The Content Of Lead In Edible Oil

The security of vegetable oil is related to the major issues of human health. In this article,we researched the content of lead in vegetable oilseeds and oils. We researched a simplepretreatment method of edible oil by microemulsion sampling, analysis the source of lead andits residues, change condition through to determined the content of lead in vegetable oilseedsand oils. At the same time, we compared the content of lead which used different level andadditives processing aid in the process of fats and oils refining. The major contents aredescribed as follows:（1） A simple method was proposed for the rapid determination of calcium, magnesium andlead in edible oil by microemulsion sampling combined with FAAS and GFAAS. Theconditions for microemulsion formation and working parameters were optimized in thisresearch. The results showed that the recoveries obtained by microemulsion sampling were inthe range of94%～116%. And the results obtained by microemulsion sampling were inaccord with that obtained from digested sample with dry ashing method which the nationalstandard proposed and it was applied to determine the content of lead in edible oil.（2） Through to determined the content of lead in oilseeds and oils in different productionareas and processing technology, the result showed there are9oilsdeeds’ lead were exceed thenational standard in13determined oilsdeeds, the multiple of exceed standard was1.2～12.3times and the over standard rate was69.2%. Only one oil sample’ s lead was exceed in26oilsamples and the multiple of exceed standard was1.3times. It illustration that through entiretyrefining of oil, the content of lead in refined oil can meet the standard. But the content of leadin refined oil maybe exceed the standard when the lead was too high in oilseeds or therefining was incomplete.（3） we investigated the content of lead in processing aid（H|₃PO₄, NaOH, activated clay andactivated carbon） which used in oil refined. It was found that the content of lead in industrialgrade H|₃PO₄and NaOH are2.5and2.1times than food grade H|₃PO₄and NaOH, the contentof lead in activated clay and activated carbon are2265.4μg/kg and3154.6μg/kg respectively.We determined the content of lead in soybean oil, canola oil and rice bran oil which usedifferent grade and additives processing aid during oil refining, the result showed the contentof lead in oil which use industrial grade processing aid is1.2～2.8times than use food grade processing aid; use5%activated clay is the best optimal during decoloring process. Overall,the content of lead in oil was decreased gradually with the processing carried out. Comparedactivated clay, activated carbon, activated clay&activated carbon removal lead to two canolaoil which the content of lead exceed2.3and4.3times, the result showed activated clay is thebest optimal, and the more the lead in oil, the more activated clay need. To the two canola oil,the best additive of activated clay is7%and10%respectively, but the bleached oil’s quality islower, only accord with grade four oil’s standard.