Adulteration of Olive Oil with Hazelnut Oil: To Enable Detection of Hazelnut Oil in Virgin and Refined Olive Oils

Olive oil is produced mainly in the Mediterranean countries. The delicate flavour and the health benefits associated with olive oil along with the low level of purification and processing have produced a market where the oil commands a high price. As a result of this there is an opportunity for fraudulent substitution or admixing of olive oil with cheaper edible oils, and therefore a need for techniques that can identify and quantify the presence of other edible oils in olive oil.
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Current methods are based on analysis of the fatty acid composition of the oils, however some edible oils (eg hazelnut oil) can not be distinguished from olive oil using these methods due to their high oleic acid content.
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This study aims to investigate two alternative methods for detecting adulterant oil in olive oil using the steroidal hydrocarbon content of the samples. The first method involves producing an n-alkane pattern for the oils using gas chromatography with flame ionisation detection (GC-FID). This should produce unique patterns for the different types of edible oils. The second method will look at the sterene content using GC mass spectrometry. These two techniques in combination should be able to identify and quantify any adulterant oils in a sample of olive oil.