Marker method can help authenticate edible oils

Chinese researchers say they have developed a method for authenticating edible oils using a marker compound that is less resource-intensive than current methods.

The method – published in the journal Food Quality and Safety – has been tested in the analysis of virgin olive and camellia oils, which are known to be prone to adulteration with other, cheaper oils that can be hard to spot using traditional lab analysis.

The team, from Zhejiang University, zeroed in on beta-sitosterol, one of the fatty acids found in both oils, using gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionisation detector (GC/FID).

It found distinctive ranges between different types of oil for the biomarker, which has been linked to health benefits including anti-inflammatory, anti-ulcerative, and anti-tumour properties. The method was also applied to corn, peanut, walnut, soybean, canola and other vegetable oils.

Their authentication method eliminates the need for cumbersome processes like solid-phase extraction cartridges and thin-layer chromatography as well as derivatisation – needed to break down the oils into their constituent fatty acid parts – which avoids excessive manipulation of the samples.

The study showed a “unique fingerprint” for each oil which can be “leveraged as an instrumental marker in verifying the authenticity of these oils,” according to the scientists.

“The research undertaken by this team transcends merely addressing food fraud; it signifies a commitment to ensuring consumers reap the health advantages intrinsic to genuine [virgin camellia oil and virgin olive oil],” they add.

“As we chart the future, this study lays a robust groundwork for subsequent investigations and implementations within the food sector.”

Counterfeiting and fraud is a big problem for the $16bn-a-year olive oil industry, with some studies claiming that between 60 and 90 per cent of olive oils sold in the US are adulterated with cheaper pomace oil or oils from other plant species such as sunflower, canola and peanut.

In 2019, a Europol-coordinated operation resulted in the seizure of 150,000 litres of low-quality oils that had been adulterated with colourants to make them appear like extra virgin olive oils, with 20 arrest made.

Image by neufal54 from Pixabay