Effect of heat stress and holding time ante-mortem on the physicochemical and quality characteristics of chicken meat

The effect of heat stress and holding time was evaluated before slaughter in the development of rigor mortis and physicochemical characteristics of meat in chicken Pectoralis major. The treatments were: two and eight hour holding before slaughter at temperature 24 degrees C (2HE24C, 8HE24C) and two hours holding before slaughter at 40 degrees C (2HE40C). For the rigor mortis development were measured the pH, color indices L*, a* and b* at 0.25, 1, 2, 4, 8, 24, 48, 96 and 144 h in 90 chickens. For the physicochemical characteristics, and other 90 chickens were slaughtered and the pH, color, water holding capacity (WHC), drip lost (DL), shear force (SF) and cook yield (CY) in meat were measured at 24 hours post mortem. The pH and indices measured color over time showed differences between treatments (P < 0.05). The physicochemical characteristics showed differences between treatment (P < 0.05) with a higher DL, lower WHC and PC, harder texture, low pH and rates of L* and b* being high for the meat of 2HE40C, while the opposite happened with the meat of 8HE24C. When broilers are subjected to heat stress conditions, a pale, soft, and exudative (PSE) meat is obtained, and long waiting induces dark, firm, and dry (DFD) meat. The holding time prior to slaughter of 2 h at room temperature does not adversely affect the quality of the meat.