Direct discrimination of palm oil as an adulterant in edible oils using a portable Raman spectrometer

The common adulteration process in oils involves mixing low-cost and high-cost edible oils. Palm oil has been widely used as an adulterant in the Indian market. In the present work, different ratios of palm oil were mixed with high-cost edible oils such as sunflower, groundnut, coconut, and gingelly. Raman peak intensity for all edible oils individually and after mixing palm oil as an adulterant was studied using a portable Raman spectrometer. The peaks at 838 cm-1, 868 cm-1, 973 cm-1, 1077 cm-1, 1262 cm-1,1300cm-1, 1438 cm-1, 1655 cm-1, and 1745 cm-1 represent vibration due to the (C-C) stretching, (CH) wagging from cis (-CH = CH-), delta(=CH), skeletal C-C stretching, (CH) deformation of (CH2), scissoring vibration of CH2 group, (C=C) stretching from cis -(CH=CH-), and (C=O) stretching vibration from (RC=OOR) for sunflower oil, groundnut oil, gingelly oil, and coconut oil. An attempt has been made to detect 12.5 mL of palm oil in 100 mL of high-cost edible oil. Raman peaks disappeared while adding more than 12.5 mL of adulterate oil. The disappearance of peaks in edible oils, 973 cm-1 for sunflower oil, 970 cm-1 for groundnut oil, 1122 cm-1 for coconut oil, and 1745 cm-1 for gingelly oil respectively. The obtained results will be used for futuristic data analysis to directly detect adulterants in the oils.

Automated summary

This study investigates the adulteration process of mixing palm oil with high-cost edible oils using Raman spectroscopy. By studying the Raman peak intensity of different edible oils, the presence of palm oil and other adulterants in oils can be detected directly.