Discriminating Extra Virgin Olive Oils from Common Edible Oils: Comparable Performance of PLS-DA Models Trained on Low-Field and High-Field 1H NMR Data

Olive oil, the oil derived from the olive tree (Olea europaea L.), is used in cooking, cosmetics, and soap production. Due to its high value, some producers adulterate olive oil with cheaper edible oils or mislabel cheaper oils to increase profitability. These other edible oils can have chemical profiles similar to extra virgin olive oil but can cause allergies in sensitive individuals. Given these consequences, there is a need for methods to rapidly authenticate olive oils. Nuclear magnetic resonance (NMR) has been used for this purpose, as it requires minimal sample preparation and is non-destructive. By utilizing NMR spectra of the samples and machine learning models trained on known olive oil and edible oils, oil samples can be classified and authenticated. While high-field NMRs are commonly used due to their superior resolution and sensitivity, they are generally prohibitively expensive to purchase and operate, for routine screening purposes. Low-field benchtop NMR presents an affordable alternative. Here, we compared the predictive performance of partial least squares discrimination analysis (PLS-DA) models trained on low-field 60 MHz benchtop 1H NMR and high-field 400 MHz 1H NMR spectra. We demonstrated that PLS-DA models trained on low-field spectra perform comparably to those trained on high-field spectra.