Direct determination of polymerised triacylglycerides in deep-frying vegetable oil by near infrared spectroscopy using Partial Least Squares regression

► Determination of polymerised triacylglyceride (PTG) in deep-frying oils. ► Simple, fast and environmentally friendly method. ► Changes in the NIR region for quantitative determination of PTG by PLS regression. ► A global PLS model was established, providing a prediction error of 2.28% (w/w). ► Enables low cost on-site measurements with portable NIR spectrometers.