title: Trans isomers of EPA and DHA in omega-3 products on the European market.
abstract: The levels of trans isomers of eicosapentaenoic (EPA) acid and docosahexaenoic acid (DHA) in 77 omega-3 products on the European market have been studied. Fatty acids were analyzed as fatty acid methyl esters by gas chromatography with a flame ionization detector, using a cyanopropyl coated stationary phase. The amount of mono-trans EPA isomers relative to the corresponding all-cis isomer ranged from 0.19 to 4.5 %. The corresponding values for mono-trans DHA relative to the all-cis isomer ranged from 0.25 to 5.9 %. There was a strong correlation between the degree of isomerization of EPA and DHA, showing that DHA was 1.26 times more isomerized than EPA. Division of the samples into different product groups showed that samples with a low degree of isomerization were found in all groups, except one. This shows that a high degree of isomerization is avoidable, and also points to deodorization of the oils as the main source of trans isomers.
authors.affiliation: Department of Chemistry, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway.
authors.forename: Caterina
authors.initials: C
authors.lastname: Sciotto
authors.forename: Svein A
authors.initials: SA
authors.lastname: Mjøs
mesh_terms: D002849:Chromatography, Gas; D004281:Docosahexaenoic Acids / Q000032:analysis* / Q000737:chemistry*; D015118:Eicosapentaenoic Acid / Q000032:analysis* / Q000737:chemistry*; D005060:Europe; D015525:Fatty Acids, Omega-3 / Q000032:analysis* / Q000737:chemistry*; D005395:Fish Oils / Q000032:analysis / Q000737:chemistry; D005410:Flame Ionization
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid