses the occurrence mechanism of these problems and their impact on meat quality. We hope that this article will provide a theoretical basis and technical help for relevant researchers and the broiler processing industry.

The effects of different degrees of woodiness (mild, moderate and severe) on the physicochemical properties and structure of chicken breast myosin were investigated. The results showed that the particle size and turbidity of myosin in wooden chicken breast muscle were increased compared with those in normal chicken breast muscle, reaching the highest values in severely wooden chicken breast muscle. The net negative charge loss and sulfhydryl group content decreased significantly with increasing degree of woodiness (P < 0.05), and the surface hydrophobicity increased significantly, reaching 747.57 ± 23.36 at a severe level of woodiness. Moreover, the occurrence of woodiness adversely affected the secondary structure stability of myosin, resulting in progressive conversion of α-helix to β-turn and random coil. The maximum endogenous fluorescence intensity of severely wooden myosin was higher than that of normal myosin (860.6 versus 505.1), indicating substantial exposure of tryptophan residues to the hydrophobic environment. In addition, the microscopic network structure of wooden chicken breast myosin was more disordered, and a large area of voids was formed when woodiness reached a severe level. Therefore, woodiness significantly affected the physicochemical properties of chicken breast myosin and higher degree of woodiness caused more serious structural deterioration.

To explore the oxidation mechanism of wooden breast myofibrillar protein (WBMP), oxidative breast MP (OBMP) was obtained from different doses (3, 10, and 20 mmol/L) of H₂O₂ oxidized normal breast MP (NBMP). The results showed that the Zeta-potential, particle size, solubility, sulfhydryl, and carbonyl contents of OBMP-3 (3 mmol/L, low-dose free radicals) and WBMP were similar. Fluorescence spectrum analysis showed that the oxidation of low-dose free radicals led to a significant increase in the surface hydrophobicity (from 214.03 ± 10.03 to 393.50 ± 10.33) and tryptophan fluorescence intensity (from 185.71 to 568.32). In addition, the α-helix content of WBMP decreased significantly from (37.46 ± 1.15)% (NBMP) to (34.70 ± 2.04)%, while β-sheet and random coil contents increased significantly (P < 0.05) from (14.37 ± 0.69)% and (22.24 ± 0.78)% (NBMP) to (17.70 ± 0.87)% and (25.20 ± 1.47)% (WBMP). In summary, low-dose free radical oxidation attacks protein groups, inducing secondary and tertiary structural changes, leading to the formation of WBMP. This work will provide a theoretical basis at the molecular level for exploring the mechanism of functional degradation of WBMP.

The deterioration of wooden breast myofibrillar protein (WBMP) increases with the increase in wooden breast grades. In order to quickly and conveniently classify wooden breast to prevent waste of raw materials and unsuitable processing. Different grades of wooden breasts that exhibited mild, moderate, and severe degrees were collected, and correlation analysis was employed for the quality and WBMP functional characteristic indicators. The indicators were further classified into two components according to the principal component analysis method. Based on the correlation and variation coefficients, two main indicators were selected to represent the quality level of wooden breasts (redness (a*) and pH value (P)). The weights of the two indicators were 0.353 and 0.219 for a* and P, respectively, using the weighted coefficient method. Therefore, a formula for calculating the comprehensive evaluation score (y) of different grades of wooden breast meat was obtained: y = 0.353a* + 0.219P. Based on regression analysis, the fitting equation y = 2.407 1x + 0.0343 (R² = 0.9883) was obtained, for the comprehensive quality score (y) and sensory evaluation score (x) through regression analysis, with a fitting coefficient ˃ 0.8. This equation can accurately predict sensory evaluation scores, effectively reflect the quality differences of different grades of wooden breasts, and accurately and rapidly grade wooden breasts.