Vol. 3, Issue 5 (2016)
Influence of frozen storage of fish on changes in lipids and fatty acids
Author(s): Mahdiye fadaii rayeni
Abstract: The freezing point of food is a critical factor for the determination of many physical properties such as freezing time (Planck’s equation), water activity, water distribution, amount of frozen water and thawing time. In fish muscle the freezing point is depressed below that of pure water because of small solutes present in the muscle water. The formation of ice crystals is proceeded by nucleation, which can be homo- or heterogeneous. Supercooling is the driving force for ice nucleation and is defined as the difference between the actual temperature and that of the solid-liquid equilibrium. Changes in lipids during frozen storage of fish can, directly or indirectly, lead to quality deterioration. Fish and other seafood have a high content of PUFA, which are very susceptible to oxidation during frozen storage, and lipid oxidation is the main reason for quality deterioration in frozen stored fatty fish. Furthermore whole lipids, free fatty acids (FFA) and oxidised lipids or their products can interact with proteins, in some cases resulting in quality deterioration of especially lean species.