Discrimination of vegetable oils using NMR spectroscopy and chemometrics

- 9 types of vegetable oil were analyzed by 1H and 13C NMR.
- The oil's composition was determined from the NMR data.
- The oils were discriminated according to the botanical origin using PCA.
- The discriminating chemical compounds were determined.
- A method for detecting low levels of olive oil in sunflower oil was described.

In this study, 44 samples, either pure or combined into binary blends of vegetable oils with different botanical and geographical origin have been analyzed. 1H and 13C NMR analysis was used to determine the saturated fatty acids, oleic acid, linoleic acid, linolenic acid and iodine value. Oil samples were separated according to the botanical origin using principal component analysis. Results found virgin olive oils clustered close together in spite of the different geographical origin while walnut oil varied greatly with country of origin. Blends of 1% olive oil in sun-flower oil were detected using specific 1H and 13C signals. The results strongly support the capability of NMR and chemometrics to be used in quality assessment of vegetable oils in terms of their botanical origin.