Impacts of aging/freezing sequence on microstructure, protein degradation and physico-chemical properties of beef muscles.

The objective of this study was to determine the effect of aging/freezing sequence on meat quality, oxidative stability and biochemical attributes of beef muscles. At 3 days postmortem, Longissimus lumborum and Semitendinosus muscles were obtained from 10 beef carcasses, cut into 3 sections and vacuum-packaged. The sections were randomly assigned to aging/freezing treatments (aging only, aging then freezing/thawing, and freezing then thaw/aging). Freezing first then-thaw/aging showed more enlarged gaps between muscle fibers and widely opened extracellular drip channels, resulting in more purge/exudate loss compared to other treatments (P < .05). No differences in other meat quality attributes (e.g. shear force, color and lipid oxidative stability) were found between the aging/freezing sequence treatments (P > .05). A greater desmin degradation was observed in both freezing treatments, while troponin-T degradation was not affected (P > .05). The results suggest that freezing (and aging) itself would be the critical factor affecting those quality attributes of frozen/thawed meat rather than the sequence of aging/freezing.