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

Process control for fishing, processing and processing of salted fish. Effect of cooling after fishing on the muscular structure of cod

Published:

01/08/2007

Authors:

Valur N. Gunnlaugsson, Jónína Ragnarsdóttir, Þóra Valsdóttir, Kristín Anna Þórarinsdóttir

Supported by:

AVS, Rannís Technology Development Fund

Contact

Valur Norðri Gunnlaugsson

Research Group Leader

valur.n.gunnlaugsson@matis.is

Process control for fishing, processing and processing of salted fish. Effect of cooling after fishing on the muscular structure of cod

This report describes the results of a cod image analysis. The effect of cooling methods after fishing on the muscular cod stock was assessed. It was not possible to detect differences in fillets depending on whether the fish had been stored in liquid ice or flake ice in a train or had been cooled separately on deck. Muscle changes during salt fish processing were monitored and the effect of injection was assessed. During salting, cells contracted and the extracellular space increased. There was a clear difference in the fillets depending on whether they were injected or not. During dehydration, the difference due to injection decreased again.

Results from image analyzes on cod are discussed in this report. The effects of chilling methods after catch on microstructure of cod fillets were also evaluated. No significant effects were observed, neither when extra chilling was added on deck nor with regard to different ice types (liquid ice / flake) used for storage of the fish. Changes in the fish muscle during heavy salting were examined and the effects of injection as the initial step in the process studied. During salting muscle cells shrank and the ratio of extracellular fluid increased. Significant effects of injection were observed after salting but during rehydration the difference decreased again.

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Reports

Process control for fishing, processing and processing of salted fish. Impact of post-catch cooling on utilization and quality (2)

Published:

01/07/2007

Authors:

Þóra Valsdóttir, Karl Rúnar Róbertsson, Egil Þorbergsson, 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 post-catch cooling on utilization and quality (2)

The purpose of the experiment was to investigate the effect of different cooling methods on board a fishing vessel on the quality and utilization of salted fish in terms of whether the fish was filleted or flattened before processing. There has been different experience with the use of liquid ice, but there have been theories that it has a negative effect on quality and utilization. The use of liquid ice in the train was at least worse in terms of quality and utilization compared to flake ice, whether it was processed fillets or flat fish. Discharge was more pronounced in fillets than in flat fish, but it could not be linked to cooling methods on board.

The aim of the trial was to investigate the effects of different cooling methods onboard a fishing vessel on curing characteristics during heavy salting of cod. The fish was either splitted or filleted before salting. It has been claimed the use of liquid ice for cooling of raw material, may lead to lower yield and quality of the products. The results showed that products from fish stored in liquid ice from catch to processing were similar or better than from fish stored in flake ice. Gaping appeared to be more related to fillets than splitted fish, but this factor could not be linked to chilling methods used onboard.

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