Feasibility study of detecting palm oil adulteration with recycled cooking oil using a handheld NIR spectroscopy

Adulterated foods are causing health-related issues since there is no rapid method available for the detection of food fraud. The main objective of this study is to determine the feasibility of using near-infrared (NIR) spectroscopy in differentiating pure palm oil from palm oil adulterated with recycled cooking oil in varying concentrations. The deep-frying process was carried out for chicken nuggets and French fries as fried items using palm oil as a frying medium to produce used frying oil. The refining and bleaching process was applied to used frying oil to generate recycled cooking oil. Adulterated samples were developed with different concentrations of recycled cooking oil in pure palm oil (1%, 2%, 3%, 5%, 10%, 15%, 20%, 30%, 40% and 50%). Principal component analysis was applied to analyze the distribution of pure and adulterated palm oil samples. The classification accuracy of the proposed method using handheld NIR spectroscopy in distinguishing adulterated samples of lower concentrations was found to be low (below 50%). Adulterated palm oil samples of recycled cooking oil (RCO) concentration (15% and above) were found to show classification accuracy of 100% when detected through handheld NIR spectroscopy.