The Influence of Hot Boning Broiler Breast Muscle on pH Decline and Toughening

Abstract

Studies were conducted to determine the relationship of the postmortem pH decline of hot-boned broiler breast muscle (Pectoralis major) to the increased toughness often associated with hot boning. A total of 68 broilers were New York dressed, and trials were conducted to compare breast halves either hot boned at 0, 15, 30, 60, 120, or 240 min postmortem with the other (control) half allowed to remain on the carcass for 24 hr prior to removal. The pH values were taken on each bird at time of kill, time of excision on the excised or hot-boned muscle, and after 24 hr on both halves. Following a 24-hr ice chill, each muscle half was cooked at 100 C for 20 min, allowed to cool, and muscle tenderness determined using an Instron equipped with an Allo-Kramer shear cell. Results indicated that as postmortem pH values decreased, muscle toughness decreased with increased holding time prior to excision. Decreases in muscle pH values tended to level off at 5.9 after 4 hr or before, as did shear values of about 4.5 to 5.5 kg force/g sample. Thus, it appears that without the application of an effective accessory tenderizing treatment, muscle should be held for at least 4 hr postmortem prior to hot boning to avoid the adverse toughening effects commonly associated with hot-boned broiler breast meat.