New Method for the Discrimination of Adulterated Flaxseed Oil Using Dielectric Spectroscopy

To develop a new and rapid qualitative and quantitative analysis of flaxseed oil adulteration with different vegetable oils, we investigated the dielectric spectroscopy coupled with multivariate methodology in the frequency range between 10 and 3000 MHz. Linear discriminant analysis was used to distinguish flaxseed oil from other adulterants based on dielectric spectra, and the oil samples were easily grouped in different clusters. The partial least square model was developed for the quantification of the sample adulteration percentage independent from the adulterating oil, which showed a good prediction capability for the adulterant concentrations. The calibration provided a correlation coefficient (R-value) of 0.9961, and the blind sample validation indicated that the R-value of the validation and precision analyses was close to 1. Analysis was characterized as having good precision by slightly low relative standard deviation. Thus, dielectric spectroscopy could be effectively used to discriminate adulterated flaxseed oil from different types of oils at 2% levels.