EFFECT OF POSTMORTEM INJECTION TIME AND POSTINJECTION AGING TIME ON THE CALCIUM-ACTIVATED TENDERIZATION PROCESS IN BEEF

The objectives of this study were to determine 1) the effectiveness of calcium chloride when injected later than 2 d postmortem, 2) the effe ct of extended postinjection aging time, and 3) the tenderness respons e curve in calcium chloride-treated beef. In Exp. I, the longissimus t horacis et lumborum was injected on either d 2 or 14 postmortem with 5 % by weight of a 200 mM calcium chloride solution. Samples were aged ( 1 degrees C) either 7 or 35 d after injection. The uninjected control longissimus from the contralateral side was aged for 9, 21, 37, or 49 d. In Exp. 2, the longissimus thoracis et lumborum was injected on d 2 postmortem with 5% by weight of a 200 mxM calcium chloride solution t hen sampled for shear force on d 1, 2, 6, 8, 12, and 14 after injectio n. Calcium chloride injection, regardless of injection time or postinj ection aging time, had higher (P < .05) sensory tenderness rating than control with the same total aging time (5.2, 5.5, 5.8, and 6.1 vs 4.3 , 4.8, 5.1, and 5.3, respectively). Calcium chloride injection at d 14 reduced shear force (.7 kg) and increased tenderness rating (.7 units ) as effectively (P > .05) as injection at d 2 (1,2 kg and .8 units, r espectively). Calcium chloride-injected steaks had higher(P < .05) jui ciness ratings than control steaks. Postrigor calcium chloride injecti on reduced(P < .05) shear force within 1 d after injection and resulte d in more tender meat through 14 d after injection. Extended postinjec tion aging (35 d) had little effect on color display stability. Calciu m-activated tenderization can be applied as late as 14 d postmortem an d will reduce the occurrence of tough meat if aging is limited.