Reports

Quality optimization of frozen redfish products

Published:

21/02/2020

Authors:

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

Supported by:

AVS R&D Fund (R 029-15)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Maximizing the quality of frozen redfish products / Quality optimization of frozen redfish products

The aim of the study was twofold. Firstly, to explore the influence of time and temperature during frozen storage on lipid deterioration of red fish. That was done by comparing the effect of temperature fluctuation and abuse during frozen storage, as can be expected during transportation, on the physicochemical characteristics and lipid stability of redfish fillets. Secondly, to investigate the effect of 4 days postcatch and 9 days postcatch, and seasonal variation on the quality and storage stability of frozen red fish.

Storage temperature and storage time affected the physical- and chemical properties in redfish, eg free fatty acids, TBARS and TVB-N. Season of capture affected both the nutritional value and stability of golden redfish. The light muscle of fish caught in November was richer in EPA and DHA than in the fish caught in June. The fish caught in November was also more unstable through frozen storage, due to a more unsaturated nature of the fatty acids present, indicating that special care needs to be applied during handling and treatment of golden redfish caught at this time. The light muscle had a higher nutritional value than the dark muscle and is a good nutritional source for human consumption. However, the dark muscle was prone to lipid oxidation which may have a negative influence on the more valuable light muscle. So there seems to be a need to separate them.

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Reports

Styrene migration from expanded polystyrene boxes into fresh cod and redfish at chilled and superchilled temperatures

Published:

01/12/2017

Authors:

Erwan Queguiner, Björn Margeirsson, Sigurjón Arason

Supported by:

RPC Tempra

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Styrene migration from expanded polystyrene boxes into fresh cod and redfish at chilled and superchilled temperatures

The aim of the experiment was to investigate the possible flow of styrene from foam plastic boxes to fresh cod and redfish fillets, which are stored at typical temperatures during sea transport of fresh fillets from Iceland to Europe or America. US buyers want fish fillets to be packed in plastic bags before packing in a foam box due to possible styrene contamination from foam to fish. Therefore, in this project, styrene was measured in fish, which had been stored without plastic bags in foam boxes, and the amount of styrene was compared with the standards of the US Food and Drug Administration (FDA). A total of 12 foam boxes containing cod or redfish fillets were stored for 4, 7 or 13 days at either -1 ° C or 2 ° C, which corresponds to the optimal and highest probable temperature in fresh fillet shipping. One 10-50 g sample was taken from the lower part of the bottom fish fillet in each box and had thus been in direct contact with foam plastic and therefore placed in a glass bottle. Subsequently, the 12 samples were sent for analysis to Eurofins, an international laboratory in Germany. The results show that the amount of styrene, as well as other undesirable substances such as benzene and toluene, was below 0.01 mg / kg fish in all twelve fish samples. The FDA guideline (maximum) is 90 mg of styrene per kg of fish per person per day, which is equivalent to The result of this experiment is that a consumer has to consume 9000 kg of fish daily to meet the FDA standard, which is a very unrealistic amount. The main conclusion of this experiment is that it is not necessary to pack fresh fish fillets in plastic bags for packing in foam boxes, which are stored and transported in refrigerated and supercooled conditions.

The aim of the study was to investigate possible styrene migration from expanded polystyrene into fresh cod and redfish, two important export fish species in Iceland, while stored under conditions mimicking transport by ship from Iceland to America and Europe. American buyers wish to have a plastic bag between EPS boxes and fish during transport as a safety measure due to possible styrene migration. Thus, this project was conducted to investigate if adding a plastic bag is necessary with regards to safety limits for styrene migration from packaging to food set by the FDA (US Food and Drug Administration). A total of twelve samples of cod and redfish were stored in EPS boxes manufactured by Tempra ltd. for 4, 7 and 13 days at two temperatures (-1 ° C, 2 ° C) which represent optimal and expected maximum storage temperatures during sea transport of fresh fish. A sample of 10-50 grams of fish, which had been in direct contact with the packaging, was taken from the bottom of each box, as it is considered the most hazardous place regarding styrene migration, and put in a glass bottle before analysis. Finally, the twelve samples of fish were sent to Eurofins, an international laboratory in Germany, for analysis. The results show that styrene content, and other solvent residues like benzene or toluene, were below 0.01 mg / kg in all twelve samples of fish. The FDA's daily intake limit of styrene is 90 mg / kg per person per day, which means that in this study an unrealistic intake of at least 9000 kg of fish would be necessary to exceed this FDA´s limit. The main conclusion from this study is therefore that a plastic bag is not needed to safely pack cod and redfish fillets into EPS boxes to be stored under chilled and superchilled temperatures.

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Reports

Changes in visual and textural quality in the redfish species (Sebastes marinus) during different storage regimes / Attempts against spot formation in fresh redfish fillets

Published:

01/11/2014

Authors:

Heather Philp, Ragnheiður Sveinþórsdóttir, Anna Hjaltadóttir

Supported by:

AVS (V 11 019-11)

Changes in visual and textural quality in the redfish species (Sebastes marinus) during different storage regimes / Attempts against spot formation in fresh redfish fillets

The fish species Sebastes marinus or redfish as it is called in everyday speech was the subject of this project where the goal was to find the cause and solve the problem of spotting fresh redfish fillets. These spots that form on fresh redfish fillets are yellowish and form within five days of processing the fillets, which creates problems due to their transport time and reduces their quality due to visual effects. The research carried out in the project covers the five days that the spot takes to form. In experiments to prevent the formation of stains, fresh redfish fillets were packed in a foam box where a mat on the bottom released carbon dioxide during the simulated transport and on the other hand the fillets were packed one by one in vacuum-packed containers. was also a mat under which emitted carbon dioxide. The results were that this packaging of the fillets prevented the oxidation of lipids in the flesh, but both the visual effect and the texture of the fillets deteriorated. Another experiment was performed where a redfish was bled as soon as it was taken on board the fishing vessel and compared with a redfish that came ashore unbleached (as usual) over a five-day period. The results were that the spots were less noticeable in the fish that had been bled on board the fishing vessel. The end result was that the probable cause of these yellowish spots that form on fresh redfish fillets is related to the breakdown of pigments that contain iron such as hemoglobin and myoglobin.

The species Sebastes marinus, commonly known as redfish, is the subject of a series of experiments aimed at determining the cause and mitigation of the appearance of yellowish stains on the surface of processed fillets. These detract from the visual quality and occur within five days of processing, thus precluding their transport to customer by sea and reducing their potential value. An investigation of progression described the appearance of the staining over a five day period. An attempt to prevent the staining was carried out by packing the fillets in two forms of modified atmosphere, one where the fillets were maintained in standard boxes with the addition of carbon dioxide releasing pads, and one where the fillets were individually sealed in vacuum bags with carbon dioxide releasing pads. It was found that the packaging prevented oxidation of lipids in the muscle but the visual and textural quality was greatly reduced. A further investigation monitored the appearance of stains in fish that had previously been bled at sea. It was found that the yellowish stains were less apparent in the bled fish compared to those that had not been bled. In addition, the textural quality was again reduced suggesting this may be a most suitable method for improving the quality such that the fresh fillets may be transported by sea. It is proposed that the likely cause is related to the breakdown of ironcontaining pigments such as haemoglobin and myoglobin.

Report closed until 01.12.2016

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