Further evidence on the removal of polycyclic aromatic hydrocarbons (PAHs) during refining of olive pomace oil

Abstract

Influences of chemical refining parameters on the removal of 15 polycyclic aromatic hydrocarbons (PAHs) from a list of 16 EPA-priority pollutant PAHs are investigated. For this purpose, various process conditions for each refining stages (degumming, neutralization, bleaching, and deodorization) are applied to crude olive pomace oil and the changes in PAH concentrations are monitored using a high performance liquid chromatography with florescence detector. Results show that total PAH content of the oil is reduced effectively through all refining stages. Degumming has considerable effects on removal of individual PAHs depending upon water or acid application while the most significant reduction in total PAH is achieved when 1% water is used. Neutralization has a significant impact on removal of PAHs from the oil, however, washing steps have limited effects. Using various amounts (0.3, 0.6, and 0.9%) of activated carbon in 3% of bleaching earth are more effective on the reduction of total and heavy PAHs from the oil and the most reduction is achieved when 0.9% activated carbon is used. Deodorization is effective mainly on decreases in light PAHs while temperature incrementation does not have any significant impact on the reduction in total PAH content.

Practical Applications: Olive pomace oil may include high amounts of PAHs. Because of their potential carcinogenic character, removal of PAHs from the oils has a great importance for oil acceptability. Results of this study provide information about the effects of process conditions of degumming, neutralization, bleaching, and deodorization on PAH reduction in olive pomace oil. These results might open up new process strategies in production of high quality olive pomace oil via refining.