Rapid postmortem pH decline and delayed chilling reduce quality of turkey breast meat

Effects of rapid postmortem metabolism and delayed chilling on turkey breast meat quality were assessed using color measurements, protein extractability, and gelation characteristics. Based on 15 min postmortem breast muscle pH, tom turkey carcasses were classified as rapid glycolyzing (RG), pH < 5.80, or normal glycolyzing (NG), pH > 6.00. Two carcasses per group with similar ultimate pH values were selected on four occasions for a total of 16 carcasses. One half of each carcass was immersion-chilled at 20 min postmortem, the other half was maintained at body temperature for 110 min and then chilled. Breast meat from RG carcasses had higher carcass temperature (15 min) and lower protein (sarcoplasmic and myofibrillar) extractability than breast meat from NG carcasses. Delayed chilling increased all breast meat color values (L*, a*, b*), and decreased protein extractability and cook yield compared to breast meat from immediately chilled carcass halves. The true strain of cooked gels was reduced for RG carcasses. Delayed chilling reduced both true strain and stress of meat gels. There were no interactions between the rate of postmortem pH decline and initiation of chilling, indicating that reductions in meat quality due to delayed chilling were independent of the carcass classification for rate of postmortem glycolysis. Results indicate that factors that affect both rate of postmortem glycolysis and carcass temperature decline are important to turkey breast meat quality.