POSTMORTEM DELAY-TIME AND HEATING RATE AFFECT TENDERNESS AND ULTRASTRUCTURE OF PRERIGOR COOKED BOVINE MUSCLE

The response of prerigor bovine muscle to different heating conditions was determined. Samples were fast-heated at six postmortem times or a t five heating rates at four early postmortem times. All samples were heated to 70 degrees C internally. Prerigor muscle cooked at progressi vely shorter postmortem times and faster heating rates had correspondi ngly lower shear values. In prerigor fast-heated samples, phase contra st microscopy revealed transverse bright stripes along the myofiber wh ile scanning electron microscopy showed transverse surface wrinkles, b ulges, interior contraction bands, and stretched areas. Postmortem tim e and heating should be controlled to improve beef tenderness.