The Rapid Determination,formation And Mitigation Strategies Of Benzo (a) Pyrene In Vegetable Oils

Benzo（a）pyrene is one of the three major carcinogens identified by World Health Organization.Benzo（a）pyrene is the most toxic polycyclic aromatic hydrocarbons,having strong carcinogenic,teratogenic and mutagenic effect on human body by skin contacting,air breathing,eating and drinking.Benzo（a）pyrene is often found in polluted air,drinking water and foods,especially the food barbecued,fried and smoked.Therefore,it is the hotspot that accurately and rapidly determining the benzo（a）pyrene,and preventing the pollution and formation of benzo（a）pyrene in food.The aim of the thesis is to study the factors affecting the formation of benzo（a）pyrene in vegetable oils,removal effect of the benzo（a）pyrene in vegetable oils by adsorption method,and a system of the formation of benzo（a）pyrene in food.And a rapid and sensitive electrochemical nano sensor for detection of benzo（a）pyrene in vegetable oils has been established.1)A Chitosan-Graphene/Glassy Carbon Electrode（CS-GS/GCE）were constructed for investigating the electrochemical properties of benzo（a）pyrene,and a rapid and sensitive method for determination of benzo（a）pyrene in vegetable oils has been established.A well-defined oxidation peak was observed at 1.0 V and no reduction peak appeared,which indicated that the process was irreversible;The experimental conditions of CS-GS/GCE for determination of benzo（a）pyrene in vegetable oils were optimized.At the optimal conditions,the oxidation peak currents linearly increased with concentration of benzo（a）pyrene in the range of 0～100 nmol/L(I_P=0.1162 C_{Ba P}+22.9262,R²=0.9978),with the detection limit of 0.103 nmol/L（S/N=3）.This method was applied to determine the benzo（a）pyrene in vegetable oil with the recovery rate of 98.51%～100.57%,and the results were well agreed with High Performance Liquid Chromatography.Therefore this method was feasible for the determination of benzo（a）pyrene in vegetable oils,with high sensitivity,simple operation and low cost.2)A reaction system was established,employing vegetable oils as the subject,to research the factors affecting the formation of benzo（a）pyrene in food.The formation of benzo（a）pyrene in vegetable oils was preliminarily studied by controlling the baking temperature,baking time,its composition and antioxidants.The results indicated that the content of benzo（a）pyrene in vegetable oils had positive correlation with baking temperature and baking time.The growth rate of benzo（a）pyrene in rapeseed oil was higher than that in soybean oil,which may be related to the composition of fatty acids in them.In addition,protein,starch,glucose and sucrose were positively correlated with benzo（a）pyrene in vegetable oils,and the order of effect was glucose,sucrose,protein and starch in turn.Vitamin E,tert butyl hydroquinone and propyl gallate can inhibit the formation of benzo（a）pyrene in vegetable oils,and the inhibitory effect of the three was not very different.3)The effect of roasting conditions on the formation of benzo（a）pyrene and the removal efficiency of benzo（a）pyrene in vegetable oils by adsorption method were studied.To avoid the overproof of benzo（a）pyrene in vegetable oils,the baking condition should not exceed 180℃,30 min for white sesame,and 160℃,30 min for walnut.The removal efficiency of benzo（a）pyrene was researched by adsorbents,and the result demonstrated that when the dosage of YS-900 food grade activated carbon was 2%,the removal rate of benzo（a）pyrene was 89.04%in sesame oil and when the dosage of YS-900 food grade activated carbon was 0.5%,the removal rate of benzo（a）pyrene was 85.55%in peanut oil;when the amount of active clay was 5%,the removal rate of benzo（a）pyrene in sesame oil and peanut oil was only 28.16%and 31.46%,respectively;when the dosage of mixed adsorbent was 1.4%+3%（YS-900 food grade activated carbon+activated clay）,the removal rate of benzo（a）pyrene in sesame oil was 89.18%,and when the dosage of mixed adsorbent was 0.5%+3%,the removal rate of benzo（a）pyrene in peanut oil was 88.88%.Therefore,the benzo（a）pyrene in vegetable oils could be eliminated effectively by adsorption method,and the removal efficiency of the mixed adsorbent is better than that of a single adsorbent.