Thermal degradation of volatile organic compounds in edible oils: A comprehensive HPLC analysis across varieties and heating durations

This study investigates the dynamic changes in the concentrations of various volatile organic compounds (VOCs) in edible oils subjected to prolonged heating. Using High-Performance Liquid Chromatography (HPLC) with a UV detector at 254 nm, we measured the concentrations of α-methyl styrene, β-methyl styrene, ortho xylene, meta xylene, para xylene, benzene, toluene, ethyl benzene, propyl benzene, isopropyl benzene, and iso-butyl benzene in coconut, cottonseed, groundnut, mustard, palm, rice bran, sesame, sunflower, rapeseed, safflower, and soybean oils over heating durations of 0, 2, 4, and 6 hours. The results provide a detailed illustration of the behaviour of these compounds under heat: Mustard oil initially had high concentrations of α-methyl styrene (103.00 µg/Kg) and β-methyl styrene (110.00 µg/Kg) which decreased to 46.00 µg/Kg and 52.00 µg/Kg. Cottonseed oil started with high benzene levels (48.00 µg/Kg) which were significantly reduced to 3.00 µg/Kg. Rice bran oil displayed an initial benzene concentration of 10.00 µg/Kg that reduced to 2.10 µg/Kg. Coconut oil, starting at 36.00 µg/Kg of benzene, saw a reduction to 3.00 µg/Kg. Palm oil began at 21.00 µg/Kg of benzene and decreased markedly to 0.02 µg/Kg. The reduction rates varied, indicating that different oil types have distinct thermal stability and volatile emission behaviours under similar heating conditions. This comprehensive dataset underlines important implications for food safety, especially concerning the selection and use of cooking oils in environments where prolonged heating is common, affecting both culinary quality and occupational health safety.