Reports

Chemical composition of silver - Seasonal fluctuations

Published:

26/08/2019

Authors:

Þóra Valsdóttir, Karl Gunnarsson

Supported by:

Fisheries Project Fund, AVS

contact

Þóra Valsdóttir

Project Manager

thora.valsdottir@matis.is

Chemical composition of silver - Seasonal fluctuations

The aim of the study was to examine the amount of nutrients, minerals and trace elements in oats by season to assess when it is best to harvest them from a nutritional point of view. Samples were taken at two locations, Tjaldanes by Saurbær in Dalasýsla and Herdísarvík by Selvogur in Reykjanes in the period from October 2011 to April 2013.

Seasonal fluctuations were detected in the content of nutrients in silver in both Herdísarvík and Tjaldanes and then followed the same process. In early spring, fiber, protein, fat, ash and water levels peaked. Measurements also indicated seasonal fluctuations in some of the minerals and trace elements measured; potassium, phosphorus, iodine, selenium, cadmium and lead. Heavy metals were within the limit limits with the exception of cadmium in winter.

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Reports

Seasonal and geographical variation in chemical composition and lipid stability of Atlantic mackerel (Scomber scombrus) caught in Icelandic waters

Published:

01/12/2015

Authors:

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

Supported by:

AVS Fisheries Research Fund (R 040-12)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Seasonal and geographical variation in chemical composition and lipid stability of Atlantic mackerel (Scomber scombrus) caught in Icelandic waters

During the time that mackerel is off the coast of Iceland, it is eaten a lot, which causes it to gain weight quickly, with the result that the meat becomes very sensitive to handling. In this study, mackerel caught in the summer seasons of 2012 and 2013 (July, August, September) and from different fishing areas (east, northeast, south and southeast) were examined. In order to assess how well the raw material is suitable for processing high-quality products for human consumption, the mackerel was measured in terms of water and fat content, fatty acid composition, color, coloration and free fatty acids. In general, the mackerel collected in the summer of 2012 was of better quality than mackerel from 2013. The results also indicated a variability between fishing months in terms of fat content and the progress of development. Mackerel caught in the middle of the season had the lowest developmental value, indicating that this mackerel is best suited for processing high-quality products for human consumption.

Atlantic mackerel (Scomber scombrus) appears in Icelandic waters during its heavy feeding period, resulting in variation in mackerel products quality. Fish caught at different season during the summers of 2012 and 2013 (July, August, September) and at different sites of the Icelandic fishing area (East, Northeast, South and Southeast) were analyzed. Measurements of lipid and water content, fatty acid composition, color changes, lipid hydroperoxide (PV), thiobarbituric reactive substances (TBARS) and free fatty acid (FFA) were studied with the aim of investigating whether this raw material was suitable for the production of high quality products for human consumption. In general, samples collected during the summer of 2012 showed a better condition than fish from 2013. The results indicated seasonal variation in lipid content and rancidity development. The lowest rancidity values were observed in the middle of the Icelandic catching season, indicating that this raw material was best suited for production of high quality products. Moreover, geographical variation of the mackerel catches had an impact on the saturation of the fatty acids, and appeared as follows: East> Southeast> Northeast> South.

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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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