TENDERNESS AND RELATED ORGANOLEPTIC CHARACTERISTICS OF BEEF CARCASS AS AFFECTED BY POSTMORTEM CHILLING TEMPERATURE

Abstract

Sides of beef from 27 carcasses (a total of 54) were selected on the basis of size and age, 40 min post-slaughter, and subjected to one of two treatments. Right sides were chilled at a slower rate (7–8 C ambient temperature), while the left sides were chilled according to standard packing house procedure (1 C ambient temperature) for the first 24 h. The rate of carcass temperature decline and the change in muscle pH was monitored every 4 h for the first 24 h and again at 48 h and 72 h post-mortem. Sides were graded individually for color, texture and marbling. Steak samples were subjected to shear tests, organoleptic testing by a trained panel, standard chemical analysis and a physical measurement of water-binding ability (expressible juice). The pH declined more rapidly in sides chilled at the higher temperature (P < 0.05). Lean color was brightest for carcasses chilled at the higher temperature (P < 0.05), but there were essentially no differences in texture or marbling scores. Steaks from sides chilled at the higher temperatures sheared significantly lower (P <.01), had higher tenderness scores (P <.01), higher flavor scores (P <.01) and had a preferred overall rating by the taste panel (P <.05). There were no significant differences for juiciness scores or for physical measurements of expressible juice. Chemical analyses of samples from both right and left sides were almost identical.