Reports

Instructions for the cooling ability of slurry ice intended for chilling of fish products in fish containers

Published:

01/06/2016

Authors:

Björn Margeirsson, Sigurjón Arason, Þorsteinn Ingi Víglundsson, Magnea G. Karlsdóttir

Supported by:

AVS Fisheries Research Fund (R 034‐14)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Instructions for the cooling ability of slurry ice intended for chilling of fish products in fish containers

Objectives of the project Optimization of fresh fish transport is to improve the handling of fresh fish products in container transport and thereby increase their shelf life and the possibility of further transport by sea from Iceland. In work step 1, the aim is to estimate the appropriate amount and type of ice scraper to maintain the fish temperature at -1 ° C during transport in tanks. Heat transfer models are made from 340 PE and 460 PE food pots from Sæplast to estimate the required amount of ice scraper to maintain -1 ° C inside the pots, which is the optimal temperature for storing fresh whitefish products. Pre-cooling of fish products before packing in pots has a decisive effect on the amount of products that can be placed in pots if it is required to maintain the fish temperature -1 ° C. This is explained by the fact that with increasing fish temperature during packing, an increased amount of ice scraper is needed to lower the fish temperature to -1 ° C, thereby reducing the space for the fish inside the tank. The volume utilization of the pot, i.e. quantity of fish products in a tank, it is of course necessary to maximize in order to minimize transport costs and make sea transport of fish products packed in ice scrapers in a tank a viable alternative to sea transport in foam boxes. These guidelines should be used to estimate the amount of fish products that can be packed in 340 PE and 460 PE Sæplast tanks. The aim is to pack the fish in an ice scraper with a temperature of -1 ° C, an ice ratio of 35% and a salinity ratio of 1.2% and the amount of ice scraper is sufficient to maintain -1 ° C in an ice scraper and fish for four days at ambient temperatures between -1 ° C and 5 ° C. It should be noted that the instructions only take into account the need for refrigeration and not a possible, undesirable color that can be created on the bottom fish layers in a tank and can potentially cause loss of utilization and quality.

The aim of the project Optimization of fresh fish transport is to improve handling of sea transported fresh fish products, thereby improving their quality and increasing the possibility of sea transport from Iceland. The aim of work package no. 1 is to estimate the suitable quantity and type of slurry ice in order to maintain the optimal fish temperature of –1 ° C during transport in fish containers (tubs). Heat transfer models of 340 PE and 460 PE fish containers manufactured by Saeplast are developed for this purpose. Precooling of fresh fish products before packing in slurry ice in containers has a dominating effect on the maximum fish quantity, which can be packed in each container assuming a maintained fish temperature of –1 ° C. This is because an increased fish packing temperature increases the required amount of slurry ice in order to lower the fish temperature down to –1 ° C, thereby decreasing the volume for fish within the container. The fish quantity within the container must certainly be maximized in order to minimize the transport cost and make sea transport of fresh fish products in slurry ice in containers a viable option. These guidelines should be useful to estimate the fish quantity, which can be packed in 340 PE and 460 PE Saeplast containers. The temperature, ice ratio and salinity of the slurry ice assumed are –1 ° C, 35% and 1.2%, respectively. Furthermore, it is assumed that the amount of slurry ice applied is sufficient to maintain the slurry ice and fish at –1 ° C for four days at ambient temperature between –1 ° C and 5 ° C.

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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

Effect of cooling and packaging methods on the quality deterioration of redfish fillets

Published:

01/09/2011

Authors:

Hélène L. Lauzon, Aðalheiður Ólafsdóttir, Magnea G. Karlsdóttir, Eyjólfur Reynisson, Björn Margeirsson, Sigurjón Arason, Emilía Martinsdóttir

Supported by:

EU IP Chill ‐ on (contract FP6‐016333‐2)

contact

Aðalheiður Ólafsdóttir

Sensory evaluation manager

adalheiduro@matis.is

Effect of cooling and packaging methods on the quality deterioration of redfish fillets

The aim of the experiment was to evaluate the effect of slush ice cooling after filleting and / or packing in vacuum packaging on the deterioration of the quality of fresh redfish fillets. The fillets were stored at -1 ° C for 6 days to simulate well-executed sea transport in foam plastic boxes and then at 2 ° C, as happens after delivery abroad and storage in retail. Product and ambient temperature were monitored from packaging and sensory evaluation, microbial and chemical measurements were performed. The fish was caught in the spring and processed 6 days after fishing. The results show that the quality of the raw material was not the best during packaging as the development process (PV and TBARS) was well underway. This probably explains why none of these refrigeration methods led to an increase in shelf life. It was also found that there was no benefit in cooling the fillets unprotected in slush ice as the microbial growth and formation of TVB-N and TMA in the fillets was faster with further storage. However, it seems preferable to refrigerate vacuum packed fillets in ice cream as this method has led to slower growth of pest microorganisms, lower TMA levels and a slower development process. Photobacterium phosphoreum is important in the process of damaging fresh redfish fillets, regardless of the packaging method.

The aim of this study was to evaluate the effect of slurry ice cooling in process (post ‐ filleting) and packaging method (+/‐ oxygen) on the quality deterioration of skinned redfish fillets during storage in expanded polystyrene boxes simulating well ‐ performed sea freight transportation (6 days at ‐1 ° C) followed by storage at the retailer (2 ° C). Also, to assess the use of vacuum ‐ packaging to protect the fillets from direct contact with the cooling medium (slurry ice) and to achieve superchilling following extended treatment. Temperature monitoring as well as sensory, chemical and microbial analyzes were performed. The fish was caught in the spring and processed 6 days post catch. The results show that quality of the fillets was not optimal at packaging, due to the detection of primary and secondary oxidation products. This may have been the reason why shelf life extension was not achieved by any of the methods evaluated. Further, there was no advantage of cooling the fillets unpacked since this method stimulated microbial growth and formation of basic amines. On the other hand, slurry ice cooling of vacuum ‐ packaged fillets led to a slower microbial development, the lowest TMA level and delayed autoxidation. Finally, the importance of Photobacterium phosphoreum in the spoilage process of redfish fillets, independently of the packaging method, was demonstrated.

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