Characterization of wax esters in the roe oil of amber fish,Seriola aureovittata

Abstract

AbstractThe wax esters of the roe oil of the amber fish,Seriola aureovittata, have been resolved by high‐performance liquid chromatography (HPLC) in the silver‐ion mode. Each of the fractions collected was transmethylated, and the fatty acids and alcohols were identified by gas chromatography/mass spectrometry (GC/MS) as the picolinyl esters and nicotinates, respectively. Their compositions were determined by GC. The fatty acid composition is complex, and the main components are C18:1n‐9 (35.5 mol%), C22:6n‐3 (20.3 mol%), and C16:1n‐7 (10.7 mol%), while fatty alcohols are limited to saturated (C16:0, 60.3 mol%; C18:0, 15.3 mol%; C14:0, 5.1 mol%) and monoenoic alcohols (C18:1n‐9, 6.5 mol%; C16:1n‐7, 4.5 mol%) with traces (<0.1 mol%) of polyunsaturated fatty alcohols such as C20:3n‐3, C20:4n‐6, C20:5n‐3, and C22:5n‐3. Silver‐ion HPLC exhibited excellent resolution in which fractions were resolved on the basis of the number and configuration of double bonds as well as the distribution pattern between the acid and alcohol moieties of the molecules with a given number of double bonds. The main wax ester fraction are those of monoenoic acid‐saturated alcohol species, hexaenoic acid/saturated alcohol species, and pentaenoic acid/saturated alcohol species. Appreciable specificity was observed in the esterification of fatty acids with alcohols, and surprisingly, no saturated acid‐monoenoic alcohol species were detected.