Freezing of pre-rigor fillets of Atlantic salmon

Summary

Atlantic salmon, Salmo salar, were filleted either pre- or post-rigor, and compared after storage as fresh or frozen fillets to investigate how time of filleting and freezing/thawing affected drip loss, texture, gaping, colour and rigor contraction. Unfrozen pre-rigor fillets, contracted about 14% in length during rigor, whereas frozen pre-rigor fillets did not develop appreciable thaw rigor muscle contraction. Absence of rigor contraction seems to affect the quality of frozen pre-rigor fillet quality. After freezing, the pre-rigor fillets had a lower pH than unfrozen fillets. Drip loss during cold storage increased due to freezing, but was not significantly affected by pre- or post-rigor filleting. Freezing reduced initial colour score and firmness, whereas the fillet gaping increased. The effect of freezing was less than the effect of filleting either pre- or post-rigor on fillet gaping. Unfrozen pre-rigor fillets had the highest colour score, less fillet gaping, the firmest texture and the lowest drip loss compared to frozen pre-rigor fillets, or frozen or unfrozen post-rigor fillets.