Erucic acid evaluation in rapeseed and canola oil by Fourier transform-infrared spectroscopy


Correspondence: Dr. Syed Tufail Hussain Sherazi, National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan


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A simple and rapid method was developed for the determination of erucic acid in rapeseed oil by single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy. The various ratios prepared from the three different types of oils (rapeseed, canola, and sunflower) were run on gas chromatograph to identify amount of erucic acid. Therefore, a wide range of erucic acid (0.5–53.0%) was obtained for the calibration. The partial least squares (PLS) calibration was used for predicting erucic acid using spectral region at 2983–657/cm. The root mean square error of prediction (RMSEP), root mean square error of calibration (RMSEC), and root mean square error of cross-validation (RMSECV) were also determined to assess the accuracy of the method. The regression coefficient (R2) was obtained 0.999 with least errors of RMSEC (0.12%), RMSECV (1.96%), and RMSEP (1.38%). The accuracy of the FTIR method was evaluated by analyzing canola and rapeseed oil samples by GC-MS and the results of both the techniques were found to be comparable.

Practical applications: Generally, GC is used for determination of erucic acid in vegetable oils. But it needs the very laborious process of derivatization of fatty acids into their respective volatile methyl esters. Furthermore, lot of health hazardous chemicals and reagents are involved in the process of derivatization which are potential source for environmental pollution. Generally, FTIR spectroscopy has been recognized as a very simple, rapid, and cost effective technique. During the last decade, several researchers have used multivariate regression to build up calibration models based on FTIR data. The use of multivariate calibration methods is able to provide, estimates of the precision of the analysis, and yields important qualitative, quantitative, and analytical information. The objective of the present study was to develop a simple methodology for the quantitative analysis of low and high levels of erucic acid in canola and rapeseed oil, respectively by SB-ATR FTIR spectroscopy with PLSs regression.