Reports

Dry-aged fish: First trials to a new product

Published:

17/05/2024

Authors:

Cécile Dargentolle and Dóra Svavarsdóttir

Supported by:

Bára Food Fund - 97473

Contact

Cecile Dargentolle

Project Manager

cecile@matis.is

The purpose of the study was to investigate the possibility of slow-aging "dry-ageing" of different types of fish: lean and fatty. Since the dry-ager was homemade, it was not possible to work with a lower temperature than 4°c. We worked with that temperature and saw how the fish reacted to it. By trying to put both fillets and whole fish in a dry-ager, it was found that it took less time for fillets to reach a similar point of action as whole fish. Shrinkage had to be at least 15% in order to achieve the correct effect: improved texture and taste. These studies also showed that a specially designed and constructed dry-ager would give more accurate answers, as both temperature and humidity can be controlled much better, resulting in a much better final product. pH value, color, water content and shrinkage together with sensory evaluation are promising in the use of slow-aging (dry-ageing) of fish to increase shelf life and more valuable sensory evaluation effects. 
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Those trials were aiming at evaluating the feasibility of dry-aging different types of fish: lean and fatty. As the dry-ager was homemade, the temperature could not be lowered lower than 4°C, allowing the trials to see if the fish would support those temperatures. By trying both fillets and full fish to be dry-aged, the project showed that the time in the dry-age would be shorter for fillet to get to a similar stage than full fish. The weight loss of both should at least be 15% to get a desirable stage: improved texture and taste. Those trials also showed us that commercial dry-ager would present more benefits, as with more stability of both temperature and humidity, the quality of the final product will be better. pH, colour, water content and weight loss as well as sensory showed promising results to use dry-aged fish as a preserving technique to improve both shelf life and sensory characteristics of seafood.  

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Reports

Dry-aged fish: Second trials in a commercial dry-ager

Published:

17/05/2024

Authors:

Cécile Dargentolle and Dóra Svavarsdóttir

Supported by:

Bára Food Fund - 97473

Contact

Cecile Dargentolle

Project Manager

cecile@matis.is

The second part of the research on dry-aging fish focused on increasing the understanding of the parameters that work best (temperature, humidity and time) to achieve the desired characteristics of dry-aged fish. Dry-ageing is a process in which the water content of fish is reduced and the fish deteriorates, until the decomposition of the fish slows down enough to ensure low microbial growth (similar to smoked fish). These studies revealed that it is necessary to work with a lower humidity than 82% and a temperature of 2°c is suitable. The shelf life of fish can be extended by dry-ageing, and a whole fish was kept in the dry-ager for 2 weeks and kept for another 2 weeks without spoiling. Experiments with freezing and storage showed that dry-aged fish is suitable for both. These studies make it possible to make the first statements regarding dry-ageing of fish, as these are the first scientific studies that have been carried out. 
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The second batch of trials from the project dry-aged fish, aimed at understanding which parameters would be best (temperature, humidity, and time) to reach satisfactory dry-aged characteristics to the fish. Dry-ageing is a process where the water content in the fish reduces and the fish loses some weight, to reach a stage where the degradation will be slow enough to ensure low bacterial growth (similar to smoked fish). Those trials showed that humidity should be lower than 82% and that 2°C is working. Shelf life of fish can be extended thanks to dry-aging as whole fish could stay in the dry-ager for at least 2 weeks and then stored for 2 more weeks without having any bad attribute developing. Freezing tests and storage tests allowed to show that dry-aged fish supports both processes. Those trials allowed to set the first statements regarding dry-aging fish, with the first scientific data collected. 

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Reports

Gullhausinn / Increasing value of Icelandic cod heads

Published:

30/04/2024

Authors:

Margrét Geirsdóttir, Cecile Dargentolle, Hildur Inga Sveinsdóttir and Sigurjón Arason

Supported by:

AVS fund

Contact

Margrét Geirsdóttir

Project Manager

mg@matis.is

This report is closed

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Reports

Biochar from land-based aquaculture farming

Published:

26/04/2024

Authors:

Anna Berg Samúelsdóttir - Matís, Birgir Örn Smárason - Matís, Jónas Baldursson - Matís, Jónas Viðarsson - Matís, Sylvía Rakel Guðjónsdóttir - First Water, Stefán Jessen - First Water, Helgi Þór Logason - First Water

Supported by:

Hringrásarsjóður

Contact

Anna Berg Samúelsdóttir

Project Manager

annab@matis.is

Land fire is a rapidly expanding industry in Iceland and it is estimated that in the next five years its production will reach around 100-150 tons. Fish whey is an integral by-product from land farming, and its amount is estimated based on the aforementioned production figures to be around 215-353 th. tons. With such an amount of raw material that can be lost during production, it is important to look for all possible ways to capture it with the best available technology at all times instead of pumping it into the surrounding ecosystem with the associated irreversible environmental effects. In addition, there are great opportunities in turning this "waste" into a valuable and sustainable fertilizer or soil amendment, in the spirit of a circular economy, which could revolutionize Icelandic aquaculture as well as agriculture. Especially when you bear in mind that Iceland imports about 50 thousand tons of synthetic fertilizers every year.

This report provides an overview of the progress and main results of the research and innovation project "Biochar from land burning". The goal of the project was to strengthen the circular economy by analyzing aquaculture sludge collected from land-based salmon farms, developing methods for collecting and dewatering the sludge, and examining the possibility of producing biochar from it.

The report reviews the current state of land farming in Iceland and the challenges related to the disposal of fish sludge, the report also provides an overview of the state of affairs regarding the production of biochar, as well as the laws and regulations that need to be considered regarding the use of fish sludge and biochar for fertilizer and soil improvement. The report also provides information on the progress of the project "biochar from land farming" and highlights the main results of measurements, experiments and development on the farm. In order for aquaculture manure from land farming to become a safe and cost-effective source of fertilizer and soil conditioner in this country, research on the raw material and production processes must be strengthened . This study is only one of two that have been conducted in Iceland on the potential of fish farm sludge for fertilizer and biochar production in Iceland. It clearly indicates that our understanding and knowledge of the scope is still in its infancy. But one of the things that stands in the way of research like this is access to funds that support research like this.   

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Land-based salmon aquaculture is a new and fast growing industry in Iceland, with projections suggesting its production will reach 100-150 thousand tons/year in the next five years. An integral side-stream of land-based aquaculture is so-called fish sludge, which consists mostly of faeces and uneaten feed. The volume of such fish sludge coming from a 100-150-thousand-ton salmon production is expected to be 215-323 thousand tons. Given the significant volume of this raw material, it is crucial to employ the best available technology to capture it rather than allowing it to enter the surrounding ecosystem, and thereby avoiding associated irreversible environmental impacts. The opportunities in then turning this "waste" into valuable and sustainable fertilizer or soil enhancer, in the spirit of circular economy, is and option that could revolutionize Icelandic aquaculture and agriculture alike. Especially when considering that Iceland imports approximately 50 thousand tonnes of synthetic fertilizer every year.

This report provides an overview of the progress and main results of the research & innovation project "Biochar from land-based aquaculture farming". The aim of the project was to promote the circular economy by analyzing fish sludge collected from land-based salmon aquaculture farms in Iceland, develop means of collecting and dewatering the sludge, and examine the possibility of producing biochar from the sludge.

The report reviews the current status of land-based aquaculture in Iceland and the challenges associated with disposal of fish sludge, it also provides an overview on the state-of-art regarding biochar production, and regulatory constraints for the use of fish sludge and biochar . The report then provides information on the progress within the project and highlights the main results.

For fish sludge from land-based aquaculture to be viable as a potential fertilizer in the future, research on the raw material needs to be intensified. This study represents only one of two conducted in Iceland, indicating that our understanding and definition of fish sludge applications for biochar or as a fertilizer are still in their infancy. 

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Reports

CRISP-FISH: Rapid Species Identification in Fish

Published:

19/04/2024

Authors:

Sæmundur Sveinsson, Guðbjörg Ólafsdóttir and Björn Þór Aðalsteinsson

Supported by:

Icelandic Food Innovation Fund (is. Matvælasjóður)

Contact

Sæmundur Sveinsson

Research Group Leader

saemundurs@matis.is

This report is closed. / This report is closed.

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Reports

Distribution of arsenic species by seaweed parts, especially arsenic lipids

Published:

02/04/2024

Authors:

Rebecca Sim, Ásta H. Pétursdóttir, Natasa Desnica, Jörg Feldmann, Guðmundur Haraldsson, Karl Gunnarsson, Liberty O'Brien, Marta Weyer and Hildur I. Sveinsdóttir.

Supported by:

Icelandic Research Fund

Contact

Rebecca Sim

Ph.D. Student

rebecca@matis.is

Distribution of arsenic species within the macroalgae 
– an emphasis on arsenolipids

Algae are rich in minerals and desirable bioactive substances, but they can also absorb large amounts of trace elements, such as toxic heavy metals, including the element arsenic. Arsenic is found as inorganic arsenic in the sea and is taken up in that chemical form by the algae. In the algae, however, arsenic is detected not only as inorganic arsenic but as a wide range of arsenic compounds, so-called organic compounds of arsenic, for example arsenosaccharides and arsenolipids. There is still a lot of mystery about the origin of these compounds. In general, organic forms of arsenic have been considered quite harmless, unlike inorganic arsenic, which is a known carcinogen. However, recent studies on arsenolipids have shown that they can be as cytotoxic as inorganic arsenic. It is also believed that arsenosugar can possibly have long-term negative effects with regular consumption. Levels of arsenolipids are generally not high in algae, but the starting point of their production is thought to occur in algae. Algae are part of the regular food intake in the Eastern part of the world and are becoming increasingly popular in the West, so more information about these compounds is urgently needed to fully assess the risks associated with their consumption as well as to ensure that appropriate regulations are put in place regarding their maximum levels in foodstuffs. In order to understand the toxicological effects of algae consumption, it is extremely important that more data be collected on all the different chemical forms of arsenic, in particular on arsenolipids, but limited information is currently available on them. Samples of red, green and brown algae were collected near Grindavík and Kjalarnes, at two different points in time. The samples were thoroughly analyzed for heavy metals and arsenic analysis was carried out to better understand the chemical form in which the arsenic was present. Selected samples of brown, red and green algae were measured for species analysis of arsenolipids using mass spectrometry HPLC-ICP-M/ESI-MS/MS and HPLC-qToF-MS. In addition, brown macroalgae were divided into biological fractions to determine whether the distribution of arsenic species is uniform throughout the seaweed. Limited information exists globally on arsenolipids in seaweed, so this extensive profiling of them in different species of algae will help elucidate how these enigmatic organic compounds are formed and where they are stored. The data can also be used for risk assessment of arsenic species in seaweed for human consumption and can therefore influence future food safety legislation.
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In recent years seaweed has gained popularity as a health food due to its high content of minerals and vitamins. However, seaweeds may also accumulate high levels of potentially toxic elements – in particular arsenic, which may become incorporated into larger biological molecules such as sugars and lipids. It is unclear how these organic arsenic compounds are formed/stored and if they may serve a biological purpose (ie, detoxification or energy storage). However, toxicological studies into arsenic-containing lipids have demonstrated cytotoxicity comparable to that of arsenite, a known carcinogen, and arsenic-containing sugars are suspected to display toxicity with chronic exposure. This project aims to investigate variations in the distribution of arsenic compounds throughout several classes and species of seaweed. Samples of brown, red and green macroalgae were collected from two locations in Iceland across two different months and analyzed for several potentially toxic elements as well as hydrophilic arsenic speciation using HPLC-ICP-MS. Brown macroalgae were additionally sectioned into anatomical parts to determine if the distribution of arsenic species differs throughout the thallus. Select samples were chosen for state-of-the-art lipophilic arsenic speciation using HPLC-ICP-MS/ESI-MS/MS and HPLC-qToF-MS. Limited information is available on arsenic speciation in seaweed thus it is hoped that this extensive profiling of several different species will help elucidate how these unusual compounds are formed and stored. The data from this project will also contribute to the necessary information needed for the risk assessment of arsenic species in seaweed for human consumption and may have an impact on future food safety legislation.

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Reports

Rapid methods for quality evaluation: Evaluation of salted cod following desalting, freezing and storage

Published:

21/03/2024

Authors:

Hildur Inga Sveinsdóttir, María Guðjónsdóttir, Sigurjón Arason, Cecile Dargentolle and Kolbrún Sveinsdóttir

Supported by:

AVS Research Fund and Food Fund

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

This report is closed. 

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Reports

Impact of water origin and composition on the desalination of fully salt-cured cod

Published:

21/03/2024

Authors:

Cecile Dargentolle, Maxime Dupont, Hildur Inga Sveinsdóttir, Sigurjón Arason and Kolbrún Sveinsdóttir

Supported by:

AVS Research Fund and Food Fund

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

This report is closed. 

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Reports

The effect of different desalting methods on the quality of injected brine and pickle salted frozen cod (Gadus morhua)

Published:

21/03/2024

Authors:

Cecile Dargentolle, Hildur Inga Sveinsdóttir, Sigurjón Arason and Kolbrún Sveinsdóttir

Supported by:

AVS Research Fund and Food Fund

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

This report is closed. 

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Reports

Shelf life of differently treated thawed desalted cod loins and tails after storage at -25°C up to 27 months

Published:

21/03/2024

Authors:

Cecile Dargentolle, Hildur Inga Sveinsdóttir, Jónas Baldursson, Sigurjón Arason and Kolbrún Sveinsdóttir

Supported by:

AVS Research Fund and Food Fund

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

This report is closed. 

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