Compositional information useful for authentication of krill oil and the detection of adulterants

Abstract Nuclear magnetic resonance (NMR) spectroscopy
and chromatography, particularly thin layer chromatography
with flame ionisation detector (TLC-FID), were used to investigate
fish oil adulteration of krill oil with ethyl esters and
triacylglycerol. Natural krill oil has higher levels of
eicosapentaenoic acid (EPA) and docosahexaenoic acid
(DHA) in phospholipid than in triacylglycerol and so high
levels of these omega-3 fatty acids in krill oil triacylglycerol
was indicative of adulteration. Carbon (13C) NMR detected
adulteration of krill oil with 10% or more anchovy oil, while
TLC-FID detected levels as low as 1% adulteration with EPA
ethyl esters. However, positional distribution of EPA and
DHA, as determined using 13C NMR, was similar for both
fish oil and krill oil, indicating that positional distribution
cannot be used to show adulteration. Phosphorous (31P)
NMR spectroscopy can show adulteration with low cost
sources of phospholipid but was not useful for determining
adulteration of krill oil with fish oil.