Nofima scientists have unveiled a new protein-based process additive with triple benefits that can contribute to reducing the loss of feed in the aquaculture industry and make the production of feed more energy-efficient.
The additive, which can be made from marine raw materials or plant proteins and is said to have triple benefits, functions as a binding agent, has high nutritional value and is said to make it easier to produce fish feed with good physical properties.
Around 1.5 million tonnes of feed are used for Norwegian-farmed salmon each year, according to Nofima scientists. The feed is blown through long tubes into the fish cages, and so it’s important that the feed is manufactured to withstand the mechanical load it experiences to prevent it breaking up and clogging the feed-supply system.
Currently, the loss in such feed delivery systems is around 0.3-1.5%, which corresponds to an additional annual cost of between NOK 40 and 200 million. In order to reduce the loss, the feed must be homogeneous and have good physical properties.
According to Nofima research, the physical properties of the fish feed can be controlled and improved by adding starch and other binding agents.
An increasing amount of the proteins in commercial fish feed comes from the plant kingdom, and the fraction of proteins from marine raw materials is decreasing. Nofima says this raises new challenges, and more knowledge about the technical properties of the ingredients used in fish feed manufacturing is needed.
Positive properties are associated with water-soluble low-molecular-weight proteins in the fishmeal (small peptides and amino acids) which are pressed out together with water during the manufacture of fishmeal. The water that is pressed out is called stickwater, and has a positive nutritional value, says Nofima.
“We have shown how such proteins function during the manufacture of fish feed, and we have identified which type of proteins gives the desired effect. This means that we can use them better, not only to make the processing from raw material to pellet easier, but also as binding agent and nutritional component,” said PhD student Tor Andreas Samuelsen at the Nofima Feed Technology Centre.
Nofima says the knowledge may also contribute to reducing the need for reprocessing of feed and give fewer complaints arising from poor physical properties of feed.
