Regiospecific Analyses of Triacylglycerols of Hoki (Macruronus novaezelandiae) and Greenshell™ Mussel (Perna canaliculus)

Abstract

AbstractThe lipid profiles of the two most important New Zealand marine oil sources were investigated, with particular attention to the regioisomeric compositions of triacylglycerides (TAG), using 13C‐nuclear magnetic resonance analysis. Oils from hoki (Macruronus novaezelandiae) and Greenshell™ mussel (Perna canaliculus) (GSM) were analyzed for their lipid content, lipid class and fatty acid profile. The regiospecific distribution of long chain (C ≥ 20) polyunsaturated fatty acids (LC‐PUFA) between the sn‐1,3 and sn‐2 glycerol positions was calculated from 13C responses in the carbonyl region in the triacylglycerol fraction. Rendered hoki oil (RHO) produced from the viscera and filleting discards, had a similar lipid profile to that of hoki liver oil (HLO) confirming that the liver is the major source of oil in RHO. The regioisomeric distribution of fatty acids showed differences between the two oil sources. Docosahexaenoic acid (DHA) had a regioisomeric distributional preference to the sn‐2 position in TAG from all the oils (59.2% HLO, 54.3% RHO and 63.4% GSM). Eicosapentaenoic acid (EPA) had a more even distribution along the triacylglycerol backbone in hoki TAG (29.1% HLO, 33.6% RHO) while there was a slight sn‐2 positional preference in the GSM TAG (37.6%). This regioisomeric information is vital to distinguish LC‐PUFA‐rich marine oils from other marine sources for authentication purposes.