The Effect of Purification Process on Heavy Metals in Soyabean Oil

Heavy metals are important elements in the oil quality and determine the freshness, shelf life, storage ability and also affect the human health nutritionally. Therefore determination of heavy metals due to their effect concerned with the rate of oxidation is quite essential.
In this study, concentrations of heavy metals including Lead, Cadmium, Mercury and Arsenic during different stages of soya bean oil refining were studied using atomic absorption spectrometry.
The results indicated that the most common stage in Arsenic reduction is the neutralization stage that eliminates 60% of the total Arsenic content. The main stage in Cadmium reduction is the deodorization that reduces 40% of the initial Cadmium. Major part of Mercury reduction is concerned with metal scavenger addition that is referred to chelating activity of citric acid that might be added during bleaching and deodorization stages. Neutralization has separation role and causes the reduction of lead as soap.
The results showed that neutralization and the addition of scavengers are the main parts in heavy metals reduction.