LAUSR

Changes in polycyclic (PAH) and oxygenated (OPAH) aromatic hydrocarbon concentrations in vegetable oils during storage for 270days at 25°C or 4°C were investigated. The concentrations of OPAHs and PAHs increased with storage time. The increase in PAH concentration was mainly caused by light PAHs. Total PAH concentrations increased from 33.11-36.77μg/kg to 45.12-58.04μg/kg in 26 crude oil samples, while those in 26 refined oil samples increased from 16.52-20.02μg/kg to 25.73-40.01μg/kg. Acid value (AV) and peroxide value (POV) also showed an increase during the storage process from 0.08-0.92mg/kg to 0.33-2.98mg/kg, and from 0.08-0.12mmol/kg to 0.33-3.45mmol/kg in 52 tested oils, respectively. AV and POV were within the regulatory limits of China after storage for 270days. However, concentrations of 16 PAHs in all tested oils exceeded 25μg/kg. The results indicated PAHs and OPAHs formation was better inhibited in oils stored at lower temperature.