Temporal Changes of Total Lipids in Salted Salmon Roes During Storage

Abstract

Salted salmon roes (“Sujiko” in Japanese) were stored at 5 °C for 4 weeks, -3°C for 8 weeks and -18°C for 16 weeks. Then, temporal changes of chemical properties, lipid composition and fatty acid composition of total lipids extracted from various samples were investigated. The results may be summarised as follows total lipids contents in salted salmon roes showed scarcely any changes. However temporal increases of acid value, peroxide value and carbonyl value of total lipids were observed at each storage temperature, while iodine value decreased during storage. Particularly, the above changes in case of storage at -18°C were the smallest in this study, In brief, storage at -18 °C was effective to control for lipid deterioration. Regarding the temporal changes of various lipid contents (g/100g samples) in total lipids, compound lipid fraction content decreased during storage at each temperature, while neutral lipid fraction content increased. Further-more, the temporal decreases of triacylglycerol (major lipid of neutral lipid fraction) content and phosphatidylcholine (major lipid of compound lipid fraction) content were observed during storage, while free fatty acid content clearly increased. The smallest changes were observed at -18°C storage. Regarding the temporal changes of major fatty acid composition of total lipids, neutral and compound lipid fractions, the decrease of highly unsaturated acid contents (wt%) such as 20 : 5, 22 : 6 acids and the increases of saturated acid contents such as 16 : 0, 18 : 0 acids were observed at each storage temperature. And the temporal changes of major fatty acid composition of compound lipid fraction were greater than those of other lipid fractions. Furthermore, these tendencies were the least conspicuous in case of storage at -18°C.