The effect of monthly changes on omega-3- fatty acids content of lipid components of Mackerel (Scomber japonicus)
Abstract
The present study carried out to determine monthly changes in omega-3- fatty acids content of total lipid, neutral lipids and phosopholipids of mackerel (Scomber japonicas) fish from Libyan coast in months of June, August, October and December of 2002. Edible parts of mackerel tissues were minced and used for lipid extraction by a mixture of chloroform: methanol (2:1). Extracted lipid were separated into neutral lipids and phospholipids by chromatographic column and which their components of fatty acids were identified using gas – liquid chromatography technique ( GLC). Total lipids, neutral lipids, phospholipids contents ranged between 1.18 – 9.87 % (g/100g meat), 58.60 – 91.24 % (g/100g lipid) and 10.39 – 42.39 % (g/100g lipid), respectively. Statistical analysis showed a significant differences at (p<0.01) between the total lipids, neutral lipids, phospholipids and 0mega-3-polyunsaturated fatty acids (ω-3 PUFAs) among the months of the study. The percentage of decosahexaneoic acid (DHA C22:6) was higher than the percentage of ecosapentaenoic acid (EPA C20:5), and it was dominant in ω-3 PUFAs group of all lipid classes. The highest content of both DHA and EPA of total lipids, neutral lipids and phospholipids was in month (June, August and December) and (June, December and December), respectively. Both of DHA and EPA were recorded the highest value in December 7.94 and 22.80% in phospholipids composition. Average total percentage of ω-3 PUFAs was higher in phospholipids composition 25.73%compared to ω-3 PUFAs in total lipids 20.03% and neutral lipids 24.59% composition. The study conclude that monthly variation have effect on omega 3 fatty acids contents of all lipid classes.
