CHANGES IN PAH LEVELS DURING PRODUCTION OF RAPESEED-OIL

The influence of technological operations during rape-seed oil product ion on polycyclic aromatic hydrocarbon (PAH) concentrations in by-prod ucts, intermediate and final ails was evaluated The decrease of light PAHs, benz(a)anthracene and benzo(a)pyrene during processing of crude oil to the deodorized product was significant at the 95% confidence in terval in most batches analysed. Deodorization and alkali-refining wer e the steps contributing most to the PAH decrease. The I relationship between PAH levels in rapeseed (and consequently in refined oil) and t he duration of storage period was studied. The contamination of raw ma terial processed a short time after. harvesting was significantly high er than that of the rapeseed stored in silos for several months. Analy ses of rapeseed samples, which were re-purified in rite laboratory, re vealed that solid particles, which contaminate rapeseed during harvest ing, initial treatment, transport and storage, contributed to PAH cont amination to the extent of 36% (light PAHs) to 64% (heavy PAHs) on ave rage. Further experiments demonstrated that PAHs in re-purified rapese ed were concentrated in the cuticular layer, because they were removed well from the whole seeds by simple rinsing with organic solvent in a n ultrasonic bath without losses of rapeseed oil. Alternative expressi ons of total PAH contamination (e.g. various PAH groups and/or differe ntly defined B(a)P toxic equivalents) al e discussed and their effect on drawing conclusions about PAH elimination rate has been demonstrate d.