INDUCED RED DISCOLORATION OF BROILER BREAST MEAT: II: EFFECT OF COOK TEMPERATURE AND FREEZING

Authors: Smith, Douglas; Northcutt, Julie

Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2004
Publication Date: 4/1/2004
Citation: Smith, D.P., Northcutt, J.K. 2004. Induced red discoloration of broiler breast meat: ii: effect of cook temperature and freezing. International Journal of Poultry Science. 3:253-258.

Interpretive Summary: Cooked chicken meat that is red or appears bloody is typically rejected by customers and consumers since it appears undercooked. Chicken products that contain bones (whole rotisserie chickens, fried, grilled or roasted chicken parts) have a low but consistent incidence of this red/bloody appearance. The problem is difficult to study in the laboratory or in the field because of the low incidence, yet only a few pieces or products can cause severe problems for the producer. This study was conducted to consistently induce a red and bloody appearance in fully-cooked chicken meat using bony marrow extracted from chicken bones, then to determine if increasing cooking temperatures or freezing before cooking would affect the amount of discoloration. Using the bony marrow did induce a very red and bloody appearance in chicken meat fully-cooked to 74 C (165 F), while higher temperatures (79 and 85 C) decreased red discoloration but not to an 'acceptable' appearance. Marrow frozen before cooking produced meat samples with less redness at the lower cooking temperatures, but still not to an acceptable level. Results show that fresh bony marrow effectively and consistently induces a red and bloody appearance in fully-cooked chicken in the laboratory and this model will be used for further studies on reducing this problem. Pre-freezing or cooking to higher temperatures reduced redness to an extent, but are not viable options as both procedures can impair meat quality and functionality.

Technical Abstract: Consumers and customers typically reject fully-cooked chicken that has a red/bloody appearance even if the product is otherwise safe and wholesome. Unfortunately, chicken parts and whole bird products may exhibit this problem on a consistent basis. This study was conducted to intentionally induce a red/bloody appearance in fully-cooked chicken to create a model for studying methods to control this defect. Five trials were conducted using bony marrow (harvested from the interior of epiphyseal end caps) from either fresh femurs (three trials) or frozen femurs (two trials) that were prepared and placed in contact with chopped broiler breast meat. Meat and marrow were packed into glass tubes and heated to one of three endpoint temperatures (74, 79, or 85 C). Five replicate tubes were prepared for each endpoint temperature in each trial (n=75). After cooking and immediate cooling, CIE lightness (L*) and redness (a*) was determined for both the surface of the meat adjacent to the bony marrow, and the surface of the marrow. The surface of the meat from samples prepared with fresh marrow were darker (lower L* values) and redder (higher a* values) than control meat surface samples. Each higher endpoint cook temperature resulted in a significantly (P<0.05) lighter and less red sample. The meat exposed to frozen marrow was affected by temperature to a lesser extent as lightness increased only at 79 C, and redness values did not significantly decrease from 79 C to 85 C. Lightness of the marrow surface was unaffected by freezing or endpoint cook temperature. Marrow surface redness was decreased as cook temperature increased, and freezing appeared to decrease the redness of samples cooked at either 74 or 79 C. Bony marrow was effective at inducing a red, bloody discoloration in breast meat samples. Higher cook temperatures and freezing femurs (before harvesting marrow) improved meat lightness and redness values, although not to control values.