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Novel, Rapid Identification, and Quantification of Adulterants in Extra Virgin Olive Oil Using Near-Infrared Spectroscopy and Chemometrics


A new, rapid Fourier transform near infrared (FT-NIR) spectroscopic procedure is described to screen for the authenticity of extra virgin olive oils (EVOO) and to determine the kind and amount of an adulterant in EVOO. To screen EVOO, a partial least squares (PLS1) calibration model was developed to estimate a newly created FT-NIR index based mainly on the relative intensities of two unique carbonyl overtone absorptions in the FT-NIR spectra of EVOO and other mixtures attributed to volatile (5280 cm−1) and non-volatile (5180 cm−1) components. Spectra were also used to predict the fatty acid (FA) composition of EVOO or samples spiked with an adulterant using previously developed PLS1 calibration models. Some adulterated mixtures could be identified provided the FA profile was sufficiently different from those of EVOO. To identify the type and determine the quantity of an adulterant, gravimetric mixtures were prepared by spiking EVOO with different concentrations of each adulterant. Based on FT-NIR spectra, four PLS1 calibration models were developed for four specific groups of adulterants, each with a characteristic FA composition. Using these different PLS1 calibration models for prediction, plots of predicted vs. gravimetric concentrations of an adulterant in EVOO yielded linear regression functions with four unique sets of slopes, one for each group of adulterants. Four corresponding slope rules were defined that allowed for the determination of the nature and concentration of an adulterant in EVOO products by applying these four calibration models. The standard addition technique was used for confirmation.

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Fourier transform near infrared


Extra virgin olive oil


Fatty acid


Gas chromatography




Mass spectrometry


Partial least squares


Oleic acid


Linoleic acid


Palm olein


Refined olive oil


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The authors wish to thank Mary Bolton, California Olive Ranch, for providing EVOO samples.

Conflict of interest

The authors declared no conflict of interest.

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Correspondence to Hormoz Azizian or Magdi M. Mossoba.

Additional information

Dr. John K. G. Kramer has retired from Guelph Food research center, Agriculture and Agri-Food Canada.

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Azizian, H., Mossoba, M.M., Fardin-Kia, A.R. et al. Novel, Rapid Identification, and Quantification of Adulterants in Extra Virgin Olive Oil Using Near-Infrared Spectroscopy and Chemometrics. Lipids 50, 705–718 (2015).

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  • FT-NIR
  • PLS
  • Extra virgin olive oil
  • FA markers
  • Volatile compounds