Olive Oil Offenses: How NMR Is Used To Detect Adulteration of Olive Oil

Olive oil is used for a wide array of things in the modern kitchen from greasing pans to butter alternatives to dipping sauce for bread. It is a premium oil known for its flavour.  This kitchen necessity is known for its nutritional characteristics and attractive flavor.

But, as it turns out, not even olive oil is immune to crime. And we don't mean the high crimes of being too tasty.

Fraudulent adulteration of olive oil

Because of its cost, olive oil is especially susceptible to fraudulent adulteration. Many cases of adulteration are innocuous and involve someone trying to make more money by passing off cheap, inferior oils as authentic extra virgin olive oil. Other cases may be more lethal where someone with criminal intent contaminates olive oil with toxic chemicals, such as the Toxic Oil Syndrome seen in Spain in 1981. 

To fight back against fraudulent adulteration, the USDA and International Olive Council (IOC) have been doing their best to regulate olive oil production and distribution. But despite their efforts, adulteration continues to be a problem in the olive oil industry. Fortunately, benchtop NMR spectrometers can help detect the presence of foreign substances or cheaper, more abundant edible oils, such as soybean, in olive oil.

How is olive oil adulteration determined?

Gas or liquid chromatography-mass spectrometry are the typical methods used in determining whether olive oil has been altered. However, these methods cannot detect unanticipated substances and are time-consuming, requiring extensive data analysis and sample preparation.

NMR spectroscopy may not typically be used in the context of determining olive oil adulteration, but benchtop NMR spectrometers can be a handy tool. NMR spectrometers range from 60 MHz to 100 MHz, are non-destructive and non-targeting, offering useful information on the distinct chemical signatures in the proton NMR spectrum. Unlike the more typical methods used in detecting olive oil adulteration, benchtop NMR spectrometers offer fast and efficient data collection and analysis.

Each edible oil has a characteristic fatty acid profile. This is because oils are primarily composed of triglycerides with fatty acid chains. Extra virgin olive oil has fewer polyunsaturated fats than other types of oils, including soybean oils. Because extra virgin olive oil has fewer polyunsaturated fats, this oil will show up on NMR spectra with weaker bis-allylic resonance compared to oil that has been adulterated with soybean oil.

Benchtop NMR spectrometers can be used for a wide array of other needs in various different industries including food science. To learn more about benchtop spectrometers and NMR spectrometer applications, contact Nanalysis today.