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

Processing in small fishing vessels

Published:

01/03/2012

Authors:

Gunnar Þórðarson, Albert Högnason, Óðinn Gestsson

Supported by:

Technology Development Fund

contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Processing in small fishing vessels

Proper bleeding of catfish can have a significant impact on the quality of the products produced. It has been shown that there can be a big difference in the quality of well-drained fish and bad-blooded fish, and this effect can be observed after freezing of products. In this project, equipment was developed that could be used in small boats, but would ensure that all fish caught on the line receive the same treatment and sufficient time in heavy sea changes during bloodshed. A total of three trips were made with Gesti ÍS, a 10 ton liner made from Suðureyri and made by Fiskvinnsla Íslandssaga. In the last move, a new device, Rotex equipment from 3X Technology, was tested. The result is promising and the crew agreed that the equipment met all their requirements and the result clearly indicates that the quality of landed catch has improved. The ice scraper in the tanks in which the fish is stored until it is processed is clean and clear, but not mixed with blood and contaminated waste from the fish's stomach.

Proper bleeding of cod ‐ fish may have a significant impact on product quality. It has been shown that proper bleeding of fish can have a great difference on product quality, even after the products have been frozen. This project was to design equipments which could be used in small fishing vessels, and would ensure that all long ‐ line catch would receive equal handling regarding to bleeding processes. Three trips were made on Gestur IS, which is a 10 tons long ‐ line fishing vessel operated from Sudureyri and run by Icelandic Saga. The third and last of this test trips, a new equipment from 3X Technology, Rotex mechanism, was tested. The result looks promising and the crew agreed that the machine meets all their requirements and the result gives a clear indication of increased quality of the catch. The slush ice in the fish tubs are kept tide and clean, and devoid of blood water and other smutch from the bleeding operation, often contaminated by guts.

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Reports

Comparison of cooling techniques - Their efficiency during cooling their effect on microbial and chemical spoilage indicators

Published:

01/10/2010

Authors:

Lárus Þorvaldsson, Hélène L. Lauzon, Björn Margeirsson, Emilía Martinsdóttir, Sigurjón Arason

Supported by:

EU (contract FP6‐016333‐2) Chill ‐ on

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Comparison of cooling techniques - Their efficiency during cooling their effect on microbial and chemical spoilage indicators

The aim of the experiments was to investigate the effects of different types of ice during cooling and storage of whole, gutted fish on heat and damage processes. Three types of ice were used: traditional crushed plate ice ("flake ice") (referred to as PI here) as well as two types of ice scrapers (liquid ice) produced in specially designed ice scrapers (referred to as LIA and LIB here) with different salt and ice ratios. The results of temperature measurements showed much faster cooling with an ice scraper than conventional flake ice. Then cooling down proved to be somewhat faster with one type of ice scraper (LIB) than the other (LIA) because the temperature of haddock cooled in LIB went from 7.5 ° C down to 0 ° C in 20 - 30 min compared to about 55 - 60 min in LIA. The corresponding time for traditional flake ice was about 260 min. The difference in cooling time in the LIA and LIB can be partly explained by the 10% heavier fish in the LIA group. Cooling whole haddock from 10 ° C and 20 ° C gave similar results as cooling it from 7.5 ° C. Cooling time from 10 ° C to 4 ° C was 24 min for the LIB group and 36 min for the LIA group. The comparable cooling time from 20 ° C to 4 ° C was 46 min for LIB compared to 55 min for LIA. The results of microbiological measurements by cultivable methods showed that little growth of specialized pests (SSÖ) on haddock skin occurred early in the storage period, regardless of the cooling method. With further storage, microbial growth was similar between the cooling groups with an ice layer at the top of the vessel. Comparable microbial growth was observed in the flesh until on day 8, a significantly higher number of Photobacterium phosphoreum and H2S-producing bacteria were found in LIB-chilled fish. It is interesting to note that the different temperature profiles measured among the refrigeration groups did not reflect the microbial growth that took place. In fact, SSÖ's damage capacity did not appear to be less in the coldest conditions during the storage period, as significantly higher levels of TVB-N and TMA were measured in fish treated with ice scraping compared to conventional ice storage. It is possible that the conditions created by these waterlogged and salted conditions when using ice scrapers are undesirable and lead to a faster damage process than occurs under icy conditions.

The aim of study was to investigate the effects of different ice media during cooling and storage of whole, gutted whitefish on temperature control and spoilage indicators. The thermodynamic, microbial and chemical properties of whole, gutted haddock were examined with respect to the cooling medium in which it was stored. Three basic types of cooling medium were used: traditional crushed plate ice (PI + PI) and two types of commercially available liquid (slurry) ice, here denoted as LIA and LIB. The ice types were furthermore divided into five groups with different salinity and ice concentration. Microbiological analysis by cultivation methods revealed that growth of some specific spoilage organisms (SSO) on fish skin was delayed at early storage, independently of the cooling methods. With further storage, little or no difference in counts was seen among traditionally iced fish and those cooled in liquid ice for 2 h before draining and top layer icing. Even less difference was observed in the flesh microbiota developing until significant growth increase in Photobacterium phosphoreum and H2S ‐ producing bacteria was seen on day 8 in LIB cooled fish. Interestingly the differences obtained in the temperature profiles of fish cooled differently were not supported by different bacterial growth behavior. In fact, SSO spoilage potential was not reduced in the coolest treatments as time progressed, as demonstrated on day 8 by the significantly higher TVB ‐ N and TMA content of fish cooled in liquid ice compared to traditional icing. Conditions created by liquid ice environment (salt uptake of flesh) may have been unfavorable, causing an even faster fish deterioration process with increasing storage time compared to traditional ice storage. Evaluation of the thermodynamic properties showed that LIB gave slightly faster cooling than LIA. For haddock stored in LIB the flesh reached 0 ° C in 20‐30 min, but it took 57 min in LIA and around 260 min in crushed plate ice (PI). The difference in the cooling rate of LIA and LIB might, apart from the physical properties of the ice, be partially explained by the fish weight, being on average 10% more in the LIA group. The additional cooling rate experiments where whole, gutted haddock was cooled down from 20 ° C and 10 ° C gave similar results. When cooled down from 20 ° C the haddock reached 4 ° C in 46 min when chilled in LIB while the same process in LIA required 55 min. Similar difference was seen when the material was cooled down from 10 ° C, where fish chilled in LIB reached 4 ° C in 24 min and fish chilled in LIA reached 4 ° C in 36 min.

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