Reducing polycyclic aromatic hydrocarbons (PAHs) in olive pomace oil using short-path molecular distillation

Abstract

Bleached olive pomace oil (BOPO) was distilled using a short-path molecular distillation unit to determine the impacts of distillation conditions on the removal of 15 PAHs from the list of 16 EPA-priority pollutant PAHs. The removal of PAHs was achieved at elevated temperatures (110-230 degrees C) and pressures (0.05, 0.5, 5 mbar). The oil was also deodorised at 230 degrees C under 0.5, 1 and 5 mbar pressures to determine the effect of pressure during deodorisation on the removal of PAHs. High-performance liquid chromatography (HPLC) with fluorescence detector (HPLC-FLD) was used for quantifying PAH concentrations in oil samples. PAH concentrations in BOPO were considerably reduced after molecular distillation and both temperature increment and pressure decrease were effective for the removal of PAHs from olive pomace oil. When above 190 degrees C, BaP could be reduced to <2 mu g/kg at all pressures. Distillation at 230 degrees C under 0.05 mbar absolute pressure reduced the sum of four PAHs (BaP, Chr, BaA, BbF) to 7 mu g/kg, which meets the acceptable levels established by the European Union (10 mu g/kg). Deodorisation effectiveness was increased by decreasing absolute pressure, particularly for light PAHs.