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Novel processing of pre-rigor farmed Atlantic cod (Gadus morhua) fillets by combining direct filleting and superchilling
TAFT 2012; Clearwater Beach, Florida, 2012-10-30–2012-11-02
The traditional slaughter and filleting process is in short stunning, bleeding, gutting and filleting followed by shipment with wet ice. Direct gutting and filleting without prior bleeding combined with superchilling is a novel way to process farmed fish. To attain knowledge about how direct gutting and filleting followed by superchilling affects the flesh quality, a full factorial design was set up, giving 4 variants. After 7 days in EPS-boxes stored under chilled conditions (approx. 0.5 °C), the fillets were assessed for drip loss, shrinkage, color and texture. The new filleting protocol was performed by direct heading, gutting and filleting without the pre step of bleeding in chilled sea water. Directly after skinning, the fillets were rinsed with chilled fresh water for 10 minutes to remove blood from the fillet. The superchilling was performed in a Nitrogen freezer. The freezer was pre set at – 60 °C, and the exposure time was four minutes, giving an equilibrium temperature in the fillets of -0.7 ± 0.1 °C. The traditionally iced fillets obtained a core temperature of 0°C after 24 hours which was maintained, while the superchilled fillets stayed subzero throughout the observation period. Bleeding regime had no significant (P>0.07) effect on the color parameters, indicating that direct gutting and filleting did not give more residual blood in the fillets. Superchilling reduced the drip loss (P<0.001) with 57 % compared to traditionally icing and gave a significantly (P<0.001) decreased contraction of the fillets compared to traditionally iced fillets. Both superchilling and the direct filleting (P<0.047) gave a softer texture of the surface of the fillets than traditional processing and cooling. The novel process gave a decreased temperature during storage, and reduced contraction and drip loss. The method did not affect the quantity of residual blood, while it resulted in a slightly softer surface texture.