Sorting technology gets more food products from one fish

Scientists from the Chalmers University of Technology in Sweden have developed a new fish sorting technology designed to take as much food product from the fish during processing, similar to how it’s done in the meat processing industry.

Currently fish processing will see fillets removed and the rest of the fish being used as animal food or even discarded as waste, with only half the fish used for food. The new technique has been developed to split the fish up into five components instead of just the fillets.

“With our new sorting method, the whole fish is treated with the same care as the fillet. The focus is on preserving quality throughout the entire value chain. Instead of putting the various side-streams into a single bin to become by-products, they are handled separately, just like in the meat industry,” said the project’s research leader Ingrid Undeland, Professor of Food Science at the Department of Biology and Biological Engineering at Chalmers.

The method involves filleting the fish and then dipping the remaining parts of the carcass into a special solution to allow for further processing. This solution contains ingredients that extend the shelf life of the product. These parts of the fish — the head, backbone, viscera and belly flap, and tailfin — can be then used in other applications such as fish mince, nuggets, oil and even collagen products.

As the belly flap and intestines are rich in marine omega-3, they can be used for oil production. The tail fin has a lot of skin, bones and connective tissue and is therefore well suited to such things as producing marine collagen. In addition to food, marine collagen is also used in cosmetics and ‘nutraceuticals’.

The research was performed as part of the WaSeaBi project, an initiative that is trying to better utilise the by-products of the seafood industry.

“Our study shows that this type of sorting technology is important, particularly as it means we can avoid highly perishable side-stream cuts being mixed in with the more stable cuts. This new method brings fresh opportunities to produce high-quality food,” said Chalmers researcher Haizhou Wu, first author of the scientific article.

A Swedish fish processing company, Sweden Pelagic, is already using parts of the technique in its production and has seen good results.

“The sorting technology gives us many more opportunities to develop healthy, new and tasty foods and to expand our product range,” said Martin Kuhlin, CEO of Sweden Pelagic.

“This year, we estimate we’ll produce around 200–300 tonnes of mince from one of the new cuts and we aim to increase that figure year on year. The interest is there, in the food industry and public meal production segments like school catering.”

The study was published in Food Chemistry.

Image credit: Chalmers University of Technology | Ingrid Undeland