Quality changes in cod (Gadus morhua) and redfish (Sebastes marinus) loins and tails during frozen storage

• Published in: Journal of food composition and analysis 2024-06, Vol.130, p.106188, Article 106188
• Main Authors: Nguyen, Hang Thi, Sveinsdóttir, Hildur Inga, Arason, Sigurjón, Gudjónsdóttir, María
• Format: Article
• Language: English
• Subjects: Cod; Lipid changes; Protein denaturation; Protein oxidation; Redfish; Water holding capacity
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2024.106188

The muscle structure and composition may vary along the different portions of fish fillets, which can complicate the quality and storage stability of products. Loins and tails from Atlantic cod (Gadus morhua) and redfish (Sebastes marinus) fillets were therefore stored at −25 °C up to 16 months and 20 months, respectively, to investigate the quality changes influenced by the duration of frozen storage within the fillet portions. Throughout the storage period, the loss of total sulfhydryl groups correlated with increased disulfide bonds, indicating partial oxidative protein degradation. This may be linked with protein denaturation as evidenced by the decrease of soluble proteins, as well as decreased water holding capacity and increased thawing drip loss and cooking loss. The results from the cod samples reveal that stronger degradation changes occurred in the tail. The loin, therefore, had more storage stability as well as higher nutritional value. However, other quality attributes were similar between the two portions in the redfish fillets. Higher free fatty acid (FFA) values, lower soluble protein contents, and higher disulfide bond contents were obtained in the cod samples compared to the redfish samples at the same storage time, indicating that lipid hydrolysis and protein degradation effects were stronger in the cod (lean fish) compared to redfish (medium fat species). •Partial protein degradation occurs during the frozen storage of cod and redfish.•Protein degradation is associated with loss of water retention properties.•Cod loins have higher nutritional value and slower degradation than the tail.•Quality attributes and stability are similar between the loins and tails of the redfish.•Cod shows stronger protein degradation during frozen storage compared to redfish.