Impact of refining on the levels of 4-hydroxy-trans-alkenals, parent and oxygenated polycyclic aromatic hydrocarbons in soybean and rapeseed oils

摘要

4-Hydroxy-2-trans-hexenal (4-HHE), 4-hydroxy-2-trans-nonenal (4-HNE), polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (oxy-PAHs) are harmful compounds that commonly occur in edible oils. In this study, we assessed the levels of these compounds in soybean and rapeseed oils during refining. The concentrations of 4-HHE, 4-HNE, 16 PAHs and five oxy-PAHs in soybean oil decreased from 16.27, 644.19, 48.72 and 20.04 mu g/kg to 5.65, 260.01, 19.71 and 2.04 mu g/kg, respectively, after refining. In rapeseed oil they decreased from 21.46, 246.44, 38.02 and 6.56 mu g/kg to 0.00, 37.35, 17.25 and 2.04 mu g/kg, respectively. Furthermore, the compounds were sequentially reduced throughout the refining process. The most significant reduction in PAHs was attributed to neutralization (up to 54.79% of the total reduction), while the most significant reduction in oxy-PAHs was attributed to bleaching (up to 84.83% of the total reduction), which also notably reduced 4-HHE and 4-HNE in the soybean oil refining. These results may be helpful for quality and process control with regards to minimizing the levels of harmful compounds in edible oils. (C) 2016 Elsevier Ltd. All rights reserved.