Detection of coconut oil adulteration with palm oil through NMR spectroscopic method

Abstract

Coconut oil is a costly commodity in the food and traditional medicinal sectors and its adulteration with cheap palm oil is a serious issue. The present study evaluates the application of 1H NMR spectroscopy to authenticate coconut oil, and to monitor its adulteration with the cheap palm oil substitute. Various parameters such as average chain length (14.25), saponification index (244.66 mg KOH/100 g), molecular weight (652.12), iodine value (8.27 mg/100 g), peroxide value (0.02 meqO2/kg) and percentage of unsaturation (7.81%) were calculated through the NMR technique, and were found to be in concurrence with the values obtained from wet lab experiments. The extent of palm oil adulteration can be detected through NMR by evaluating the chemical shift values for olefinic protons. The findings have a significant impact on both the food and traditional medicine sectors, as NMR spectroscopy can replace the conventional wet lab methods as a reliable and precise method for analysis.