Plant Edible Oils - Detection of Disease-Causing Compounds due to Repeated Heating of Oils

The repetitive frying of food items in the same plant edible oil in order to reduce the cost is a common practice among street food vendors. However, repeated heating and frying can cause spoilage of oil by altering the physicochemical and nutritional qualities of cooking oils. The fried food items in the reused and reheated cooking oil lead to various diseases such as cancer, cardiovascular diseases, diabetes, atherosclerosis, etc. The health risks associated with using reused and reheated cooking oil are causing a significant concern in the medical world. The focus of this study was to identify the structurally modified fatty acids and formation of various toxic compounds in the reused and reheated cooking oil samples derived from plant-based and animal-based fast food items for comparative analysis. Fatty acid methyl esters (FAMEs) were analyzed by gas chromatography-mass spectrometry (GC-MS). The major toxic compounds detected from plant-based oil samples were phorbol (2.06%) and campesterol (50.06%). On the other hand, from animal-based oil, hentriacontane (50.8%), trimethylsilyloxytetradecane (70.2%), and estra-1,3,5 (10)-trien-17-β-ol (12.40%) were detected. Also, the amino acid profiling of the oil samples was performed using HPLC. Higher concentrations of the amino acids found were lysine (4.30μg/mL in plant-based oil samples and 5.24μg/mL in animal-based oil samples), phenylalanine (3.03μg/mL in plant-based oil samples and 40.6μg/mL in animal-based oil samples) and aspartic acid (9μg/mL in plant-based oil samples and 10.6μg/mL in animal-based oil samples). The outcome of this study infers that continuous consumption of food items deeply fried and heated with re-used oils would indirectly lead to complications in humans, and this comparative study reflects the distinction between the types of diets, animal-based and plant-based, and also between unused oil stock and repeatedly used cooking oil stock.