Project Year 2018
Superb cod from hotel
Cod from the “Cod Hotel” is a top-quality product, if it is handled properly and not kept too long without feed.
This has been stated by scientist Tatiana N. Ageeva in a PhD on live-storage of cod, as part of the research project Catch.
“Live-storage makes it possible to maintain and even improve the quality the fish had at the time of capture,” says Ageeva.
The Nofima scientist has studied the quality changes in wild-caught mature Atlantic cod or skrei, from it is transferred to sea cages until the marketing. The sea cages for livestorage of cod are also called the Cod Hotel.
“According to Norwegian regulations, wild cod can be stored alive for up to 12 weeks, with an initial four weeks without feeding. We have studied how storage in the cod hotel affects the quality of skrei,” explains Tatiana N. Ageeva.
Spawn in the sea cage
Cod that are stored alive in a sea cage must be fed after four weeks. However, it is difficult to get wild cod to accept formulated feed. If the fish are still fasting after eight weeks, the quality will strongly reduce.
“After eight weeks without feeding, the cod had a lower protein content and a higher water content. Fillets got an atypical white colour and gelatinous texture”, explains Ageeva.
The results showed that the cod should be fed during live-storage in cod hotel. This is important with regard to both the quality and welfare of fish. Scientists have been working to develop a suitable feed, with promising results so far.
The study also shows that mature cod spawn in the sea cages – despite the captivity and absence of feed.
“This leads to a considerable reduction in the fish’s weight already at the start of live-storage. The study also found that the absence of feed affects the quality of female cod to a greater degree than males,” the scientist explains.
An extremely relevant issue to ensure the best quality of live-stored cod is the time of filleting after slaughter.
Like everything else that dies, fish also undergo a period of stiffness after death, i.e. rigor mortis. Once rigor sets in, the muscles contract and pull against each other, making the fish stiffen and harden. Such fish is difficult to process without any quality reduction of the final product.
“Fillets made pre-rigor are products of the best quality and have a long marketing time, while fillets processed post-rigor have softer texture and are more prone to fillet gaping during production and thus lose a lot of muscle fluid,” explains Tatiana N. Ageeva.
The study she has participated in shows that the pre-rigor time is reduced when the fish have not been fed for a longer time.
The study also covers how the absence of feed affects contraction and drip loss in different fillet products. The results showed that tails were more prone to contraction and drip loss than loins and whole fillets.
• The goal of the five-year research project Catch has been to maximize the sustainable value of wild Atlantic cod through capture and live storage.
• Catch has resulted in new knowledge about how to achieve better quality and a longer shelf life, as well as development of considerable new expertise at Nofima and our research partners.
• The project has looked at the entire value chain from catch to consumer and has investigated both fresh and frozen filet products, as well as dried and salted products.
• Some of the results show how processing and packaging of cod products can be optimized to provide the best quality and shelf life — and how unique purchasing and consuming experiences may increase the amounts of consumers, which are willing to pay.
• The knowledge gained can be of great value for other parts of the seafood industry where high quality and exclusivity are the keys.
• Three scientists have taken their PhD in this project: Morten Heide, Sarah Joy Lyons and Tatiana N. Ageeva.
IN COOPERATION WITH:
Six research partners and eight industrial partners
The Research Council of Norway