Source And Control Of Benzo(a)pyrene In Sesame Oil

Sesame oil is a traditional flavor oil which is very popular all over the world. It is oftenexposed to benzo(a)pyrene pollution in the process of planting, processing, transportationand cooking. However, the source and control of benzo(a)pyrene in sesame oil was studiedlittle.In this paper, the method of determination of benzo(a)pyrene content in the sesame oilis established. The key steps which affect benzo(a)pyrene formation in sesame oil wasfound. At the same time, an economic and practical method about reduction ofbenzo(a)pyrene content in sesame oil was studied, which is very significant to improveproduct quality of sesame oil and promote the sesame industry development. Main contentsof this paper included:(1) A method for determination of benzo(a)pyrene content in the sesame oil wasestablished. Refer to the GB/T22509-2008and international standard method of ISO15302-2007, samples were dissolved in hexane, then benzo(a)pyrene was adsorbed onneutral alumina columns, and eluted with hexane to remove benzo(a)pyrene to solution anddetermined by HPLC using fluorescence detector. The linear relationship between peak areaof HPLC and concentration of benzo(a)pyrene was obtained at the range of0.1～20μg/L.The rate of recovery of sesame oil by HPLC method ranged from73.2%to93.2%, and RSD(n=5) value were from2.2%to4.2%.The detection limit was0.5μg/kg. The method isaccurate and stable, and is suitable for determining benzo (a) pyrene in the sesame oil.(2) The source of benzo(a)pyrene in sesame oil was studied. The samples were gotfrom different processing procedures, and the contents of benzo (a) pyrene were detected.The results showed that in the whole processing of expression method of sesame oil, thecontents of benzo (a) pyrene were very little, and changed a bit. In the exacting process forthe production of sesame oil, the contents of benzo (a) pyrene of oil were high and thebenzo (a) pyrene mainly came from sesame cake. Although the sesame oil wasdeacidificated, bleached, degummed and deodorizated in the refining process, and thecontents of benzo (a) pyrene were almost not reduced, and the content of benzo (a) pyreneof refined sesame oil was still high as a result. (3) The method for reduction of benzo(a)pyrene in sesame oil was established. Theeffects of the amount of activated carbon, activated clay content, adsorption time andabsorption temperature on reducing benzo (a) pyrene of the sesame oil were studied throughexperiment. Optimizing by orthogonal experiments and considering the sesame oil andother quality indicators, the optimal method for reducing benzo (a) pyrene content of thesesame oil was obtained. The optimum conditions of the production of dark sesame oil was1%of the amount of activated clay,0.8%of the amount of activated carbon,45min ofadsorption time,80℃of adsorption temperature. A second absorption technology wasnecessary in the production of light-colored sesame oil, and the optimum conditions ofproduction of light-colored sesame oil was5%of the amount of activated clay,0.8%ofthe amount of activated carbon,45min of adsorption time,80℃of adsorption temperature.Benzo (a) pyrene content of the sesame oil could be reduced by85.1%and86.2%on theoptimum conditions and was less than2μg/kg to meet EU standards.