Characteristics of cold-induced dark, firm, dry broiler chicken breast meat

Abstract

1. A study was designed to characterise dark, firm, dry (DFD) breast meat resulting from cold exposure of broilers and compare its properties with normal breast meat from cold-stressed and control birds.

2. A total of 140 broilers were selected from 5- and 6-week-old birds exposed to cold temperatures ranging from −18 to −4°C, or a control temperature of +20°C for 3 h in an environmental chamber. Half of these birds were slaughtered immediately following the cold exposure and the other half were given 2 h of lairage.

3. Breast meat samples were categorised based on ultimate pH (pH_u) and colour L* (lightness) values into normal (5·7 ≤ pH_u ≤ 6·1; 46 ≤ L* ≤ 53) breast meat from control (control-normal) or cold-stressed (cold-normal) birds, and DFD (pH_u > 6·1; L* < 46) breast meat, which only occurred in cold-stressed birds (cold-DFD).

4. Residual glycogen was not different between cold-DFD and control-normal breast meat. Lactate concentration was lower in cold-DFD compared with control-normal breast meat. Lactate concentration almost tripled for all the samples by 30 h post-mortem, which resulted in a drop in pH of normal meat, but did not have any effect on pH of DFD breast meat. Glycolytic potential at both 5 min and 30 h post-mortem was lower in DFD breast meat compared with the normal breast meat from both cold-stressed and control birds.

5. Cold-DFD breast meat was significantly darker, with higher pH_u, lower cook loss, higher water-binding capacity and processing cook yield than cold-normal and control-normal breast meat, which were not different from each other.

Acknowledgements

The study was supported by funds provided by the Natural Science and Engineering Research Council (NSERC, Ottawa, Ontario, Canada), Agriculture and Agri-Food Canada (Ottawa, Ontario, Canada), Saskatchewan Chicken Industry Development Fund (Saskatoon, Saskatchewan, Canada), Alberta Farm Animal Care (Calgary, Alberta, Canada), Chicken Farmers of Saskatchewan (Saskatoon, Saskatchewan, Canada), Alberta Chicken Producers (Edmonton, Alberta, Canada), Poultry Industry Council (Guelph, Ontario, Canada) and Lilydale Foods Inc. (Edmonton, Alberta, Canada). Special thanks to management and staff of the Poultry Center at the University of Saskatchewan for their valuable support and participation throughout the study. Furthermore, technical assistance of Natasha Burlinguette with the Department of Agricultural and Bioresource Engineering, Tracy Leer Mercier with the Department of Animal and Poultry Sciences, and Heather Silcox and Derrick Pobereznek with the Department of Food and Bioproduct Sciences, University of Saskatchewan is greatly appreciated. In addition, editorial input of Dr Jon Watts with Poultry Transport Group at the University of Saskatchewan is greatly appreciated.