Identification of Adulterated Cooking Oil by Raman Spectroscopy

A better quality of life comes with a healthy diet without adulteration or contamination. As much as the demand for purity in diet increases, the risk of adulteration also increases in daily edibles. The present study proposed Raman spectroscopy for the identification of used cooking oils to overcome adulteration. Unused cooking oil with different concentrations of used oil (waste oil) as an adulterant was examined by Raman spectroscopy along with principal component analysis (PCA). Increasing the concentration of used oil causes changes in Raman spectral features. The changes can be observed at 1413 cm⁻¹, 1521 cm⁻¹, and 1745 cm⁻¹ in Raman mean spectra of unused oil with the addition of different concentrations of the adulterant. Raman spectroscopy with PCA gives qualitative analysis and helps to monitor the quality of the cooking oil. PCA is a statistical tool that is used to examine variations in the given Raman spectral dataset. PC-1 shows more variability about 93.8% for the differentiation of the Raman spectral groups of the used and unused oil, while for unused oil and its different concentrations with adulterant, it shows a variability of 88.8%. These results demonstrate that Raman spectroscopy can be applied for the identification of adulterated oil. In the future, this spectroscopic technique can be used in the field of food chemistry because of its non-invasiveness and non-destructive analysis.