Nondestructive determination of canola oil oxidation causes: A near-infrared spectroscopy coupled with liquid chromatography-mass spectrometry for analyzing triacylglycerol hydroperoxide isomers

Monitoring oxidation causes ( i.e. radical and/or photo-oxidation) of vegetable oil gives very important information for its quality control. This study aimed to develop a rapid and simple near infrared (NIR) spectroscopy method to explore the oxidation causes in vegetable oil by quantifying triacylglycerol hydroperoxide (TGOOH) positional isomers proceeded by different oxidation causes. First, the concentrations of TGOOH isomers were determined by liquid chromatography-mass spectrometry. Partial least square regression for concentrations of TGOOH isomers (R 2 : 0.994–0.998) using NIR spectra in the regions of 7500–6000 cm −1 and 5500–4500 cm −1 as explanatory variables. Principal component analysis revealed that those models were created because NIR spectra capture trace changes of the peak around 6980 cm −1 (-CH 2 -) and 5260 cm −1 (H 2 O) derived by different oxidation causes ( i.e. radical and/or photo-oxidation). The application of this method to various kinds of vegetable oil is expected to lead to a simple and rapid quality evaluation of vegetable oil. • A nondestructive NIR method to determine oxidation causes of canola oil was developed. • NIR captured trace changes of water content derived from different oxidation causes. • The present NIR method will be a powerful tool for evaluating vegetable oil quality.