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

Properties of silver. Impact of location and season / Properties of dulse. Influence of location and season

Published:

06/06/2011

Authors:

Þóra Valsdóttir, Karl Gunnarsson

Supported by:

AVS

contact

Þóra Valsdóttir

Project Manager

thora.valsdottir@matis.is

Properties of silver. Impact of location and season / Properties of dulse. Influence of location and season

This report reports on the results of a study of silver collected from June to October 2010 at two different growth sites of silver, on cliffs and boulders (Bolaklettar) and on islands (Fossárvík). The aim was to obtain reliable information on the effect of location and time of year on the appearance, nutritional value, amount of trace elements and minerals in silver in these places. The effect of season and location was measured on most of the measures analyzed, both composition and properties. The degree of variability varies depending on the factor involved. In some cases it can be significant and therefore important to collect silver in the places and time of year that is most favorable.

Dulse was collected from June to October 2010 at two different locations, rocky shore and at sandbank were the sea was mixed with fresh water. The aim was to collect data on the influence of location and season on the appearance and chemical composition of dulse. Significant differences were found on several attributes. Knowledge of the variability in ie color and protein content assist processors in selecting the most favorable raw material for their product.

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Reports

Process control for fishing, processing and processing of salted fish. Impact of raw material variables on the utilization and quality of salted fish

Published:

01/08/2007

Authors:

Lárus Þorvaldsson, Þóra Valsdóttir, Sigurjón Arason, Kristín Anna Þórarinsdóttir

Supported by:

AVS, Rannís Technology Development Fund

contact

Þóra Valsdóttir

Project Manager

thora.valsdottir@matis.is

Process control for fishing, processing and processing of salted fish. Impact of raw material variables on the utilization and quality of salted fish

Data was collected from Vísir hf. and Þorbjörn hf. and the relationship between utilization and quality with fishing areas, fishing time, fishing vessels, cooling on board and changes in the processing process are assessed. It was found that fishing areas had a significant effect on processing utilization, but the difference in effect utilization and quality by fishing area was smaller. Fluctuations in efficiency and quality proved to be seasonal and there was also a difference between years. Changes in cooling on board, ie. the use of liquid ice instead of flake ice on board did not prove to have a significant effect in the aforementioned manner. On the other hand, changes in the mechanism of action, ie. injection, both utilization and quality. The content of the report was part of the project "Process management for fishing, processing and processing of salted fish".

Analysis of data collected by the fisheries companies Vísir and Thorfish revealed the effects of fishing grounds, season, fishing vessels, chilling methods on board and salting procedure on yield and quality of salted products. Effects of fishing grounds on processing yield were significant but curing yield and quality were less influenced. Variation in curing yield and quality were seasonal and differences between years were observed. Changes in chilling methods on-board, ie use of liquid ice instead of flake ice did not affect yield and quality of salted products. On the other hand, changes in the salting procedure did, when injection was added as the initial step in the process.

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