Model systems for studying biochemical changes in fish muscle successfully developed

By: Karin Svensson & Annette Almgren


30 May 2005

Researchers at Chalmers University of Technology in Göteborg have developed a new, sensory based model system for testing factors giving rancid taste in fish.


One of the objectives in project 4.3 LIPIDTEXT is to establish experimental systems. These systems will give a better understanding of the mechanisms by which lipid oxidation products are formed in seafood and how the use of antioxidants can prevent the development of rancid taste. Whole fish muscle is very complex in its composition, which makes it difficult to evaluate the influence of different individual factors on e.g. lipid oxidation. One of the objectives within LIPIDTEXT is to develop a simple fish based model system where some answers can be given on what controls lipid oxidation in fish. Studies are carried out at Chalmers University of Technology in Sweden. By washing out endogenous water soluble substances from minced fish, purer systems are obtained but which still contain the necessary oxidation substrates.

Washed model systems from three distinct types of fish (cod, salmon and herring) have successfully been developed in this way. The systems have shown to be reliable and reproducible and their main characteristics, e.g. contents of neutral fat and carotenoids, are retained. One major advantage of these model systems is the possibility to reconstruct the whole fish muscle by adding back specific compounds in a controlled manner. By subjecting to pre-heating, the systems can also be used for simulating oxidation in ready-made fish products. The possibility to change chemical and physical conditions makes these model systems very flexible and useful. The group at Chalmers University of Technology has e.g. compared heme and low molecular metals as initiators of lipid oxidation. In the future we will also test various natural antioxidants in order to find substances that can be used for maintaining high sensory and nutritional quality of seafood products.


Development of “painty odor” as a measurement of hemoglobin-mediated lipid oxidation in model systems from cod, herring and salmon. Controls, without hemoglobin, are shown as dashed lines. Painty odor was determined by sensory analysis of the headspace above the samples. A small internal panel was used, and the sensory scale was from 0 to 100, with 100 representing the strongest intensity.