Properties of salmon flesh from different locations on pre- and post-rigor fillets

Farmed Atlantic salmon ( Salmo salar) raised under commercial conditions were slaughtered after rapid live-chilling and processed as pre- or post-rigor fillet loins. These fillet cuts were evaluated for texture, gaping, colour and chemical composition, to determine if loins, or special regional cuts, can be developed as products with different properties. They were evaluated according to time elapsed after filleting. Pre-rigor fillet cuts had significantly firmer texture measured mechanically as breaking strength, less gaping, and improved colour characteristics when compared to post-rigor fillet cuts. When compared at the same time after slaughter, pre-rigor fillets also showed firmer texture and improved colour, but no clear difference in degree of gaping. Upper and lower loins were not different in chemical composition. Lower loins had less gaping and firmer texture in the pre-rigor fillets, but were not different from upper loins in post-rigor fillets. The lower loins had higher colour scores after storage, but these colour differences were more pronounced in the pre-rigor group. Comparison of anterior vs. caudal loins showed significant differences for colour but not texture, with the exception that texture was firmer in the caudal region before storage. We conclude that for most quality parameters measured, pre-rigor fillets are superior to post-rigor. Loins, especially lower and caudal loins from the pre-rigor fillets, could be selected as high value products. The effects on colour and texture of fillets taken pre-rigor as compared to post-rigor were more pronounced than the effects of duration of storage. Free muscle contraction in pre-rigor loins seems to be the major explanation for these differences in colour and texture.