Quantification and distribution of omega-3 fatty acids in South Pacific fish and shellfish species

Abstract

Fatty acid composition and distribution in edible species of fish and shellfish captured in the South Pacific were studied, with a focus on n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA). Fatty acids were quantified using gas-chromatography coupled with flame ionization detection (GC-FID), and the distribution of different fatty acids within lipid classes (neutral and polar lipids) was achieved after oil extraction using the Folch method and separation of lipid classes via solid-phase extraction for further GC-FID analysis. Red cusk-eel was the fish species with the lowest content of both EPA and DHA (40.8 and 74.4 mg/100 g, respectively) whereas mackerel contained the highest amount (414.7 and 956.0 mg/100 g for EPA and DHA, respectively). Sea squirt was the shellfish species with the highest content of EPA and DHA (375.0 and 165.7 mg/100 g, respectively) whereas the lowest amount of EPA + DHA was found in Chilean abalone (63.6 mg/100 g). PUFA were mostly found in neutral or polar lipids depending on the studied species. Indexes used to discuss the nutritional quality of lipids (PUFA/SFA, n-6/n-3 ratio and the hypocholesterolemic/hypercholesterolemic fatty acid index) were calculated and reported in the manuscript. This information provides a novel nutritional insight which may be useful to help nutritionists and other health professionals give more accurate counseling for the population to reach the recommended daily intakes of EPA and DHA.