Effects of filleting method, stress, storage and season on the quality of farmed Atlantic cod (Gadus morhuaL.)

Abstract

The effects of filleting method, pre-slaughter stress, storage and season on drip loss, water content, water-holding capacity, rigour contraction and colour in Atlantic cod, Gadus morhua L., were examined. A total of 182 fish were sampled under commercial conditions. To test the effects of filleting method and stress, stressed (S) and unstressed (C) fish were filleted either pre (Pr) or post rigour (Po) at 1 and 48 h post mortem, receptively. The muscle pH significantly decreased from 0 to 144 h of storage in all groups. The onset of the rigour contraction was more pronounced in the Pr-S group as compared with the Pr-C group, but after 144 h of storage, no difference in degree of contraction was observed. Filleting method, stress and storage time influenced the colour of the fillets. Post-rigour filleting caused a significantly increased in measured Lightness (L*) during storage. Stress caused a significant increase in measured redness (a*). No significant difference was found for water-holding capacity. The water content was influenced by filleting method, where the Pr-S group had a significantly lower water content compared with the Pr-C groups; water content changed also according to season. The findings of this study show that stress, filleting method, time of storage and season had a significant effect on the drip loss, where a combination of all factors will determine the total loss.

Effect of Blood Removal Protocol and Superchilling on Quality Parameters of Prerigor Filleted Farmed Atlantic Cod (Gadus morhua)

“…This impression followed throughout the experiments where color measurements 7 d later show no significant difference ( P > 0.07) between processing or chilling method in any of the measured parameters having an average of L* = 83.03 ± 1.55, a* = –3.01 ± 0.91, b* = 14.52 ± 0.89, C* 15.01 ± 0.81, and W = 77.41 ± 1.14. Current results on a* are far less than what has been reported on cod operating with a* values in the range of −1.8 (Digre and others ) and 2.7 to 5.4 (Jørpeland and others ). Furthermore, Digre and others () found a significantly higher redness in fillets that were direct gutted as compared to traditionally gill cutting.…”

“…In correspondence with others on salmon (Bahuaud and others ), superchilling of Atlantic cod resulted in less fillet shrinkage ( P < 0.005) than traditionally iced fillets (Table ). For whitefish, such as Atlantic cod, the degree of shrinkage can vary from 5.4% to 15.5% depending on the seawater temperature and stress (Jørpeland and others ). This is within reason as lower temperature will postpone the onset of rigor mortis.…”

“…Consequently, the postrigor fillet will be less exposed to shrinkage in longitudinal direction than fish being filleted prerigor, but may instead lead to increased amount of fillet gaping. When fish are filleted prerigor, the muscle is free to contract and therefore undergoes shortening and the thickness of the fillet increases (Stien and others ; Jørpeland and others ). Premortem stress and temperature is know to affect postmortem processes such as drip loss (DL), muscle contraction speed and degree of muscle shortening (Stien and others ; Jørpeland and others ).…”

“…When fish are filleted prerigor, the muscle is free to contract and therefore undergoes shortening and the thickness of the fillet increases (Stien and others ; Jørpeland and others ). Premortem stress and temperature is know to affect postmortem processes such as drip loss (DL), muscle contraction speed and degree of muscle shortening (Stien and others ; Jørpeland and others ). How superchilled prerigor fillets from Atlantic cod will act during rigor is still not investigated.…”

Effect of Season, Location, Filleting Regime and Storage on Water Holding Properties of Farmed Atlantic Salmon (Salmo salar L.)

“…This expose the muscle and physically decrease the muscles water holding properties and the water content. Jørpeland, Imsland, Stien, Bleie and Roth (21) found the same effect on farmed cod, where whole fish had 0.5 % more water than hand filleted cod. Filleting by machine as done in the present study might give the muscle increased pressure compared to hand filleting.…”