The effects of extracting procedures on occurrence of polycyclic aromatic hydrocarbons in edible oils.

Polycyclic aromatic hydrocarbons (PAHs) are one of the most hazardous naturally occurring chemical contaminants of food. Edible oils are easily contaminated by PAHs generated during high-temperature processing steps such as oil extraction and refining. In this study, the effects of different extraction methods on the levels of PAHs in sesame oils and red pepper seed oils were assessed. GC-MS was used to determine the levels of PAHs in edible oils. Sesame oils extracted from seeds by plate-pressing extraction method had lower levels of PAHs than those extracted by screw-expeller extraction method from sesame flour. Furthermore, the levels of PAHs increased by 62.2% when the extraction time was longer. Notably, the PAHs already present in oils could be effectively reduced by refining procedures such as sinking, centrifugation, filtration, and neutralization with alkali.