Reports

Gæðakræklingur er gulls ígildi / Icelandic blue mussels - A valuable high quality product

Published:

01/12/2011

Authors:

Natasa Desnica, Sophie Jensen, Guðrún G. Þórarinsdóttir, Jón Óskar Jónsson, Hörður G. Kristinsson, Helga Gunnlaugsdóttir

Supported by:

AVS

contact

Natasa Desnica

Group Leader

natasa@matis.is

Gæðakræklingur er gulls ígildi / Icelandic blue mussels - A valuable high quality product

In order for Icelandic mussel farming to grow and prosper, it is important to carry out basic research into the safety and quality of fresh Icelandic mussels that can be used by producers in marketing and selling the products. The purpose of this eighteen-month research project was to collect information on the safety and quality of mussels (Mytilus edulis) in market size (> 45 mm) grown off the coast of Iceland. A total of thirteen market-sized mussel samples were collected at four different breeding sites inland (Hvalfjörður, Breiðafjörður, Álftafjörður and Eyjafjörður) at different times of the year. Market-sized mussels were not found in Eskifjörður and this breeding site was therefore excluded from the project. Instead, samples were taken more often at the other four breeding sites than originally planned. Mussels were collected from breeding lines and time and location recorded. Weight, height and body mass were measured. The mussel was sexed and the stage of puberty was estimated in each sample. In this project, significant information was collected on nutrient content (protein, water, fat, ash) as well as bioactive substances such as selenium, zinc, carotenoids and fatty acid compositions in mussels from different cultivation sites and at different seasons. Unwanted inorganic trace elements (lead, mercury, cadmium, copper, nickel, arsenic, chromium and silver) were also measured in all samples. Work was also done on setting up and testing rapid measurement methods for measuring three types of algae toxins, ie ASP, PSP and DSP. The measurement methods were optimized against the equipment available at Matís and also measured reference samples (ie mussels with a known amount of algae toxin) to assess the quality of the measurements. Two types of rapid tests available on the market were tested to assess their performance in algae toxicity measurements in mussels. On the one hand, so-called Jellet tests were tested and on the other hand ELISA tests. The result is that both tests are relatively simple to use, however, it is necessary to test them on slightly more samples than was done here, in order to make a better assessment of how best to use them in quality control of mussel farming. It is necessary to be aware of the limitations of these rapid tests as they will not completely replace measurements by approved research methods. These tests, on the other hand, could significantly reduce the number of samples sent for approved measurements, as no samples would be sent when the pre-tests show that algae toxins are present and no mussels were allowed to be harvested. The results indicate that Icelandic mussels have an optimal nutrient composition, which is subject to natural seasonal changes. Multivariate analysis (PCA) shows that mussels contain a higher percentage of fat and protein in the spring (May and June), probably because the mussel is preparing to spawn at this time of year. In early autumn, the protein content decreases while the amount of unknown substances increases. At this time of year, spawning is complete, if not complete. The analysis also shows a weak positive correlation between protein and fat, but a strong negative correlation between protein and unknown substances. The concentration of heavy metals (mercury, lead, cadmium) was generally low, but in some cases the concentration of cadmium was higher than permitted by Icelandic and European Union regulations (1 mg / kg). It is therefore important to monitor the concentration of cadmium in Icelandic mussels before they go on the market. The results of fatty acid analysis show that Icelandic mussels contain significant amounts of the omega-3 fatty acids EPA (C20: 5n3) and DHA (C22: 6n3) as well as Palmitoleate (C16: 1n7), all of which are known for their beneficial effects on health. The results of the project show that Icelandic mussels are competitive in terms of nutrient composition and also contain positive bioactive substances. These results will undoubtedly be useful to mussel farmers in marketing presentations and planning regarding the harvesting and sale of mussel products.

In order to enable the Icelandic blue mussel industry to grow, market and sell their product, there is a critical need to perform some fundamental studies. The purpose of this eighteen months long research project was to investigate the quality and value of Icelandic blue mussels (Mytilus edulis) grown at different growing sites of Iceland. A total of 13 samples were collected from blue mussel culture sites around Iceland (Hvalfjörður, Breiðifjörður, Álftafjörður and Eyjafjörður). The Eskifjördur sampling site was excluded from the project due to the lack of market sized blue mussels and resulted in sampling from growing lines of four different culture sites. The mussels were characterized according to location, time of year, weight, length, meat yield and reproductive status. This report summarizes the considerable amounts of data obtained regarding the chemical composition of Icelandic blue mussels, including trace metals (lead, cadmium, copper, zinc, mercury, arsenic, selenium, chrome, nickel and silver), nutrients (moisture, protein, lipid and ash content) and bioactive components (carotenoids and fatty acid profile). In addition, the presence of common algal toxins in blue mussels was investigated and concluded that further work will be needed to optimize the rapid assays tested for measuring algal toxins ie PSP and DSP toxins. The results obtained need to be further verified by using standard addition procedures or with certified reference material. It is important to keep in mind that these rapid tests for PSP and DSP only provide screening results. Further testing with reference analytical methods will be required to confirm the results from these rapid tests before the mussels are harvested and sold on market. The rapid tests are suitable for quality control and decision making regarding whether or not it is safe to harvest the mussel crop or if the mussels should be harvested later after purification in the ocean. The results obtained here indicate that Icelandic blue mussels compose well balanced nutritional and trace element levels. A moderate seasonal variation pattern was observed in all measured nutritional parameters. A principal component analysis (PCA) showed that mussels contained higher proportion of fat and protein during spring (May ‐ June). In the autumn the proportion of protein reduced while the proportion of other unknown substances increased. The PCA analysis also revealed a weak positive correlation between protein and fat and a strong negative correlation between protein and other unknown substances. Heavy metal concentrations were generally low. However, elevated levels of cadmium were measured in mussel samples from certain culture sites, which in some cases exceeded the maximum EU limits (1 mg / kg) for cadmium in bivalve molluscs. The fatty acid profile revealed significant levels of omega ‐ 3 polyunsaturated fatty acids such as Eicosapentaenoic (EPA, C20: 5n3) and Docosahexaenoic (DHA, C22: 6n3) as well as Palmitoleate (C16: 1n7), all recognized for their health beneficial effects . This fundamental information proves that Icelandic blue mussels is a market competitive product of high quality and will greatly aid in developing the Icelandic mussel industry and in making the best choices considering growing, harvesting, marketing and selling their products.

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Reports

Gold in the fists of Ægis / Antioxidants from Icelandic marine sources

Published:

01/05/2010

Authors:

Rósa Jónsdóttir, Patricia Hamaguchi, Guðrún Ólafsdóttir, Tao Wang

Supported by:

AVS R&D Fund of Ministry of Fisheries in Iceland

contact

Rósa Jónsdóttir

Group Leader

rosa.jonsdottir@matis.is

Gold in the fists of Ægis / Antioxidants from Icelandic marine sources

The purpose of this project was to screen for anti-corrosive substances from Icelandic seafood such as algae, capelin and sagebrush, to be used as a food additive, target food or as a dietary supplement. Particular attention was paid to the possible use of polyphenols from algae as natural antioxidants to prevent the development of fish products and fish muscle proteins (isolates). This was done by screening for antioxidant activity with several types of antioxidant tests. The most promising antioxidant was chosen to better study its antioxidant properties in food models, i.e. washed cod muscle system, cod protein system and in fish burgers. The results showed, among other things, that polyphenols from the seaweed (Fucus vesiculosus) have high antioxidant properties and are promising for use as a dietary supplement or in food to promote greater stability, taste and nutritional value.

The aim of this project was to explore the natural antioxidant activity of marine sources like seaweed, capelin and cod spleen to use as food additives, functional ingredients or nutritional supplements. The potential application of algal polyphenols as novel natural antioxidants to prevent lipid oxidation of fish muscle and fish protein based products was of special interest. This was done by screening for antioxidant activity using different types of antioxidant assays. The most promising antioxidants were selected and their antioxidant properties studied further in fish model systems and fish patties. The results showed that phlorotannins isolated from bladderwrack (Fucus vesiculosus) had very high antioxidant properties and has a potential as nutritional supplements or food additive to enhance oxidative stability, flavor quality and nutritional value.

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Reports

Bioactive products in the production of halibut and cod larvae / Bioactive products in production of halibut and cod larvae

Published:

01/12/2008

Authors:

Jónína Þ. Jóhannsdóttir, Rannveig Björnsdóttir, Eydís Elva Þórarinsdóttir, Kristjana Hákonardóttir, Laufey Hrólfsdóttir

Supported by:

AVS, Matvælasetur HA

Bioactive products in the production of halibut and cod larvae / Bioactive products in production of halibut and cod larvae

The aim of the project was to find ways to improve the survival and quality of cod and halibut larvae and to use environmentally friendly methods. The aim was also to open up the possibility of utilizing saithe peptides that could increase the value of saithe. The results of a previous project in halibut farming were promising and indicated that it was most convenient to treat larvae with peptides through feed animals, in addition to which it was necessary to further investigate the concentration of treatment. In connection with the project, new facilities for animal husbandry have been developed and set up at Fiskey hf. for research into the different treatments of feed animals and thus contribute to increased stability in the production of halibut juveniles. Repeated experiments with bioactive substances in the cultivation of equidae have been carried out and they seemed to tolerate a certain concentration of the substances. The main results of experiments in the early stages of cod farming indicate that treatment with saithe peptides results in good growth, noticeably faster development of internal organs and a much lower incidence of larval defects. However, it is clear that the effects of different levels of treatment need to be further investigated. There is strong evidence that IgM and lysozyme are present in cod larvae soon after hatching or much earlier than previously claimed, and that treatment appeared to stimulate their production. Treatment with saithe peptides does not appear to affect the bacterial flora of larvae, but a specific species composition was detected in the gastrointestinal tract of larvae in pots where larval survival and quality were optimal. This gives evidence that a certain species composition of bacterial flora is favorable for cod larvae.

The main goal of this project was to increase viability and quality of cod and halibut larvae before and during the first feeding period by using bioactive products. The aim was also to increase the exploitation and value of pollock. The findings of previous projects in halibut culture were promising and indicated that treating live feed is a suitable method to carry bioactive products to the larval intestines during first feeding but the intensities of treatment needed to be further investigated. New facilities have been developed in relation to the project for research in the live feed culture at Fiskey Ltd. to promote increased stability in the production of halibut fingerlings. Repeated experiments have been conducted in the culture of rotifers and results indicate good tolerance towards treatment with bioactive products in certain intensities. The overall results of the project indicated that pollock peptides may promote increased growth and quality of cod larvae during first feeding. The results also indicate the presence of IgM and lysozyme early post hatching, but it has not been observed in cod larvae of this size before. Furthermore, results also indicate that hydrolysates from pollock can stimulate the production of these factors in cod larvae. Treatment using pollock peptides, did not affect the bacterial community structure of live feed or cod larvae, however a similar structure was observed in larvae from the most successful production units different from other tanks. The results therefore indicate a bacterial community structure that may be preferable to the cod larvae.

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Reports

Use of bioactive substances in halibut farming

Published:

01/12/2007

Authors:

Jónína Þ. Jóhannsdóttir, Heiðdís Smáradóttir, Jennifer Coe, Rut Hermannsdóttir (MS student), María Pétursdóttir, Rannveig Björnsdóttir

Supported by:

Líftækninet HA (2005-2007), KEA University Fund (2006)

Use of bioactive substances in halibut farming

The main goal of the project was to promote the increased performance of halibut in fire and use environmentally friendly methods. Bioactive substances were used that were easy to obtain, contributed to the increased value of seafood and also had some of the desired activity, ie. bactericidal / inhibitory, prebiotic or immunostimulatory activity. Experiments were made with various materials in the project, ie. chitosan derivatives as well as peptides derived from blue whiting, cod and saithe. The effect of treatment with the substances was assessed in terms of the growth and performance of larvae and forage animals as well as in terms of the composition of the bacterial flora and the stimulation of a non-specific immune response in larvae. The main results indicate that the most suitable method for introducing substances into larvae is to use feed animals (Artemia) and a method was developed in the project to treat them. The bioactive substances did not appear to have a bactericidal effect in the rearing environment of the feed animals, but did contribute to a change in the composition of the bacterial flora. Bioactive substances seemed to be used primarily as supplements as feed animals were plump and playful. The performance and quality of larvae in the breeding units of Fiskey hf. is very different and there is no obvious relationship between the performance of the peritoneal stage and the performance and quality of the larvae at the end of the initial feeding. The composition of bacterial flora was also found to be very different in peritoneal larvae and larval feeding larvae. Three separate experiments were carried out in the Fiskey juvenile farm where the larvae in the initial feeding were treated with bioactive substances. The main results showed that it is important to treat with the right concentration of substances and for a reasonably long time as too much concentration can have a negative effect on the growth and metamorphosis of larvae. Treatment with blue whiting peptides was thought to give promising results and have a beneficial effect on larval metastasis. Bioactive substances did not appear to have a decisive effect on the number of bacterial bacteria in the gastrointestinal tract of larvae, but treatment with blue whiting and cod peptides could potentially alter the composition of the flora. Studies on the non-specific immune response of halibut larvae revealed the presence of C3 and Lysozyme from the end of the peritoneal stage, but IgM production does not begin until about 28 days after the start of feeding. Higher levels of IgM were detected during the first weeks in larvae treated with saithe peptides and this may indicate an immunostimulatory effect. The results of the project as a whole indicate that the bioactive substances studied did not have a decisive effect on the bacterial flora of the farm, but the treatment of larvae in starter feeding with the right concentration of bioactive substances could have a good effect on larval performance and stimulate larval immune response. of the farm when they have not yet developed a specialized immune response.

The aim of this project was to promote increased survival of halibut larvae during first feeding by using bioactive products. The bioactive products were selected by the criterion that they were easily accessible and induced any of the desired effects ie inhibiting bacterial growth, prebiotic effects or immunostimulants. The products studied are chitosan and peptide hydrolysates from blue whiting, cod and saithe. The effects of treatment were evaluated with respect to growth and survival of larvae and the live feed (Artemia) as well as effects on bacterial numbers or the community structure of the intestinal microbiota of larvae and stimulation of the innate immune system of the larvae. The results indicate that treating live feed (Artemia) is a suitable method to carry the bioactive products to the larval intestines during first feeding and a new technique has been standardized for treatment of the live feed with the products. The bioactive products did not affect the total bacterial count in the Artemia but the composition of the bacterial community may be changed as a result of the treatment. The Artemia seems to use the bioactive products as a food supplement and was well suited to be used as live feed. A significant variation in overall success of larvae was observed without any obvious correlation between survival of larvae at the end of the yolk sac stage and at the end of first feeding. A different bacterial pattern was observed in the intestine at the yolk sac stage compared to first feeding larvae. Three separate experiments were carried out in the halibut production units at Fiskey Ltd. where larvae were treated with various bioactive products. The results emphasize the importance of treating larvae with the appropriate concentrations of the products, as elevated concentrations can negatively affect growth and metamorphosis of the larvae. Treatment with peptides from blue whiting resulted in relatively good survival of larvae with similar success of metamorphosis compared to control units. The bioactive products did not affect bacterial growth but there were indications that peptides from blue whiting and cod may affect the composition of the intestinal community of bacteria in the larvae. Results from studies of the immunological parameters indicate the presence of C3 and Lysozyme already from the end of the yolk sac stage and the initialization of IgM production after approximately 28 days in feeding. Production of IgM was stimulated in larvae treated with peptides from saithe, indicating immunostimulating effects of this product. The overall results indicate that the bioactive products studied did not affect the bacterial flora during the first production stages of halibut larvae. However, if used in the appropriate quantities and at the right time, the products may promote survival and growth and stimulate the innate immunity of larvae.

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Reports

Isolation and processing of bioactive peptides from underutilized species of marine organisms - preparation and formation of networks

Published:

01/05/2007

Authors:

Sigurður Vilhelmsson, Guðmundur Gunnarsson, Guðjón Þorkelsson

Supported by:

AVS Fisheries Research Fund

contact

Guðjón Þorkelsson

Strategy & Stakeholders

gudjon.thorkelsson@matis.is

Isolation and processing of bioactive peptides from underutilized species of marine organisms - preparation and formation of networks

In this preliminary project, preparations were made for the establishment of a center in the Westman Islands that will specialize in research, processing and marketing of products made from by-products of fish processing and underutilized species. The long-term goal is to start processing bioactive substances from seafood. To bridge the gap between raw material sourcing and specialized processing of bioactive substances, the center was expected to embark on projects that increase the value of by-products. A network was formed to ensure the development of skills and knowledge regarding the processing of bioactive and pharmaceutical forms. The network brought together both foreign and domestic researchers and stakeholders. Applications for collaborative projects were sent to Nordforsk and the NORA Fund, as well as applications to the ACP Fund with companies in Iceland for slag digestion processing, value added and product development. These emphases were also successfully incorporated into proposals for the Growth Agreement of the South, which was signed in October 2006. The collaboration will continue and the aim is to establish large international research projects on bioactivity in seafood. Special attention is paid to the 7th EC Framework Program. The group is also working on reviewing the status of each individual's knowledge and skills, and subsequently aims to publish a peer-reviewed review article on bioactive peptides in seafood.

The foundation of an R&D center in Vestmannaeyjar for utilizing marine byproducts by turning them into commercially viable products was prepared. The aim of the center is to establish state of the art of the processing of bioactive compounds from marine by-products and underutilized species. A small Nordic knowledge network to build competence and skills regarding bio processing of bio- and pharmaceutically active compounds was also established. The network now consists of scientists and industry related stakeholders from Norway, Scotland, Finland and Iceland. The network partners have decided to work together on joint international grant applications for R&D projects in marine bioprocessing. The network is currently comparing resources of knowledge and subsequently the aim is to publish a peer reviewed state of the art review of marine bioactive peptides.

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