Study on the effect of activated carbon with bleaching earth on the reduction of polycyclic aromatic hydrocarbons (PAHs) in bleached soybean oil

Considering the importance of bleaching earth with activated carbon for reducing the Polycyclic aromatic hydrocarbons (PAHs) as an important chemical contaminant, this study was conducted to confirm the effects of the bleaching process on the reduction or elimination of the BαP index and 4 PAH (BαA, CHR, BβF, BαP) contents in soybean oil. The bleaching process was carried out with different amounts of bleaching earth (1% w/w) and activated carbon (0.1% up to 0.5% w/w). A HPLC/FLD device was employed to determine the PAHs in the oil samples after undergoing extraction and clean-up procedures. The results of linearity indicated that there was a linear response with high linear regression coefficients of determination for all the 4 PAHs analyzed. (R2 > 0.9950). Furthermore, the recovery percentage was calculated from 83.8% to 106.2%; LOD and LOQ were 0.06–0.2 μgkg−1 and 0.2–0.61 μgkg−1, respectively. An analysis of the PAH contents indicated that the bleaching process, including a 0.27% to 0.5% w/w activated carbon application led to the elimination of the PAH content. Since vegetable oils have been shown to be the major sources of PAHs in the diet, the industrial use of activated carbon during the bleaching of vegetable oils is highly recommended.