Reports

Impact of season, bleeding methods and storage temperature on the quality and stability of frozen cod climbs

Published:

01/04/2016

Authors:

Magnea G. Karlsdóttir, Sigurjón Arason, Ásbjörn Jónsson

Supported by:

AVS Fisheries Research Fund

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Impact of season, bleeding methods and storage temperature on the quality and stability of frozen cod climbs

The main goal of the project was to increase utilization and at the same time knowledge of the stability of cod climbing in frost according to the season. With increased knowledge of the effects of the season, the quality of raw materials and storage conditions on the stability of the liver in frost, it is possible to ensure that raw materials for further processing are available all year round. This report discusses the effects of the season, bleeding methods and storage temperature on the quality and stability of frozen cod climbs. Evaluation factors included enzymatic activity (free fatty acids) and evolution (primary and secondary subjects' evolution). Seasonality had a significant effect on the chemical composition and enzyme activity of the liver. This was reflected in higher fat content and higher levels of free fatty acids in the liver collected in July compared to liver from April. Frost stability also varied with the time of year as the liver from July was more susceptible to peroxide formation. Different bleeding methods (bleeding and gutting in one go (one step) and bleeding first and then gutting (two steps)) generally had little effect on the chemical composition and enzymatic activity of the liver. The haemorrhage methods, on the other hand, had a significant effect on the formation of a second-stage imagery of frostbite during storage, as the liver from fish bled in 2 steps was less craving compared to the liver from fish bled in one step. Storage temperature and time had a decisive effect on the stability of the livers in frost. Based on the available results, it is recommended to store frozen liver at -25 ° C rather than -18 ° C in order to slow down the damage process.

To our knowledge, there is limited information available regarding the effects of temperature, bleeding method, and seasonal variation on oxidation stability of cod liver during frozen storage. A profound knowledge of cod liver stability during frozen storage is needed to secure the available supply of cod liver for processing all year around. The objective of the present study was therefore to evaluate lipid deterioration during frozen storage of cod liver. The effects of temperature, storage time, bleeding method, and seasonal variation on lipid hydrolysis and oxidation were analyzed. Time of year significantly affected the chemical composition and enzymatic activity of the liver, which was reflected in a higher fat content and higher level of free fatty acids in the liver collected in July compared to liver collected in April. Stability during frozen storage also varied with season where liver from July was more vulnerable towards peroxidation. Different bleeding methods (bleeding and gutting in one step compared to bleeding first and then gutting (two steps)) had significant effect on the lipid oxidation where liver from fish bled in one step turned out to be more rancid compared to liver from fish bled in two steps. Storage temperature and time proved to be important factors with regard to lipid degradation of cod liver during frozen storage. Based on present results, in can be recommended to store frozen liver at - 25 ° C rather than -18 ° C in order to slow down these damage reactions.

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Reports

Research of superchilling of whitefish / Research of superchilling of whitefish

Published:

01/10/2014

Authors:

Gunnar Þórðarson, Albert Högnason, Hólmfríður Sveinsdóttir

Supported by:

Westfjords Growth Agreement

contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Research of superchilling of whitefish / Research of superchilling of whitefish

Five studies were conducted by a research team (supercooling team) in the summer of 2014 to test the effect of supercooling on the processing and product quality of whitefish. This project was based on foreign scientific research on supercooling, which was carried out in laboratories, while the research of the supercooling team was carried out under processing conditions. The results of the research team indicate even more activity than the basic research on which it was based. The main drawbacks were that with supercooling immediately after bleeding and gutting, death stiffness can be significantly delayed, but no damage processes begin until it is completed. It is known that the main reasons for release are rapid death stiffness as the flesh tears with a rapid contraction that clashes with the fish's bone marrow. Fish is 800 times more sensitive than meat and therefore it can withstand very little damage during handling. The results of the supercooling team's research show that during supercooling, the flesh hardens without freezing and withstands all treatments much better, such as filleting, peeling and trimming. Not only is there a difference in the appearance of super-chilled fillets compared to traditional ones, but the proportion of those who went for the most expensive packages was significantly higher. An experiment was carried out at Íslandssaga in Suðureyri and the result was that the increased value due to supercooling was around ISK 900,000 per day. When processing super-chilled fillets for fresh fish export, they were returned in packages at -0.8 ° C while traditional processing was at +2 to + 5 ° C. Freezing part of water in fillets (5‐30%) builds up a high cooling energy that maintains a low temperature throughout the processing (filleting, skinning and trimming). The results of the research team are that with supercooling on board a fishing vessel down to -1 ° C immediately after bleeding and gutting, the use of ice becomes unnecessary for storage in trains and warehouses on land. Trains and cold rooms will be operated at 11 ° C, which is sufficient to maintain supercooling for a long time. Attempts were made to store cod under these conditions for eight days, and the results of research showed that its quality during processing at Fisk Seafood was high and better than with traditional processing.

Five studies were conducted by a research team (superchill ‐ team) in the summer of 2014 to test the effects of superchilling on production and quality of whitefish. This project was based on published studies on superchilling, conducted in laboratories, but the superchill ‐ team conducted their study at industrialized conditions. Conclusion of the research team suggests greater functionality than the scientific researches it was based on. The main conclusion are that super ‐ chilling right after bleeding and gutting can significantly delay rigor mortis, but no spoilage take place before that process. It is well known that the main reasons for gaping in fish fillets are the contraction and relics causing by rigor mortis. Fish is 800 times more sensitive than meat, so it is perishables against handling in processing lines, like filleting, skinning and trimming. One finding in these research is that by super chilling the fish before the process, the flesh is more stiff without being frozen, and can withstand handling in processing much better. The super chilled product is not only looking better compared to the traditional product, but the proportion of more valuable products were significantly higher. A research made in the freezing plant Icelandic Saga in Sudureyri, gave a result were increased value due to super cooling was about 900 thousand ISK per day. In the same trial a temperature for fresh packed fillets for the British market, the product temp for super chill were ‐0,8 ° C, but the traditional product were packed at +2 to +5 ° C. Freezing part of the water content of the fish, around 5‐30%, builds up a massive cooling energy that keeps low temperatures throughout the processing (filleting, skinning and trimming). Results of the research team were thatsuper ‐ cooling fish on board a fishing vessel, down to ‐1 ° C immediately after bleeding and gutting make the use of ice in fish hold redundant. The fish hold need to be run at ‐1 ° C which is sufficient to maintain the super ‐ cooling for a long time. The research team kept whole cod without ice for eight daysin container and ‐1 ° C, with demanding result and extremely good product quality, significantly better than the traditional process.

Report closed until 01.11.2016

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Reports

Effects of bleeding methods on the quality and storage life of cod and saithe products

Published:

01/02/2014

Authors:

Magnea G. Karlsdóttir, Nguyen Van Minh, Sigurjón Arason, Aðalheiður Ólafsdóttir, Paulina E. Romotowska, Arnjótur B. Bergsson, Stefán Björnsson

Supported by:

AVS (R 11 087‐11)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Effects of bleeding methods on the quality and storage life of cod and saithe products

The aim of the project was to examine the effect of different bleeding methods on the quality and shelf life of different cod and saithe products. By identifying ideal conditions for bleeding, gutting and bleeding, it is possible to prevent product defects due to blood and at the same time increase the stability of the products in transport and storage. The fish were either bloodied in the hands and in the machine. Bleeding took place in slush or sea and the effects of different bleeding times were examined. The effect of waiting time on tires before bleeding was also assessed, as well as bleeding and gutting the fish in one step or two steps (gutting performed after bleeding). The products studied in this project were chilled and frozen cod and saithe products, as well as salted cod products. Of the variables studied in this project, their importance differed in terms of which fish species were involved and what the final product was. When comparing comparable sample groups of cod and saithe, it is seen that different conditions are suitable for each species. This supports the theory that it is probably not possible to transfer the best bleeding method of cod to saithe and vice versa. Bleeding time and type of bleeding agent (sludge vs. seawater) had a decisive effect on the stability of the cod and saithe products examined. Cod products, both chilled and frozen, from raw material soaked in sludge generally resulted in improved quality and stability compared to if soaked in seawater. In contrast to cod, the bleeding of saithe into the sea generally resulted in a stable end product. The way the fish were bled and gutted also had a decisive effect on the final products. In the case of frozen cod products, raw and gutted raw material in one step generally yielded a more stable product compared to raw material that was gutted after bleeding had occurred (two steps). Salted products, on the other hand, were much more stable in storage if the raw material was gutted after bleeding. Different results were also obtained for saithe depending on the final product involved. Bleeding and gutting of saithe in a machine had a positive effect on the shelf life of chilled products compared to if made by hand. Machine bleeding and gutting, on the other hand, resulted in a much more unstable product in the cold. The results of the project show that the effects of different bleeding methods are quite dependent on the raw material as well as the final product involved.

The main objective of the project was to study the effects of different bleeding methods on quality and storage life of various cod and saithe products. Products defects due to blood residues can be prevented by optimizing bleeding protocols, and hence increase the quality and storage life of the products. For this, fishes were either bled and gutted by hand or by machine. The bleeding (blood draining) was carried out with seawater or slurry ice, and the effects of different bleeding times in the tanks were also investigated. Moreover, the effects of waiting time (on deck) before bleeding, as well as the procedure of bleeding technique (bleeding and gutting in one procedure vs. gutting after blood draining) were investigated. The various products evaluated were chilled and frozen cod and saithe products, and salted cod products. The importance of the different parameters investigated in this project varied considerably with regard to fish species and the final products. Comparison of parallel treatments groups of cod and saithe demonstrated that optimum bleeding procedures are different for each species. Waiting time on deck and bleeding media (slurry ice vs. seawater) significantly affected the storage life of the cod and saithe products. Cod products, both chilled and frozen, from fish bled in slurry ice generally resulted in improved quality and storage life compared to fish bled in seawater. In contrast to cod, bleeding or saithe in seawater resulted however in more stable products. The procedure during bleeding and gutting also had great impact on the storage life of the various products studied. Shorter storage life of salted cod products was generally observed when the raw material was bled and gutted in one step compared to when gutting was performed after bleeding (two steps). Rather conflicting results were, however, observed for saithe and were depending on the type of final product. Bleeding and gutting of saithe by machine improved the storage life of chilled products compared to when the saithe was bled and gutted by hand. The machine procedure had, however, negative effects on the storage life of the frozen saithe products. Overall, the results of this project indicate that the effects of different bleeding methods are highly relative to fish species as well as the final product of interest.

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Reports

Bleeding system for small vessels

Published:

01/01/2014

Authors:

Sigurjón Arason, Gunnar Þórðarson, Magnea Karlsdóttir, Albert Högnason, Guðbjartur Flosason

Supported by:

Westfjords Growth Agreement, AVS / V12008 / 12

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Bleeding system for small vessels

Extensive research has been carried out on the quality of cod bleeding, all of which indicate that proper handling has a significant effect on product quality. Studies have shown that poorly blooded fish produce worse products, whether it is fish that is processed into fresh, frozen, salted or dried products4. With the increasing influx of smaller boats engaged in longline and handline fishing, there has been a problem with bleeding, as many of them are not equipped with bleeding tanks. Matís' research indicates that fish that are allowed to bleed long enough in high seas, at natural sea temperatures, immediately after bleeding, produce better raw materials than with traditional treatment. A traditional method on board small boats is to bleed the fish directly from the line into the sludge tank on the train. Matís, 3X Technology and Fiskvinnslan Íslandssaga have completed the project "Processing processes of small boats" where conditions on board small boats were examined with a view to designing equipment that was suitable for smaller line boats. The design of the equipment (Rotex bleeding tank FIFO) has been completed and construction has begun at 3X Technology. The aim of this project is to investigate the efficacy of the Rotex method in cod bleeding through an objective study. This work is done in collaboration with 3X Technology, Matís and Jakob Valgeir ehf in Bolungarvík. Samples of cod were taken in two oars of a day rowing boat using different bleeding and finishing methods. Samples were filleted and some of the fillets were then sent fresh to Matís on Vínlandsleið, where different methods were used to assess the quality of the raw materials. The other part was done in the traditional way, ie. production of lightly salted, frozen fillets, and then used to obtain the effect of different bleeding methods on the quality of products during storage in the freezer, for different lengths of time and at different temperatures. The results of the project will support other research in this field and is an important contribution to the discussion on better quality of small boat catches.

Extensive research has been conducted on the quality of bleeding process of cod on board but the correct treatment can have a significant effect on the final product quality. Studies have shown that insufficient bled fish will result in low value products, whether in the case of fresh, frozen or dried production. This problem is mainly related to fish caught by long ‐ line, especially on smaller vessels that are not equipped with necessary equipment for the bleeding process such as bleeding tanks. Researches indicate that bleeding of fish with sufficient flow of fresh seawater in the bleeding tank will result in higher quality products. The traditional bleeding method on board small vessels is to bleed the fish directly in to slush ice tub in the ship convoy. Matis, 3X Technology and Icelandic Saga have finished the research project “Processing in small vessels” where conditions on board the small vessels were examined with the aim to design equipment suitable for smaller long‐ liners. The output of that project was the design of new equipment “Rotex” (bleeding tank FIFO). This was completed and a production was launched by 3X Technology. Samples of cod were collected in two fishing trips from a long liner landing daily, using different methods of bleeding and handling. Samples were filleted and parts of it were sent fresh for research at Matis in Vinlandsleid where different methods were tested considering different product quality and the other parts were prepared with traditional production of lightly salted fillet pieces. The fillets were frozen and used to test the effect of different bleeding methods on product quality after storage in the freezer, using different storing time and different temperatures. The aim of present project was to investigate the effect of the ROTEX bleeding process with an objective researches in collaboration with 3X Technology, Matis and the fish processor and boat owner, Jakob Valgeir Ltd. This project will support other researches in this area as well as to be an important input for disquisition about better quality of small boats catch.

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Reports

Bleeding system for small vessels

Published:

01/02/2013

Authors:

Sigurjón Arason, Gunnar Þórðarson, Magnea Karlsdóttir, Albert Högnason, Guðbjartur Flosason

Supported by:

Westfjords Growth Agreement, AVS / V12008 / 12

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Bleeding system for small vessels

Extensive research has been carried out on the quality of cod bleeding, all of which indicate that proper handling has a significant effect on product quality. Studies have shown that poorly blooded fish produce worse products, whether it is fish that is processed into fresh, frozen, salted or dried products4. With the increasing influx of smaller boats engaged in longline and handline fishing, there has been a problem with bleeding, as many of them are not equipped with bleeding tanks. Matís' research indicates that fish that are allowed to bleed long enough in high seas, at natural sea temperatures, immediately after bleeding, produce better raw materials than with traditional treatment. A traditional method on board small boats is to bleed the fish directly from the line into the sludge tank on the train. Matís, 3X Technology and Fiskvinnslan Íslandssaga have completed the project "Processing processes of small boats" where conditions on board small boats were examined with a view to designing equipment that was suitable for smaller line boats. The design of the equipment (Rotex bleeding tank FIFO) has been completed and construction has begun at 3X Technology. The aim of this project is to investigate the efficacy of the Rotex method in cod bleeding through an objective study. This work is done in collaboration with 3X Technology, Matís and Jakob Valgeir ehf in Bolungarvík. Samples of cod were taken in two oars of a day rowing boat using different bleeding and finishing methods. Samples were filleted and some of the fillets were then sent fresh to Matís on Vínlandsleið, where different methods were used to assess the quality of the raw materials. The other part was done in the traditional way, ie. production of lightly salted, frozen fillets, and then used to obtain the effect of different bleeding methods on the quality of products during storage in the freezer, for different lengths of time and at different temperatures. The results of the project will support other research in this field better quality of catching small boats.

Extensive research has been conducted on the quality of bleeding process of cod on board but the correct treatment can have a significant effect on the final product quality. Studies have shown that insufficient bled fish will result in low value products, whether in the case of fresh, frozen or dried production. This problem is mainly related to fish caught by long ‐ line, especially on smaller vessels that are not equipped with necessary equipment for the bleeding process such as bleeding tanks. Researches indicate that bleeding of fish with sufficient flow of fresh seawater in the bleeding tank will result in higher quality products. The traditional bleeding method on board small vessels is to bleed the fish directly in to slush ice tub in the ship convoy. Matis, 3X Technology and Icelandic Saga have finished the research project “Processing in small vessels” where conditions on board the small vessels were examined with the aim to design equipment suitable for smaller long ‐ liners. The output of that project was the design of new equipment “Rotex” (bleeding tank FIFO). This was completed and a production was launched by 3X Technology. Samples of cod were collected in two fishing trips from a long liner landing daily, using different methods of bleeding and handling. Samples were filleted and parts of it were sent fresh for research at Matis in Vínlandsleid where different methods were tested considering different product quality and the other parts were prepared with traditional production of lightly salted fillet pieces. The fillets were frozen and used to test the effect of different bleeding methods on product quality after storage in the freezer, using different storing time and different temperatures. The aim of present project was to investigate the effect of the ROTEX bleeding process with an objective researches in collaboration with 3X Technology, Matis and the fish processor and boat owner, Jakob Valgeir Ltd. This project will support other researches in this area as well as to be an important input for disquisition about better quality of small boats catch.

Report closed until 01.08.2013

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Reports

Processing in small fishing vessels

Published:

01/03/2012

Authors:

Gunnar Þórðarson, Albert Högnason, Óðinn Gestsson

Supported by:

Technology Development Fund

contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Processing in small fishing vessels

Proper bleeding of catfish can have a significant impact on the quality of the products produced. It has been shown that there can be a big difference in the quality of well-drained fish and bad-blooded fish, and this effect can be observed after freezing of products. In this project, equipment was developed that could be used in small boats, but would ensure that all fish caught on the line receive the same treatment and sufficient time in heavy sea changes during bloodshed. A total of three trips were made with Gesti ÍS, a 10 ton liner made from Suðureyri and made by Fiskvinnsla Íslandssaga. In the last move, a new device, Rotex equipment from 3X Technology, was tested. The result is promising and the crew agreed that the equipment met all their requirements and the result clearly indicates that the quality of landed catch has improved. The ice scraper in the tanks in which the fish is stored until it is processed is clean and clear, but not mixed with blood and contaminated waste from the fish's stomach.

Proper bleeding of cod ‐ fish may have a significant impact on product quality. It has been shown that proper bleeding of fish can have a great difference on product quality, even after the products have been frozen. This project was to design equipments which could be used in small fishing vessels, and would ensure that all long ‐ line catch would receive equal handling regarding to bleeding processes. Three trips were made on Gestur IS, which is a 10 tons long ‐ line fishing vessel operated from Sudureyri and run by Icelandic Saga. The third and last of this test trips, a new equipment from 3X Technology, Rotex mechanism, was tested. The result looks promising and the crew agreed that the machine meets all their requirements and the result gives a clear indication of increased quality of the catch. The slush ice in the fish tubs are kept tide and clean, and devoid of blood water and other smutch from the bleeding operation, often contaminated by guts.

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Reports

Small vessels - Optimizing catch value

Published:

01/12/2010

Authors:

Jónas R. Viðarsson, Sveinn Margeirsson, Sigurjón Arason

Supported by:

AVS (project R 011‐09)

contact

Jónas Rúnar Viðarsson

Head of Value Creation

jonas@matis.is

Small vessels - Optimizing catch value

The catch of small boats has the potential to be the best raw material available, as it is hardly possible to think of a fresher fish than the catch of day-trippers fishing on line or hand gear. Improper handling can, however, have the effect that small-boat fish do not live up to the expectations placed on them, which in turn means that it is not possible to process the catch into the most valuable products. Often, however, relatively small changes in working methods are required to ensure that the catch is under the brand name as a fish of maximum quality. This report discusses the issues that most affect the quality and shelf life of small boat fish, measures and comparisons are made of various influencing factors, reports on the preparation of guidance and incentive material published in connection with the project, and finally proposals are made for improvements in the value chain of small boat fish. The main emphasis in the project was on the preparation and distribution of teaching and instructional material for seafarers. A booklet and leaflets were published and distributed to all small boat fishermen in the country, and it is expected that the result will be reflected in increased knowledge of the importance of good handling of fish. Interested parties can contact Matís and receive the brochure by post, but it is also available on the company's website, ie. www.matis.is/media/matis/utgafa/Mikilvaegi‐godrar‐medhondlunar‐a‐fiski.pdf

The catch of small day ‐ boats using handline or longline has the potentials of being the best available raw material for the production of high value seafood. Improper handling has however often resulted in poor quality of this catch, which makes the products unsuitable for high ‐ end markets. Generally speaking there is however only need for relatively small adjustments in handling procedures in order to allow fish from small day ‐ boats to live up to its potentials as top quality seafood. In this report are discussed various quality issues related to small day ‐ boats. Measurements and comparisons are made between quality factors. Work related to writing, publishing and distribution of an educational brochure and other quality inducing material is accounted for. And finally there are brought forth suggestions on how to improve the value chain of catch from small day‐ boats. The main focus of this project was awarded to publishing practical and easy to understand educational material for fishermen. A brochure and a one ‐ pager were published and distributed to every small vessel in the Icelandic fleet. Hopefully, this educational material will be widely used amongst fishermen and contribute to improved knowledge on the importance of proper handling of seafood. The brochure is available at Matís and online at www.matis.is/media/matis/utgafa/Mikilvaegi‐godrar‐medhondlunar‐a‐fiski.pdf

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Reports

Processing in line boats / Processing in line boats

Published:

01/06/2009

Authors:

Róbert Hafsteinsson, Albert Högnason, Sigurjón Arason

Supported by:

AVS, Technology Development Fund

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Processing in line boats / Processing in line boats

This project is a collaborative project of the following companies; Matís, Brim, Samherji, Vísir and 3X Technology. The aim of the project is to improve the processing processes of longline vessels with a view to reducing the cost of processing, increasing work efficiency and product quality. The project includes the results of a voyage with the icefish trawler Stefni ÍS, where the goal was to perform different refrigeration and bleeding experiments on cod and thus find out what is the best processing method / processing treatment with regard to the quality of the product. The processing deck on longliners will be designed differently, but the same units are used to maximize the quality of the catch. Several groups were taken who received different processing treatments on board. The groups then went to the processing of Hraðfrystihús Gunnvarar where they underwent a sensory evaluation test in the color and release of the fillets. The main results of the project showed that bleeding in the sea, preferably with a lot of water change, before cooling, gives a better color - the meat quality of the wreck. There was no significant difference between the groups in terms of loss, as they all had similar results.

This project is a collaboration work between; Matis, Brim, Samherji, Vísir and 3X Technology. The object of this project is to improve the process in line boats, by reducing production costs, improve working conditions and product quality. This project includes payoff from voyage with the ice-fresh trawler Stefnir ÍS, where the objective was to carry out difference bleeding and cooling methods on cod and find out which methods is efficient regards to the quality of the product. The processing deck in line boats will be implement difference, but same unitary will be used to increase the quality of the catch. The primary conclusion from the research on board Stefnir, is that bleeding in sea before cooling the fish, gives better results regard to the color of the fillet. The research also shows that there was not a significant difference between groups regards to results in looseness of the fillet.

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