Samantekt:
Lipid degradation of cod liver during frozen storage was studied, where the effects of storage temperatures (−18/−24°C), packaging methods (vacuum packing/regular plastic bag and waxed cardboard box), and seasonal variations (March/June/September) were evaluated. For this, the formations of free fatty acids (FFA) and peroxide value (PV) were analyzed. Lipid degradation within different parts of the liver (middle/surface) was also investigated. Increase in FFA and PV was observed for most of the samples throughout the frozen storage period. Vacuum packaging and lower storage temperature had a significantly stronger preservative effect on lipid degradation in all seasons. Higher FFA content was observed in cod liver captured in June than in its counterparts from September and March. More intense increase in PV was observed for liver collected in June compared to September. Furthermore, significant difference in PV was observed in different layers of the liver while FFA showed minimum variation between the surface and the middle part of the cod liver. Based on the present results, packaging method and storage temperature have a significant effect on lipid hydrolysis and oxidation in frozen cod liver.