EFFECTS OF PRERIGOR CHILLING AND FREEZING AND SUBCUTANEOUS FAT COVER UPON THE HISTOLOGICAL AND SHEAR PROPERTIES OF BOVINE LONGISSIMUS DORSI MUSCLE

Abstract

A total of 119 bovine carcasses were utilized in three separate but related experiments to evaluate histological and textural parameters of the longissimus dorsi muscle at 45 min postmortem (unchilled), at 90 min postmortem (45 min cooler chill) and after a 24-h chill in a cooler at 2 °C. Samples were also examined after prerigor (90 min postmortem) freezing at −18 °C and subsequent slow thawing (24 h at 2 °C). The composite results of these experiments provide no evidence that conventional chilling of carcasses, with a subcutaneous fat cover of 4.57–19.56 mm at the eleventh thoracic vertebra, produced detrimental effects (P < 0.05) upon certain histological or textural properties of bovine longissimus dorsi muscle. However, prerigor freezing and subsequent thawing produced substantial (P < 0.05) effects on the susceptibility of fibers to fragmentation and incidence of wavy fibers, but did not produce detrimental effects (P > 0.05) on tenderness under the conditions imposed in the present study. The results from the present study also demonstrated that the issues involved in the transition of muscle to meat are far from resolved, and that additional research will be required to document fully the relevance of carcass chilling and meat handling procedures to meat quality. Key words: Beef, histological properties, shear values, prerigor chilling, prerigor freezing, fat cover