Quality parameters of chicken breast meat affected by carcass scalding conditions.

OBJECTIVE: The influence of broiler carcass scalding conditions on chicken breast meat quality parameters was investigated. METHODS: Two hundred and seventy Cobb broiler chickens from 42 to 48 days old were slaughtered according to the standard industry practice and scalded in five temperature/time combinations-T1, 54°C/210 s; T2, 55°C/180 s; T3, 56°C/150 s; T4, 57°C/120 s; T5, 58°C/90 s. RESULTS: Scalding temperature increase resulted in higher values of external and ventral lightness and in protein functionality reduction-determined by emulsification capacity and protein denaturation-in chicken breast fillets 24 h post-mortem. Protein secondary structures had conformational changes, with a decrease of the α-helix and an increase of the ß-sheet and ß-turn proportions, mainly in T1 and T5 samples, determined by Fourier-transform infrared spectroscopy in an attenuated reflectance mode analysis. The chemical composition, pH, water holding capacity and Warner-Bratzler shear force did not differ among the treatments. In the fatty acid profile, the 18:1n-9 was lower in T5, which suggested that the high scalding-temperature could have caused the lipid oxidation. The values of the polyunsaturated fatty acids (PUFA), such as 22:2, 20:4n-6, and 22:6n-3, were highest in the T5, thus being related to the phospholipid cellular membrane collapse in this experimental condition and subsequent release of these PUFA. CONCLUSION: Intermediate scalding-parameters avoided the negative changes in the chicken meat quality.

Physicochemical and biochemical parameters of chicken breast meat influenced by stunning methods.

The influence of stunning methods on the physicochemical and biochemical parameters of chicken breast meat, as indicators of bird stress, was investigated. A total of 200 Cobb broiler chickens aged from 42 to 48 d were submitted to gas or electrical stunning and slaughtered according to the standard industry practice. Pectoralis major muscles (24 h post-mortem) from broilers stunned by electronarcosis exhibited a higher L* and R-value and lower pH45min than did those from gas stunning, indicating modification of the glycolytic rate. Protease activity, measured as the myofibril fragmentation index, and the sarcoplasmic Ca2+ concentration were highest in samples from broilers stunned by electronarcosis, suggesting the greatest activity of the calpain system. In the fatty acid profile, a higher ratio of polyunsaturated fatty acids was observed in samples from broilers stunned by electronarcosis. These characteristics are related to phospholipase A2 activity, which is higher in animal stress conditions. These results indicated that the gas-stunning method produced less bird stress than electrical stunning.