Fatty acids, volatile compounds and microbial quality preservation with an oregano nanoemulsion to extend the shelf life of hake (Merluccius hubbsi) burgers

Hake (Merluccius hubbsi) is the most important fish of Argentinean industry. The preservative effects of an oregano essential oil (EO) nanoemulsion (NE) on hake burgers (FB) during 15 days at 4 degrees C were studied. Fatty acids determined by gas chromatography coupled with mass spectrometry (CG-MS), volatile compounds determined by solid phase microextraction (SPME) coupled with CG-MS, total volatile basic nitrogen (TVBN), and microbial count was measured. ANOVA and DCG tests were performed. After 14 days, significant differences were detected among samples (P <= 0.05). FB with EO (EO-FB) and FB with NE containing EO (NEEO-FB) had the highest content of EPA (eicosapentaenoic acid) (191.82 and 198.42 g kg(-1)) and DHA (docosahexaenoic acid) (107.97 and 110.87 g kg(-1), respectively). Also, NEEO-FB had the lowest microbial count (7 log CFU g(-1)). The incorporation of the oregano essential oil into a nanoemulsion improves the preserving activity in hake fish burgers.