Raman Spectroscopy–Based Characterization of Canola Oil

Abstract

In this article, Raman spectroscopy has been utilized for the first time to characterize pure canola oil samples extracted directly from its seeds through cold press and chemical method and six commercial oil brands. Raman spectra were acquired directly from oil samples by using laser at 785 nm to investigate their valuable ingredients. It has been observed that Raman bands evolving at 1156 and 1525 cm−1 represent beta-carotene, which are present in pure canola oil samples and absolutely absent in commercial brands. Furthermore, the effect of temperature on the molecular composition of pure and commercial oil brands has been investigated by heating individual samples at the temperatures of 100, 110, 120, 130, 150, 160, 170, 180, and 200 °C, each for 30 min. It has been found that pure canola oil retains beta-carotene and other valuable fatty acids until heated up to 150 °C; however, it showed a trend of thermal oxidation at all temperatures, whereas, in commercial brands, heating does not induce much spectral variations, which might be due to already treated with high temperatures during refining processes. Statistical analysis has been performed through principal component analysis (PCA) to produce classification among oil samples based on their minute spectral variations.