Determination of polar components in frying oils by Fourier-transform near-infrared spectroscopy.

A rapid and convenient method was developed to determine the polar components (PC) of frying oil by Fourier-transform near-infrared (FTNIR) spectroscopy. One hundred twenty six oil samples were used to PC determination by column chromatography and FTNIR spectroscopy combined with partial least-square (PLS) calibration. The optimal PLS calibration was obtained after the Savitzky-Golay smoothing and first derivative treatment performed in the wavelength ranges of 4963 cm(-1) to 4616 cm(-1), 5222 cm(-1) to 5037 cm(-1), and 5688 cm(-1) to 5499 cm(-1). The obtained correlation coefficient (R) was 0.998 and the root mean square error of calibration was 1.0%. The PLS calibration was validated, and the results showed that the highest correlation (R) was 0.997 between reference value and the FTNIR predicted value and the root mean square error of prediction was 1.3%. Therefore, the FTNIR technique can be effectively applied to quantify PC with the advantages of simple operation and no pollution.