Reports

Superchilled Round Fish - Final Report / Supercilled Whole Fish - Final Report

Published:

01/03/2013

Authors:

Björn Margeirsson, Valur Oddgeir Bjarnason, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund (R 11 062‐11)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Superchilled Round Fish - Final Report / Supercilled Whole Fish - Final Report

The main objective of the project "Super-chilled whole fish - for death solidification", which began in July 2011, was to investigate whether super-cooling of whole fish on board a fishing vessel could extend the shelf life and increase the quality of the products. Appropriate temperature and time settings for red and touch refrigerators were sought with four refrigeration experiments and the best settings were used to supercool whole fish in a shelf life experiment. The results of a shelf life test indicate that supercooled processing of whole cod can extend its shelf life by two days. According to sensory evaluation, however, there was little difference in the shelf life of different fillet groups. Shelf life was estimated at 16-18 days, which is quite a long time for cod fillets. However, the freshness period of the experimental group with super-chilled fillets of super-chilled whole fish seemed to be somewhat longer than the other groups. As with whole cod, there was little difference between the fillet groups in terms of microbial growth, chemical and physical properties. Limited differences between experimental groups can possibly be explained by stable and supercooled storage conditions. With this in mind, it is recommended to carry out another similar experiment, simulating more typical environmental temperature processes in the transport of fresh fish products (0–4 ° C) than in this experiment (–1.4 to –1.2 ° C). The results of computerized thermodynamics and hydrology modeling indicate that such models could be used for the continuous design of red and touch chillers for whole fish.

The main aim of the R&D project "Superchilled round fish - pre ‐ rigor", which was initiated in July 2011, was to investigate whether superchilled processing of whole fish on ‐ board fishing ships could increase product quality and prolong storage life. The appropriate temperature and time settings for the superchilling equipment were studied in four cooling trials and the best settings applied when preparing samples for a storage life study. The results from the storage life study indicate that superchilled processing of whole cod can extend storage life by two days. However, differences in sensory scores between the fillet groups were small. Storage life was estimated between 16 and 18 days which is quite long storage life for cod fillets. However, the group with superchilled fillets from superchilled whole fish seemed to retain freshness a little longer than other groups. As in case of the whole cod, the differences in bacterial count, chemical and physical properties between the fillet groups were small. Very similar fish temperatures between both the whole fish and the fillet groups resulting from the superchilled storage conditions applied may be the main reason for the small differences obtained. Thus, another study with more common temperature conditions during transport and storage of fresh fish (chilled but not superchilled) should be performed. The results obtained in this study show that CFD modeling of fluid flow and heat transfer is a realistic and functional tool to simulate superchilling of whole fish in a CBC ‐ cooler. In future work CFD modeling can be used to determine optimal values for parameters such as holding time, chilling temperature and air velocity. 

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