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

Effects of rapid postmortem metabolism and delayed chilling on turkey breas t meat quality were assessed using color measurements, protein extractabili ty, and gelation characteristics. Based on 15 min postmortem breast muscle pH, tom turkey carcasses were classified as rapid glycolyzing (RG), pH less than or equal to 5.80, or normal glycolyzing (NG), pH > 6.00. Two carcasse s 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-chille d at 20 min postmortem, the other half was maintained at body temperature f or 110 min and then chilled. Breast meat from RG carcasses had higher carca ss temperature (15 min) and lower protein (sarcoplasmic and myofibrillar) e xtractability than breast meat from NG carcasses. Delayed chilling increase d all breast meat color values (L*, a*, b*), and decreased protein extracta bility and cook yield compared to breast meat from immediately chilled carc ass halves. The true strain of cooked gels was reduced for RG carcasses. De layed chilling reduced both true strain and stress of meat gels. There were no interactions between the rate of postmortem pH decline and initiation o f chilling, indicating that reductions in meat quality due to delayed chill ing were independent of the carcass classification for rate of postmortem g lycolysis. Results indicate that factors that affect both rate of postmorte m glycolysis and carcass temperature decline are important to turkey breast meat quality.