THE EFFECTS OF DELAYED CHILLING AND ALTERED CARCASS SUSPENSION UPON BEEF MUSCLE: I. PHYSICAL AND TEXTURAL PROPERTIES

A total of 60 bovine carcasses from crossbred heifers, 12 to 16 months of age with carcass weights of approximately 260 kg were utilized in two related experiments to evaluate the effects of delayed chilling and altered carcass suspension on certain physical and textural properties of beef muscle. Hip-free suspension (suspension by the os coxae from a hook inserted through the obturator foramen with the limbs hanging free) significantly (P<0.05) reduced the shear force values obtained on samples from the longissimus dorsi (LD) and semimembranosus (SM) muscles but had no effect (P>0.05) on shear force values obtained on samples from the psoas major (PM) muscle. The only other physical property affected by altered carcass suspension was objective measurement of lean color in the SM. Carcasses suspended from the aitchbone had darker SM muscles. Delayed chilling treatments had no effect (P>0.05) on 2-h SM pH values or 144-h pH values for any of the muscles studied. However, carcasses held at either 13°C or 22°C for 24 h had higher (P<0.05) SM pH values. When delayed chilling treatments affected muscle color, treated sides had darker lean than their conventinally chilled counterparts. Textural properties (shear values and taste panel tenderness ratings) and amount of expressible juice generally were unaffected by the delayed chilling treatments evaluated.