Abstract
The effects of freezing rates and subsequent storage temperatures on the functional properties of meat were assessed. In the first
trial, 24 Semitendinosus muscles were allocated to four freezing treatments to determine the effect of freezing rate alone (no frozen
storage) on the functional properties of thawed muscle proteins. In the second trial, the effect of freezing rate, storage temperature
and time were determined: 24 semimembranosus muscles were assigned to 30 treatment combinations using an incomplete factorial
design with two freezing rates three storage temperatures five storage times. All samples individually sealed in water
impermeable bags were thawed in water at 10 C and then analysed. The rate of freezing alone in both trials and for both muscles
had no effect on protein solubility; sulphydryl content; surface hydrophobicity; emulsion activity index or meat colour. Slowly
frozen semimembranosus had more drip than fast frozen muscles. Semimembranosus muscle sarcoplasmic protein solubility
increased and myofibrillar protein solubility decreased with storage temperature below 18 C. Storage temperature did not affect
the other attributes measured. Functional properties were mainly affected by storage time and the interaction between storage time
and freezing rate. It is concluded that the current practice of blast freezing and storage at 18 to 20 C is sufficient to maintain the
quality of manufacturing beef.
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