Reports

Increased quality and stability of frozen herring products

Published:

30/08/2019

Authors:

Magnea Karlsdóttir, Huong Thi Thu Dang, María Guðjónsdóttir, Ásbjörn Jónsson, Sigurjón Arason

Supported by:

AVS R&D Fund

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Increased quality and stability of frozen herring products

Freezing and frozen storage has proven to be an effective method to preserve and prolong the storage life of seafood products. Production of frozen products provides all year around product availability although the catching is seasonal. There are several factors that can affect the quality and stability of frozen fish products, including the state of the raw material, processing methods and storage conditions.

The aim of the study was to explore how the physicochemical properties of frozen herring fillets are affected regarding the state of the raw material during processing as well as storage conditions. Atlantic herring was processed and frozen pre- and post-rigor and stored at stable (-25 ° C) and abused storage conditions. To investigate the storage stability and physical properties of the fillets, thawing drip, cooking yield and color were evaluated, as well as proximate composition, fatty acid composition, pH and lipid degradation of the light and the dark muscle.

The study demonstrated the importance of stable and controlled temperature during storage and transportation of frozen herring products. Processing and freezing pre-rigor, in combination with stable storage conditions, was shown to be beneficial in terms of preventing lipid oxidation, as well as reducing thawing loss and maintaining the cooking yield of the herring fillets.

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Reports

Increased quality and stability of frozen herring products

Published:

01/11/2018

Authors:

Magnea Karlsdóttir, Huong Thi Thu Dang, María Guðjónsdóttir, Sigurjón Arason, Ásbjörn Jónsson

Supported by:

AVS R&D Fund (R 069-14)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Increased quality and stability of frozen herring products

Freezing and cold storage is an effective method of maintaining quality and extending the shelf life of seafood. The production of frozen products equals the supply of products where fishing is seasonal. There are many factors that can affect the quality and stability of frozen products. These include the condition of the raw material, processing methods and conditions for storage and transport, to name but a few. The aim of the study was to investigate the changes that take place in the chemical and physical properties of frozen herring fillets with regard to the condition of raw materials during processing and conditions in cold storage. Atlantic herring was processed before and after death solidification, and the fillets were stored under stable storage conditions (-25 ° C) and unstable conditions (at -25 ° C for 2 months, then -12 ° C for one month and then again at - 25 ° C for the duration of storage). To study the stability and physical properties of the products, water loss (drip), boiling efficiency and color were measured, in addition to which both light and dark fish muscles were measured for water resistance, pH, chemical composition, fatty acid composition, enzyme activity and evolution. The study showed that it is important for the fishing industry to ensure uniform and correct temperature control when products are stored in the freezer. Processing and freezing before death solidification, in parallel with stable storage conditions, has a positive effect on the quality and stability of herring falcons. In addition, the study confirmed that the fatty state of the herring muscle, often referred to as the dark muscle, is very sensitive to development. In order to extend the shelf life of frozen herring fillets, it is recommended that this muscle be removed in parallel with deep skinning.

Freezing and frozen storage has proven to be an effective method to preserve and prolong the storage life of seafood products. Production of frozen products provides all year around product availability although the catching is seasonal. There are several factors that can affect the quality and stability of frozen fish products, including the state of the raw material, processing methods and storage conditions. The aim of the study was to explore how physicochemical properties of frozen herring fillets are affected with respect to the state of the raw material during processing as well as storage conditions. Atlantic herring was processed and frozen pre- and post-rigor and stored at stable (-25 ° C) and abused storage conditions. To investigate the storage stability and physical properties of the fillets, thawing drip, cooking yield and color were evaluated, as well as proximate composition, fatty acid composition, pH and lipid degradation of the light and the dark muscle. The study demonstrated the importance of stable and controlled temperature during storage and transportation of frozen herring products. Processing and freezing pre-rigor, in combination with stable storage conditions, was shown to be beneficial in terms of preventing lipid oxidation, as well as reducing thawing loss and maintaining the cooking yield of the herring fillets.

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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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