Lipid changes and sensory quality of whole- and gutted rainbow trout during storage in ice
Acta Ichthyologica et Piscatoria
Background. The aquaculture rainbow trout may be a valuable source of long chain n-3 polyunsaturated fatty acid (LC n-3 PUFA). In the retail these fish are mainly present as a whole or gutted. The present study was aimed at comparing changes occurring in lipids of whole and gutted rainbow trout stored in ice. Materials and Methods. The analysis were performed after 0, 3, 7, and 14 days of storage in ice at 2°C and the following assays were carried out: proximate composition; lipid composition
... lipid composition high pressure liquid chromatography (HPLC); fatty acid composition gas chromatography /mass spectrometry (GC/MS) by direct tissue saponification; contents of lipids extracted, using the Bligh-Dyer technique; UV-VIS, IR, and fluorescence lipid spectra; peroxide value (PV); anisidine value (AsV); and acid value (AC). Results. Gutting prior to storage made it possible to extend the sensory shelf-life by about 2-3 days and affected the quantitative fatty acid composition and oxidation level during storage in ice. The rainbow trout lipids are resistant to oxidation; oxidation product decomposition rather than lipid oxidation proceeds during storage, the decomposition being more intensive in whole than in gutted fish. It is only when the fish lose their eating quality (2 weeks) that a small increase in the level of oxidation occurs, accompanied by an about 15% loss of n-3 PUFA and a 20% loss of DHA, but only in the whole fish. Conclusion. Gutting rainbow trout prior to storage in ice is appropriate by the extending the shelf-life by about 2-3 days and keeping stable amount of n-3 PUFA during 2 weeks of storage.