The Use of Fourier Transform Infrared Spectroscopy for Quantification of Adulteration in Virgin Walnut Oil

Abstract

Currently, the authentication of virgin walnut oil (VWO) has become very important due to the possible adulteration of VWO with cheaper plant oils such as soybean oil (SO), puer tea seed oil (PO), and sunflower oil (SFO). Methods involving Fourier transform infrared (FT-IR) spectroscopy combined with chemometric techniques (partial least square) were developed for quantification of SO, PO, and SFO in VWO. IR spectra of oil samples were recorded at frequency regions of 4000–650 cm−1on horizontal attenuated total reflectance (HATR) attachment of FT-IR. PLS model correlates the actual and FT-IR estimated values of oil adulterants (SO, PO, and SFO) with coefficients of determination (R2) of 0.9958, 0.9925, and 0.9952, respectively. The obtained RMSEC values of SO, PO, and SFO in VWO are 1.35%, 1.85%, and 1.43% (v/v), respectively. The method, therefore, has potential as a rapid method for quantification of product adulteration.

Application of Fourier Transform Infrared Spectroscopy for the Oxidation and Peroxide Value Evaluation in Virgin Walnut Oil

“…Due to the fact that the intensities of the bands in the spectrum are proportional to concentration (i.e., Beer's law is obeyed) and coupled with the chemometric techniques, FT-IR spectroscopy becomes an excellent tool for quantitative analysis. Several applications have been performed using this analytical approach together with chemometric methods, to detect walnut oil adulteration [6]; evaluate olive oil freshness [7]; monitor fatty acid composition of virgin olive oil [8]; and assess oil oxidation [9][10][11].…”

Fatty Acids analysis and Antioxidant activity of Fixed oil of Quercus Infectoria, Grown in Jordan

“…3). The signal at 800 cm -1 (=CH-out of plane bending) was not observed in different fixed oil obtained from soyabean, sunflower or virgin walnut oil seeds 27 .…”

Detection of lard contamination in five different edible oils by FT-IRspectroscopy using a partial least squares calibration model

“…The region at 1665 cm −1 gives information about the C=C link and is representative of polyunsaturated fatty acid in the molecule and is in ascending order as coconut, lard, olive, mustard, canola, and sunflower. The region at 1440-1445 cm −1 represents vibration of deformation (CH) and total unsaturation, which is greatest in olive and least in coconut [35].…”