Reports

The effects of food container depth and coverage on the quality of superchilled rainbow trout

Published:

01/09/2018

Authors:

Magnea Karlsdóttir, Erwan Queguiner, Björn Margeirsson, Sigurjón Arason, Aðalheiður Ólafsdóttir

Supported by:

AVS R&D Fund (R 17 016-17), Technology Development Fund (164698-1061)

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

The effects of food container depth and coverage on the quality of superchilled rainbow trout

Fresh farmed fish is generally gutted and packed in a foam plastic box with ice for export in refrigerated containers. In view of the great development that has taken place in terms of supercooling and its positive effect on the quality of fish products, other more cost-effective and environmentally friendly packaging solutions have been examined, including insulated food containers. The main objective of the project was to evaluate the impact of different packaging methods on the quality of fresh rainbow trout. Gutted fish with a head was packed in a foam plastic box and insulated pots of different depths (29-60 cm). In addition to comparing different depths of pots, different embodiments of closing pots were also examined. Experimental fish were observed at the top and bottom of each tank. The pots were stored in a temperature-controlled environment at about -1 ° C and measurements were made after 8 and 13 days after packing. The fish packed in a foam box was either supercooled before packing or cooled in the traditional way with ice. This was done to assess the effect of supercooling on fresh rainbow trout. To assess the quality of the rainbow trout, microbial growth, texture and release in fillets were monitored. The results showed that the packaging solutions examined in the project had a relatively small effect on the total number of microorganisms, but there was no significant difference between experimental groups at the end of the storage period. In general, there was little to no difference between groups in texture and texture in fillets. On the other hand, the results showed that it is necessary to close the pots, but the type did not have a significant effect. Supercooling before packing had a significant effect on release. Fish that was cooled in the traditional way and packed in a foam plastic box with ice had significantly more release compared to when it was super-cooled and packed in a pot or foam plastic box without ice. The results show that there is no significant difference between foam boxes and pots of different depths compared to the quality variables examined in this project. They indicate that the transport of supercooled rainbow trout in pots is a viable option in terms of the stability of the raw material and the quality of the product.

The overall aim of the study was to explore the effects of different packaging solutions on the quality of fresh rainbow trout. Different packaging methods included expanded polystyrene boxes (EPS), insulated food containers of 29 to 60 cm depth with various combination of covers. Each container was split up into two groups, top- and bottom layer. Both fish chilled on ice and superchilled fish were considered. Microbial growth and sensory characteristics (fillet gaping, softness and elasticity) were used to evaluate the quality of the rainbow trout fillets after 8 and 13 days of storage at around -1 ° C. The different packaging solutions had no effects on the microbial quality of the fish. Moreover, no listeria activity was detected. Sensory evaluation showed minor differences between containers of different depths and / or EPS boxes, as well as between top and bottom layers. However, the presence of cover proved to be of great importance, but the type of cover turned out to be not relevant. The effects of superchilling before packaging on fillet gaping was evident in present study since fish packed in EPS box with ice resulted in more gaping than superchilled fish packed in EPS boxes and / or containers without ice.

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Reports

The effects of insulated tub depth on the quality of iced Atlantic cod / Effect of insulated tub depth on the quality of frozen cod

Published:

01/04/2018

Authors:

Rúnar Ingi Tryggvason, Magnea Karlsdóttir, Björn Margeirsson, Sigurjón Arason, Aðalheiður Ólafsdóttir

Supported by:

AVS R&D Fund (R 17 016-17), Technology Development Fund (164698-1061)

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

The effects of insulated tub depth on the quality of iced Atlantic cod / Effect of insulated tub depth on the quality of frozen cod

The aim of the project was to investigate the quality of cod that had been gutted one day after fishing, frozen and packed in 12 different sized tanks, 4 × 250 L, 4 × 460 L and 4 × 660 L. Experimental fish were monitored at the top and bottom of each tank . The pots were stored in a temperature controlled environment at 1 ° C and measurements were made after 6, 10, 13 and 15 days after packing. To assess the quality of the cod, water loss was used in tanks after storage, processing utilization and sensory evaluation. The results showed that water loss was highest in 660 L pots and lowest in 250 L pots. There was no difference in processing efficiency. In all cases, there was less looseness in the bottom of the pot compared to the top, probably due to the different size of fish in the top and bottom. There was no difference in the results of the quality factor (QIM) evaluation between pots, but the existing sensory evaluation scales do not include the properties on which a clear difference was seen. There was a big difference between fish in the top layer and fish in the bottom layer in all cases, but ice vessels and marine fillets were more bulky on bottom fish. As a follow-up to the experiment, a new sensory evaluation scale will be designed in ongoing research on the quality of frozen and supercooled fish in different large tanks, which will address these factors, ie. let's go for ice cream and bruises in fillets.

The aim of this project was to examine the quality difference of Atlantic cod that had been iced and packed into 12 different sized food containers (tubs), 4 × 250 L, 4 × 460 L and 4 × 660 L. Each tub was split up into two groups, top-and bottom layer. Drip loss, processing yield, and sensory evaluation were used to evaluate the quality of the cod. The results showed that the greatest drip loss was in the 660 L tub, and the least in the 250 L tub. There was no difference in processing yield. Sensory evaluation showed no difference between tubs, except that the fillets from fish in the bottom layer of all containers had less gaping than fillets from the top layer of fish, most likely due to size differences of top-and bottom layer fish. No current sensory evaluation scales account for different amounts of ice marks and crushed fillets that was detected between fish in the top-and bottom layer of the tubs. The results of this project will be used in continuing research of iced and superchilled fish in different sized containers to develop a new sensory scale that will account for these qualities.

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Reports

Overview of available methods for thawing seafood / Solutions available for thawing seafood

Published:

01/06/2017

Authors:

Sigurður Örn Ragnarsson, Jónas R. Viðarsson

Supported by:

The Norwegian Research Council (Project number 233709 / E50)

Overview of available methods for thawing seafood / Solutions available for thawing seafood

There is a constant demand for quality raw materials that can be used for producing seafood products for high paying markets in Europe and elsewhere in the world. Suppliers of demersal fish species in the North Atlantic are now meeting this demand by freezing the mainstay of their catches, in order to be able to have available supplies all year around. This is partly done because of seasonal fluctuations in catches, which are harmful from a marking point of view. The fact that all these raw materials are now frozen demands that methods used for freezing and thawing can guarantee that quality of the raw material is maintained. There are a number of methods available to thaw fish. The most common ones involve delivering heat to the product through the surface, as with conduction or convection. These methods include water and air-based systems. More novel methods are constantly on the rise, all with the aim of making the process of thawing quicker and capable of delivering better products to the consumer. These procedures are however, often costly and involve specialized workforce to control the process. All in all, it depends greatly on what kind of conditions a company is operating under regarding which thawing methods should be chosen. This report identifies the most common methods available and provides information on their main pros and cons.

There is a constant demand from fish processing plants around the world for good raw materials from the North Atlantic for the production of products for demanding markets. To meet this demand and in view of the large seasonal fluctuations in catches of certain fish species, companies have decided to freeze the raw material for later use. This requires good methods for freezing the raw material, but it is no less important that the thawing of the raw material is good. There are many methods for thawing fish and other seafood. It has been most common to use heat transfer through surfaces with heat transfer or thermal conductivity. These methods are mostly based on the use of water or air as a medium for thawing. Newer methods exist that try to make the process faster and thus deliver a better product to consumers. However, these methods are often costly and involve a great deal of staff specialization. After all, it matters what kind of business it is and how the companies' situation is at any given time when thawing methods and technical solutions are chosen. This report identifies all the major thawing methods and the technical solutions available on the market today, as well as outlining their main advantages and disadvantages.

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Reports

Thawing of frozen cod fillets

Published:

31/10/2016

Authors:

Ásbjörn Jónsson, Magnea Karlsdóttir, Einar Sigurðsson, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Thawing of frozen cod fillets

The aim of the project was to study methods for thawing cod fillets in blocks and to find the best and possible method for thawing for markets abroad. The result of the project is to lead to an increase in the quality of products made from frozen raw materials and streamlining of processing which leads to lower production costs. It was also found that the method of tempering (semi-thawing) was realistic, provided that the temperature and time of thawing were adjusted.

The object of the project was to explore methods for thawing of seafrozen codfillets and find the potential methods for thawing. The culmination of the project is to lead to increased quality of products derived from frozen fillets and rationalization of processing, resulting in lower production costs. The main results showed that the best method, of the methods tested, was thawing in water with air circulation. It was also revealed that tempering was realistic, provided to adjust the temperature and time of thawing.

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Reports

Northern Cereals - New Opportunities

Published:

27/05/2016

Authors:

Ólafur Reykdal, Sæmundur Sveinsson, Sigríður Dalmannsdóttir, Peter Martin, Jens Ivan í Gerðin, Vanessa Kavanagh, Aqqalooraq Frederiksen, Jónatan Hermannsson

Supported by:

NORA, the Nordic Atlantic Cooperation. NORA project number 515-005

Contact

Ólafur Reykdal

Project Manager

olafur.reykdal@matis.is

Northern Cereals - New Opportunities

A project on grain farming in the Arctic was carried out between 2013 and 2015. The project was funded by the Nordic-Atlantic Co-operation (NORA). Participants came from Iceland, Northern Norway, the Faroe Islands, Greenland, Orkney and Newfoundland. The purpose of the project was to support grain farming in sparsely populated Nordic areas by testing different barley crops and providing guidelines for farmers and food companies. The most promising barley crops (Kría, Tiril, Saana, Bere, NL) were tested with all participants and measurements were made on yield and quality. The amount of barley harvest varied between regions and years. The average starch content of dried grain was 58%, which is sufficient for the baking industry. Fungal toxins (Mycotoxin) were not detected in the samples sent for analysis. It was concluded that early grain sowing was the most important factor in promoting a good grain harvest in the NORA area. Unit is important to cut the grain early to prevent losses due to storms and birds.

A project on the cultivation of cereals in the North Atlantic Region was carried out in the period 2013 to 2015. The project was supported by the Nordic Atlantic Cooperation (NORA). Partners came from Iceland, NNorway, Faroe Islands, Greenland, Orkney and Newfoundland. The purpose of the project was to support cereal cultivation in rural northern regions by testing barley varieties and providing guidelines for farmers and industry. The most promising barley varieties (Kria, Tiril, Saana, Bere and NL) were tested in all partner regions for growth and quality characteristics. Grain yields were very variable across the region and differed between years. Average starch content of grain was about 58% which is sufficient for the baking industry. Mycotoxins, toxins formed by certain species of mold, were not detected in selected samples. Early sowing was concluded to be the most important factor for a successful cereal production in the North Atlantic region. Early harvest is recommended in order to secure the harvest before it becomes vulnerable to wind and bird damages, even though the grain will be slightly less mature.

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Reports

Effect of salt content in slurry ice on quality of fresh and thawed Atlantic mackerel (Scomber scombrus)

Published:

01/12/2015

Authors:

Paulina E. Romotowska, Björn Margeirsson, Gísli Kristjánsson, Sigurjón Arason, Magnea G. Karlsdóttir, Sæmundur Elíasson, Arnljótur B. Bergsson

Supported by:

AVS Fisheries Research Fund (R 12 029-12)

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Effect of salt content in slurry ice on quality of fresh and thawed Atlantic mackerel (Scomber scombrus)

The aim of the experiment was to improve methods of cooling and storage of fresh produce in order to improve the quality of frozen mackerel products. A comparison was made of cooling in conventional ice scrapers and salt-improved ice scrapers. By adding salt to the ice scraper, it was hoped that the temperature of fresh mackerel could be lowered and thus its quality maintained longer. The fresh mackerel was stored for up to seven days after fishing. Another aim of the study was to investigate whether this different cooling of fresh mackerel affects the deterioration of the quality of frozen mackerel products. The results showed that the temperature distribution in the pots was related to salt concentration as lower temperatures were obtained in pots with higher salt content (3.3%). On the other hand, the cold storage had a much greater effect on the quality factors such as the freshness and release of the mackerel products compared to the effect of pre-cooling, as the effect of different salt concentrations in the ice scraper was negligible in terms of these quality factors.

The present experiment is part of the research project - Increased value of mackerel through systematic chilling. The aim of this study was to improve methods of chilling and storing of fresh products in order to obtain better quality of frozen mackerel products. This project was carried out to develop slurry ice mixture with addition of extra salt, with the intention of temperature decrease during chill storage up to seven days after catch. Secondary objective of this research was to investigate if different chilling condition of fresh fish has an effect on the quality assignment of long-term frozen mackerel products. The results showed that temperature distribution in the tubs was correlated to the salt concentration where lower temperature was obtained in the tub with higher salt content (3.3%). Furthermore, freshness, gaping and peritoneum deterioration have been affected by the storage process but not by different salt concentration in slurry ice during chilled storage. Due to high quality variation within the same group of the mackerel is needed to conduct more methods for quality evaluation such as oxidation analysis and sensory analysis.

Report closed until 01.01.2018

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Reports

Effects of temperature fluctuations during storage and transport on quality and stability of frozen mackerel products

Published:

01/12/2015

Authors:

Magnea G. Karlsdóttir, Paulina E. Romotowska, Sigurjón Arason, Ásbjörn Jónsson, Magnús V. Gíslason, Arnljótur B. Bergsson

Supported by:

AVS Fisheries Research Fund (R 040-12)

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Effects of temperature fluctuations during storage and transport on quality and stability of frozen mackerel products

The aim of the project "Maximizing the quality of frozen mackerel products" is to study the quality and stability of mackerel products in frost according to the seasons and the effects of different pre-cooling, freezing and storage conditions. By looking at the interplay of these factors, it is possible to maximize the quality and utilization of mackerel and therefore at the same time its value. This is the first report from the project and it deals with the effects of temperature fluctuations during storage and transport on the quality and stability of frozen mackerel products. Evaluation factors included release, enzyme activity and evolution. Containers were transported to Japan. Whole frozen raw materials provided in late July and early September were frozen and stored at -25 ° C for one month. During "transfer", the product was stored at -18 ° C ± 5 ° C for one month. The samples were measured before freezing, after the "transfer", and thereafter every 3 months in storage at -25 ° C. For comparison, samples were stored at a constant temperature (-25 ° C). In addition, whole frozen mackerel products were stored for up to 12 months at -18 ° C as well as -15 ° C to assess the effects of different storage conditions. There was a clear difference in the quality and stability of frozen mackerel products that were stored at low and stable temperatures compared to products that were subjected to heat stress, for example due to container transport. The results show that mackerel should not be stored above - 25 ° C.

The aim of the project “Quality optimization of frozen mackerel products” is to study the quality and stability of mackerel products during frozen storage as affected by season, different pre-cooling methods, freezing techniques and storage conditions. This is the first report from the project and describes the effects of temperature fluctuations during storage and transportations on quality and stability of frozen mackerel products. The main attributes investigated were eg gaping, enzymatic activity and rancidity. Container shipment were simulated. Whole mackerel caught late July and early September was frozen and stored at -25 ° C for one month. During “transportation”, the products were heat abused at -18 ° C ± 5 ° C for one month. Samples were analyzed after freezing, the transportation and with 3 months interval during subsequent storage at -25 ° C. For comparison, samples were stored at stable temperature (-25 ° C). Additionally, frozen mackerel products were stored for up to 12 months at -18 ° C and -15 ° C to further evaluate the effects of storage temperature. A significant difference in quality and stability were detected between products stored at stable and low temperature and products that underwent heat abuse during eg transportation. The results demonstrate that frozen mackerel products should not be stored at higher temperatures than -25 ° C.

Report closed until 01.01.2018

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Reports

Chitosan treatments for the fishery industry - Enhancing quality and safety of fishery products

Published:

01/04/2015

Authors:

Hélène L. Lauzon, Eyjólfur Reynisson, Aðalheiður Ólafsdóttir

Supported by:

AVS (contract R 13 099-13)

Contact

Aðalheiður Ólafsdóttir

Sensory evaluation manager

adalheiduro@matis.is

Chitosan treatments for the fishery industry - Enhancing quality and safety of fishery products

This report is a summary of three shelf life experiments in which seafood was treated with different chitosan solutions, either on board a fishing vessel (with shrimp and cod) or after slaughter and pre-processing of farmed salmon. This is a continuation of Matís 'report 41-12 where chitosan solutions were developed and tested on different fish products at Matís' experimental stage. The purpose of this project was to confirm the possibility of chitosan treatment of seafood in the fishing industry. The results show that the concentration of chitosan solutions and the storage temperature of seafood affect the antimicrobial activity and the deterioration of the quality of the fish products. Solutions A and B had limited activity in whole shrimp (0-1 ° C), but slower color changes occurred as the shell took on a black color. Treatment of salmon (1.4 ° C) and cod (-0.2 ° C) with solutions C and D significantly slowed the growth of erythrocytes during the first 6 days, leading to a prolongation of the freshwater phase. The storage temperature of cod fish affected the effectiveness of the solutions. When cod (2-3 ° C) was stored in worse conditions and filleted 6 days after treatment, there was a slightly lower microbial load on the fillets at the beginning of the storage period, which resulted in a slight improvement in the quality of the products. Better storage conditions are necessary to limit the effectiveness of chitosan treatment.

This report evaluates the efficiency of different chitosan treatments (A, B, C, D) when used by fishery companies, aiming to reduce seafood surface contamination and promote enhanced quality of fishery products: whole cod, shrimp and farmed salmon. The alkaline conditions establishing in chilled raw shrimp during storage (0-1 ° C) is the probable cause for no benefits of chitosan treatments A and B used shortly after catch, except for the slower blackening of head and shell observed compared to the control group . On the other hand, salmon treatments C and D were most effective in significantly reducing skin bacterial load up to 6 days post-treatment (1.4 ° C) which inevitably contributed to the extended freshness period (by 4 days) and shelf life observed. Similarly, freshness extension and delayed bacterial growth on skin was evidenced after 6 days of storage in whole cod (-0.2 ° C) treated with solution D. For cod stored at higher temperature (2-3 ° C) and processed into loins on days 3 and 6 posttreatment, a slower microbial deterioration was observed only during early storage of loins. The contribution of chitosan treatments to sensory quality enhancement was not clearly demonstrated in these products. Based on the findings, better chilling conditions should contribute to an enhanced effect of chitosan skin treatment towards quality maintenance.

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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

Gæðasalt í saltfiskverkun / Quality salt for curing of salted fish

Published:

01/02/2013

Authors:

Ásbjörn Jónsson, Aðalheiður Ólafsdóttir, Helgi Sigurjónsson, Egil Þórir Einarsson, Kristín Anna Þórarinsdóttir, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund (R 11 088‐11) and Tækniþróunarsjóður Ísl. A former user Italy (110667‐0611)

Contact

Aðalheiður Ólafsdóttir

Sensory evaluation manager

adalheiduro@matis.is

Gæðasalt í saltfiskverkun / Quality salt for curing of salted fish

The main goal of the project was to use the geothermal sea in Reykjanes for the production of salt that can be used to produce high quality salted fish. A process will be developed to produce the salt with geothermal energy on site and to be able to control its chemical composition so that the correct effect of salted fish can be ensured. Salt extracted from the geothermal sea was compared with imported salt from the Mediterranean during the production of salted cod fillets with brine as pre-salting stage and dry salting at the end. The results showed that higher utilization was obtained in the salted fish processing with salt extracted from the geothermal sea, and that the processing took less time as the uptake of salt into the cod muscle was higher compared to the imported salt. Salt extracted from the geothermal sea was comparable in quality to the imported salt.

The aim of the project was to utilize raw material and energy from a geothermal brine to produce salt which can be used to increase the value in production of salted fish. Imported salt from Tunis was compared with the salt from geothermal brine, by producing salted cod from pickle salting followed by dry salting. The results showed that higher yield was observed in production of salted fish, by using salt produced from geothermal brine. Also curing took less time where the penetration of salt in the cod muscle was faster compared to the imported salt. The salt produced from geothermal brine is comparable with the imported salt.

Report closed until 01.02.2015

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