Quality clipfish and producers will be properly paid. The new water measuring instrument that Jens Petter Wold and his colleagues have invented will ensure that everyone gets more out of clipfish.

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  Georg Mathisen

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The project partners in Sunnmøre would have liked to have had the new instrument yesterday. “We have been to Ålesund twice and demonstrated different prototypes,” says Wold.

He is a senior scientist at Nofima, and together with his colleagues and scientists at SINTEF Digital, he has created a completely new instrument to find out how much water clipfish contains.

Quality and price

But why is it necessary to measure the water content of fish that have already been dried? “This is an important quality characteristic,” explains Jens Petter Wold. Put differently, the amount of water it contains determines its taste, consistency and shelf life. Moreover, the water content determines how much Norwegian producers are paid.

“Generally speaking, the lower the water content, the longer the fish will last. Lower water content also results in a different structure and quality,” says Wold. In addition, the less water it contains, the more expensive the fish will be.

Stricter control

Norwegian clipfish is exported all around the world, but different countries have different rules. Jens Petter Wold talks about how the gigantic bacalhau country Brazil has implemented stricter control.

“If you send fish to Brazil and it turns out that it contains more than 53 percent water, you may have to pay a lot more in fees. In the worst case, the container will be sent back full of clipfish. It is a similar situation in Portugal, but with a different water content limit,” he says.

This means that knowing exactly how much water the clipfish contains is really important. The water content must not exceed the limit set by customers, but it shouldn’t be too far below the limit, either. Not enough water means fewer kilograms, and that is bad business for the producer. Therefore, it is important to measure the water content of as many fish as possible, and not just take spot checks.

Measured by eye

“The traditional measurement method involves trained sorters conducting a manual assessment, but it is a craft that one has to learn. It is not that easy to get hold of people who are interested in learning these kind of things today,” says Wold.

The official standard method of water measurement is to cut the fish into pieces, weigh it, dry it overnight and then weigh it again. One can then calculate how much water it contained. However, this is time-consuming and you also ruin quite a lot of fish.

“This means that the industry is in need of a measuring instrument. It should be handheld and flexible so that it can be used at different points in the process.”

Almost visible light

The solution is based on near-infrared spectroscopy (NIR). Near-infrared light has a longer wavelength than visible light and is therefore just past what is visible to the human eye. On a rainbow, these rays of light are located just outside the colour red.

“Near-infrared light is projected into the food. These are rays of light that penetrate quite deep into fish, for example,” he explains. Some of the rays are absorbed by water, others are absorbed by protein. Based on the signals measured, it is possible to determine the water content in seconds.

The instrument developed by Jens Petter Wold and his colleagues ensures that measurements can be taken deep into the fish, which is important for obtaining good measurements of water content.

This is not the first time the clipfish industry has tested a solution based on NIR. 15-20 years ago, Jens Petter Wold worked on developing an industrial scanner. At that time, the technology was relatively young and the industry did not face such strong demands from customers around the world. The knowledge gained from back then is nevertheless the starting point for today’s research.

Impatient industry

“We have now come so far that we know how this can be used in practice and put into a small instrument. An instrument like this can quickly measure the water content without touching the fish, and  the industry is therefore impatient and looks forward to testing the new technology,” concludes Jens Petter Wold.

Facts about the research

The research has been carried out in the project Calibrated handheld NIR prototype for water determination in clipfish, and is funded by FHF – Norwegian Seafood Research Fund.

This project started in 2021 and will conclude at the end of 2023. It is led by Nofima, represented by Jens Petter Wold. Other project partners include ANFACO (Asociación Nacional de Fabricantes de Conservas de Pescados), Sintef Digital, Brødrene Sperre, Andreas Bjørge.

A new project called Senselnside will be the next step in the research that focuses on the further development of the instrument and mapping of market opportunities. Project partners are Sintef Digital and Nofima.

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