Effect of Production Process on Concentration of Lead and Arsenic in Sunflower Oil

Background and Safety control in edible oil industry regarding its pollution to heavy metals is one of the most important factors in maintaining the health of people and assuring their safety. This research aimed at evaluating the effect of production process of sunflower oil on its lead and arsenic content. All sunflower samples were collected from a local factory during various stages of production process including raw oil, neutralization, de-coloring, de-odoring, winterizing and packaging. Sample preparation was performed by closed-vessel microwave extraction and lead and arsenic were analyzed by graphite furnace and vapor hydride atomic adsorption spectrometry, respectively. The mean concentration of lead and arsenic in sunflower oil in various stages of production process were 2.9±0.2 and 0.5±0.1 for raw oil, <0.1 and 0.2±0.1 for neutralized oil, 2.0±0.7 and 0.8±0.1 for de-coloring oil, 0.2±0.1 and <0.1 for de-odoring oil, 1.3±0.1 and 0.9±0.1 for winterized oil, and 5.1±0.3 and 1.6±0.3 µg/Kg for packaged oil, respectively. Neutralizing the oil and its de-odoring reduced the concentration of lead and arseneic, while de-coloring and winterizing the oil increased the concentration of these metals in oil. It seems that heavy metal impurities in Bentonite soil and poor coat conditions of oil reservoirs were the major factors in increasing the concentration of lead and arsenic in de-coloring and packaging phases. Also, saturated glyceride and waxes which are coming out in winterizing phase has a major contribution in polluting the oil by heavy metals.