Researchers led by a team in Norway have been studying how to extract collagen and oil from fish skin and bones, environmental news service Earth.com reported.

While collagen was generally extracted from the skin and bones of pigs or cattle, gelatine derived from fish skin offered a range of benefits, the 10 May report said.

Funded by the Research Council of Norway, the work was carried out as part of the SUPREME project led by Norwegian marine technology and biomarine research company SINTEF Ocean in collaboration with several research partners, including the Norwegian University of Science and Technology (NTNU) and the Technical University of Denmark (DTU).

As well as potentially utilising more than 1M tonnes/year of fish byproducts, the research could alleviate shortages of raw materials in the food and cosmetic industries, the report said.

In addition, fish-derived collagen would allow consumers who avoided meat-based products to enjoy products containing gelatine, SINTEF Ocean senior research scientist Rasa Slizyte said in a 25 April statement on the company’s website.

“If we optimise our exploitation of whitefish residues, we can produce more than 6,500 tonnes of gelatine from fish skin every year,” Slizyte added.

Although the whitefish sector had the potential to supply large volumes of fish skins, there were challenges as many fishing vessels had limited space on board and not all were equipped to supply fresh, high quality raw materials or to freeze them, which was essential to avoid quality deterioration, the company said.

The SUPREME project involved the use of preservation technologies such as freezing, salting and low pH techniques.

All the methods produced satisfactory results, with high gelatine yields and good compositions of amino acids, the research team said.

In addition to its research on whitefish, the SINTEF team conducted research into extracting collagen from the skin and backbones of salmon, which contain more oil compared to whitefish.

When salmon is filleted and deboned, some residual muscle tissue remains attached to the bone. This mixture was well suited for gelatine extraction and the production of oils and protein hydrolysates, the researchers said.

Using tempered water, a hydrolysis process breaks the collagen protein molecules into smaller, taste-neutral peptides.

As part of an EU-funded project called DAFIA, SINTEF researchers have been working to develop a multi-stage processing technology using gentle heat treatment to break down the skin or backbones and remove the muscle fraction, making it possible to extract as much as 90% of the oil.

The research team found that extracting the oil at an early stage preserved its quality. The hydrolysis process also required less water and enzymes to break up the protein molecules.

The results demonstrated that if the source raw materials were of high quality, it was possible to produce high-quality gelatine, oil and taste-neutral proteins, the SINTEF team said.

In addition, extracting most of the oil early in the process reduced energy consumption.

To retain the quality of marine oils and gelatine, it was also important to stabilise them as rapidly as possible, the researchers said.

As part of a four-year research project called OMEGA, financed by the Norwegian Research Council, researchers from SINTEF worked with NTNU, DTU and Indian scientists on improving the extraction of gelatine and oils from salmon.

“These projects demonstrate that it’s entirely possible to make use of all fish raw materials,” Slizyte said.

Having completed its research into whitefish and salmon, Slizyte said the team would now focus on extracting oils from herring.