Concomitant oxidation of fatty acids other than DHA and EPA plays a role in the characteristic off-odor of fish oil

Abstract

The aim of the present research was to explore the development of off-odors in fish oil from the perspective of fatty acid oxidation. It was found that the off-odors elicited by the two major ω-3 PUFAs in fish oil, i.e. DHA and EPA, were different from those by fish oil. Results showed that simultaneous oxidation of fatty acids other than DHA and EPA can be involved. The off-odors of fish oil was successfully simulated by combining oxidized samples of DHA, EPA and sunflower oil. Therefore, oxidation of oleic and linoleic acids also contributed to the off-odors in fish oil. A novel analytical approach that consisted in the combination of gas chromatography-ion mobility spectrometry (GC-IMS) and orthogonal partial least squares discriminant analysis (OPLS-DA) was applied to identify differences in the volatile components between the recombinant oil and the fish oil.