Reports

Influence of seasonal variation and frozen storage temperature on the lipid stability of Atlantic mackerel (Scomber scombrus)

Published:

01/12/2016

Authors:

Paulina E. Romotowska, Magnea G. Karlsdóttir, María Gudjónsdóttir, Hörður G. Kristinsson, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund (R 040-12)

Influence of seasonal variation and frozen storage temperature on the lipid stability of Atlantic mackerel (Scomber scombrus)

The effect of the storage temperature (-18 ° C vs. 25 ° C) and the fishing season (August vs. September) on the decomposition of fat in Atlantic mackerel caught off the coast of Iceland were examined in this project. Fat stability was assessed by measuring first-stage (PV) and second-degree evolution (TBARS), free fatty acids (FFA) and fatty acid composition. The results show a significant difference in fat degradation with long-term storage, as the degradation was significantly less when stored at -25 ° C compared to -18 ° C. In addition, fish were caught in September with a higher development value compared to fish from August. On the other hand, the most enzymatic fat breakdown was higher in August than in September. The results also indicated that the amount of omega-3 polyunsaturated fatty acids was fairly stable throughout the storage period. In other words, the results showed that the temperature in the cold store had a great effect on fat breakdown, but the stability depended on when the fish was caught.

Lipid deterioration of Atlantic mackerel (Scomber scombrus) caught in Icelandic waters was studied, as affected by different frozen storage temperatures (-18 ° C vs. -25 ° C) and seasonal variation (August vs. September). The lipid stability was investigated by analyzes of hydroperoxide value (PV), thiobarbituric acid reactive substances (TBARS), free fatty acids, as well as changes in fatty acid composition. Results showed significant lipid deterioration with extended storage time, where the lower storage temperature showed significantly more protective effects. Furthermore, a higher lipid oxidation level was recorded for fish caught in September than in August, although lipid hydrolysis occurred to be greater for fish in August than in September. Moreover, results indicated a rather stable level of omega-3 fatty acid during the entire frozen storage period. The analysis indicated that both lipid oxidation and hydrolysis were affected by the frozen storage temperature and the stability differed with regards to season of catch.

Report closed until 01.01.2018

View report

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.

View report

Reports

Effect of brining and frozen storage on physicochemical properties of well-fed Atlantic mackerel (Scomber scombrus) intended for hot smoking and canning

Published:

01/12/2015

Authors:

Paulina E. Romotowska, María Gudjónsdóttir, Magnea G. Karlsdóttir, Sigurjón Arason, Ásbjörn Jónsson, Hörður G. Kristinsson, Telma B. Kristinsdóttir

Supported by:

AVS Fisheries Research Fund (R 040-12)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Effect of brining and frozen storage on physicochemical properties of well-fed Atlantic mackerel (Scomber scombrus) intended for hot smoking and canning

Mackerel (Scomber scombrus) is a relatively new species off the coast of Iceland. As mackerel is a fatty fish with a short shelf life, it therefore requires maximization of storage conditions and processing processes. In this project, changes in the chemical and physical properties of the heat treatment of salted and unsalted mackerel were studied. Prior to processing, the fish was stored for 6, 9 and 12 months at -18 ° C and -25 ° C with a view to examining how well Icelandic frozen mackerel is suitable as a raw material in canned and hot-smoked products. To examine the effect of heat treatment on the processing properties of mackerel, the samples were heated to 75 ° C (to simulate smoking) and 90 ° C (to simulate canning). Prolonged storage in the freezer had a negative effect on the raw material due to increased development and the fish stored at -18 ° C had a significantly poorer quality compared to fish stored at -25 ° C before processing. The results showed that a product heated to 75 ° C had a higher water content, higher water resistance and higher utilization and was also higher compared to a product heated to 90 ° C. Overall, the results indicate that a fat summer marker could be well suited for the processing of canned and hot-smoked products.

Atlantic Mackerel (Scomber scombrus) is a novel species in Iceland and as a fatty fish with a short shelf-life it requires optimization of storage and processing conditions. Physicochemical changes of brined and un-brined mackerel were analyzed during frozen storage (6, 9, 12 months) at -18 ° C vs. -25 ° C with the aim of investigating the suitability of using well-fed frozen mackerel as raw material for canned and hot-smoked products. Heat treatments to a core temperature of 90 ° C (representing canning) and 75 ° C (representing hot-smoking) were applied. Prolonged frozen storage showed negative effects on the raw material prior to heat processing due to an increased level of lipid oxidation, where fish stored at -18 ° C was of significantly poorer quality than fish stored at -25 ° C. Moreover, the results indicated that heat treatment resulting in a core temperature of 75 ° C showed higher water content, liquid holding capacity, heating yield as well as lower maximum shear force of texture compared to mackerel heated to a core temperature of 90 ° C. Overall, analyzes indicated that the fatty summer mackerel was well suited for the production of canned and hot-smoked products.

Report closed until 01.01.2018

View report

Reports

Improved reefer container for fresh fish - Final report

Published:

01/01/2013

Authors:

Sæmundur Elíasson, Björn Margeirsson, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund, AVS‐Ref.No .: R11 093‐11

contact

Sæmundur Elíasson

Project Manager

saemundur.eliasson@matis.is

Improved reefer container for fresh fish - Final report

The main goal of the project Improved refrigerated container for fresh fish was to improve refrigerated containers and procedures for transporting fresh seafood through redesign and testing. The aim is for design improvements to deliver refrigerated containers that reach a more even temperature throughout the transport process. Efforts should be made to achieve satisfactory improvements to refrigerated containers that are used today with simple and inexpensive measures. The consequences of improved temperature control in production and transport processes are increased quality, stability and safety, which at the same time increase the value of the product. Partners in the project were Matís, the University of Iceland, Eimskip Ísland and Samherji. This report describes the main results and products of the project. The results of the project showed that improvements are needed in maritime transport chains and it was shown that improvements can be achieved with simple and low-cost measures. Temperature control for sea transport can be improved by choosing the target temperature and cooling containers that are best suited for transporting fresh fish products. Mapping the heat distribution of refrigerated containers showed variability both in the transport process and in terms of location within the container, but design improvements aimed at forcing airflow within the container resulted in a more even heat distribution. The importance of procedures for loading refrigerated containers and their handling from manufacturer to buyer was also demonstrated.

The purpose of the project Improved reefer container for fresh fish is to use simple redesign and experimental testing to improve temperature control in reefer containers and work procedures of fresh fish products during transport. The design improvements are aimed at producing a reefer with more stable temperature through sea freight and transport. The aim is to get satisfactory improvements with simple and cost effective procedures. Improved temperature control in fish chill chains leads to increased product quality, stability and safety and thereby increased product value. The project was done in collaboration with Matís, University of Iceland, Eimskip Ísland and Samherji. This report describes the main results and products of the project. The results of the project showed that there is room for improvement in sea transport cold chains and with design improvements experiments it was demonstrated that they can be improved with simple and cost effective procedures. The results showed that the temperature control during sea freight may also be improved by selecting the reefer types most suitable for fresh fish transport and selecting different set point temperatures during summer and winter. The mappings of temperature distribution inside the reefers showed spatiotemporal variability and design improvements achieved a more uniform distribution by means of forced air circulation. Field tests demonstrated the importance of correct operating procedures during loading of reefers and their handling from processor to end location.

View report

Reports

Thermal modeling of processing and transport of fresh fish / Hermun kæliferla - LOKASKÝRSLA

Published:

01/09/2011

Authors:

Björn Margeirsson, Sigurjón Arason, Kristín Valtýsdóttir

Supported by:

AVS Fisheries Research Fund, Technology Development Fund, University of Iceland Research Fund

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Thermal modeling of processing and transport of fresh fish / Hermun kæliferla - LOKASKÝRSLA

The main objective of the project Simulation of cooling processes - thermodynamic simulation of production and transport processes, which began in June 2008, was to present improvements in procedures and equipment related to the transport of marine products through process analysis, experiments and computerized thermal and hydrological models. The consequences of improved temperature control in production and transport processes are increased quality, stability and safety, which at the same time increase the value of the product. Partners in the project were Matís, the University of Iceland, Promens Tempra, Eimskip Ísland, Samherji, Brim (ÚA), Festi, Völusteinn and Eskja. This report describes the main results and products of the project. Examples of products are heat transfer models of fresh fish products in a foam box, which make it possible to predict fish temperatures based on environmental temperature history. Heat transfer models were used to redesign the Promens Tempra 3, 5 and 7 kg foam boxes with the minimum target fish temperature minimization under the target heat load. Experiments confirmed the superiority of the new boxes over traditional box types, both in terms of temperature control and product quality under heat load. The results of another experiment show that the shelf life of fresh fish fillets in corner boxes of whole pallets in the air transport chain can be about 1-1.5 days shorter than fillets in boxes in the middle of the pallet stack. Heat distribution in different cooling chains was mapped and special emphasis was placed on pre-cooling fillets for packing and heat distribution in different types of cooling containers with different loading patterns. 

The main aim of the research project Hermun kæliferla - Thermal modeling of processing and transport of fresh fish, which was launched in June 2008, was to improve technology and practices used for fish processing and transport by means of analysis of chill chains, experiments and computational modeling. Improved temperature control in fish chill chains leads to increased product quality, stability and safety and thereby increased product value. This report describes the main results and products of the project. Examples include heat transfer models of fresh fish fillets packaged in boxes, which can be used to predict product temperature evolution as a function of variable ambient temperature. Numerical heat transfer models were used to optimize the design of 3, 5 and 7 ‐ kg expanded polystyrene boxes manufactured by Promens Tempra with the aim of minimizing the maximum fish temperature in boxes under thermal load. Improved thermal protection of the new box design was confirmed in different experiments, both with regard to lesser product temperature variations and extended freshness period and storage life of products. The results from another storage study suggest that the storage life of fresh fish products in a corner box can be more than 1‐1.5 days shorter than in the center boxes of a full size pallet stack in a real air transport chain, depending on the level of ambient thermal load. Environmental and product temperatures were mapped in different chill chains with special emphasis laid on precooling during processing and temperature distribution in reefer containers of different types and loading patterns. 

View report

Reports

Optimized Chilling Protocols for Fresh Fish

Published:

01/12/2010

Authors:

Björn Margeirsson, Hélène L. Lauzon, Lárus Þorvaldsson, Sveinn Víkingur Árnason, Sigurjón Arason, Kristín Líf Valtýsdóttir, Emilía Martinsdóttir

Supported by:

AVS R&D Fund of Ministry of Fisheries in Iceland, the Technology Development Fund at the Icelandic Center for Research, University of Iceland Research Fund and EU (contract FP6-016333-2)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Optimized Chilling Protocols for Fresh Fish

Guidelines for cooling fresh fish describe the most effective cooling methods at all stages of the cooling chain, with an emphasis on white fish. It describes how to best cool and maintain temperatures in order to maximize product quality and safety and reduce costs and energy consumption. The report contains background information for instructions in the information source Kæligátt on Matís' website, which is presented in a user-friendly way in Icelandic www.kaeligatt.is and English www.chillfish.net. The guidelines are intended for fishermen, manufacturers, carriers and other members of the value chain. The guidelines are based on research that has been carried out within research projects such as Chill ‐ on, Simulation of cooling processes and Cooling improvement. The main chapters deal with refrigeration on board, during processing, during packing, transport and storage of fish.

The overall aim of the optimized chilling protocols is to describe the most effective chilling methods for any stage in the food supply chain with emphasis on whitefish. This comprises optimization of the whole chain for lowering and maintaining low temperature with the aim of maximizing quality and safety of the products and minimizing costs and energy use. This report is the background for the protocols and guidelines published with open access at Matís website in Icelandic and English in a user ‐ friendly way: www.chillfish.net. These are protocols to follow aimed at the use of fishermen, manufacturers, transporters and other stakeholders in the fisheries chain. The information is divided into subchapters of different links in the chain. How to chill fish on ‐ board, during processing, packaging, transport and storage are the main chapters.

View report
en_GBEnglish