The Degradation Of Aflatoxin B₁ In Peanut Oil And Its Safety Evaluation

Aflatoxin (AFT) is a kind of secondary metabolites generated by some fungi such as Aspergillus flavus, Aspergillus parasiticus,etc. And Aflatoxin Bi which was endow the title of "level 1 carcinogen" by IARC. has the strongest toxicity. It can cause caner, malformation, mutation.AFT pollution is the main reason which affecting consumption safety and export trade of peanut and its products.So looking for a rapid detection technology and detoxifcation method is the most pressing issue currently.This study takes the Aflatoxin Bi in peanut oil as research object, trying to build a rapid detection technology of enzyme immunoassay. And at the same time studying the detoxification effect when processing Aflatoxin Bi by 60Co irradiation and microwave irradiation, then evaluate the safety of the processed peanut oil by the main physical and chemical indicators and degradation products.Single factor experiment and orthogonal experiment which effect AFB1-O. Synthesis were carried out and the results of the study are as follows:The highest oximation rate reached 96.7% when the initial mass ratio is AFB1/CMO= 1:2, the reaction time is 5h, the reaction temperature is 65℃; The pecking order of some factors which affecting oximation rate are initial mass ratio of AFBi/CMO> time> reaction temperature. The optimal synthesis conditions of AFB1-BSA (complete antigen):The initial mole ratio of AFB1/CMO is 30:l,the temperature is 23℃, then shaking reaction 20h in the dark environment.The optimal synthesis conditions of AFB1-OVA (envelope antigen):The initial mole ratio of cross-linking agent EDC/NHS is 4:1,the temperature is 23℃, then reaction 12h in the dark environment.Then obtained antibody by artificial antigen immune the mice. And the titer of polyclonal antibody is 1:3200; half inhibitory concentration/C50=3.25ng/mL; the cross-reactivity rate with AFMi is 3.1%, the cross-reactivity rate with ZEN, deoxynivalenol, DON were less than 0.28%.We diluted the antibodies, and then obtained the optimal working concentration by chessboard titration, namely the antigen antibody dilution 13000 and enzymes diluted 16000 times. From the experimental results we know the optimum working conditions parameters of Aflatoxin B1 ELISA kits are follows:Antibody coated at 4℃ for 12h, gelatin closed at 4℃ for 12h, the specific reaction of antigens and antibodies proceed 30min in the dark environment, the chromogenic reaction proceed 10min at room temperature. The results of accelerate destructive experiment show that the kit can be stored at 4℃ for 30 days, ELISA kit was no significant difference when compared with the HPLC test results. The pretreatment method of sample is simple and effective, then extracting by organic solvent, the measurement results is similar with the national standard method.The degradation experiment results of Aflatoxin Bi show that as irradiation dose of 60Co increases, the degradation rate increases. When the initial content of AFBi is less than 25ppb, the 10kGy irradiation dose can completely remove AFB1 in peanut oil. The single factor experiment of microwave radiation degradation result show that microwave irradiation time impact most, the second is the microwave power, the third is the initial content of AFBi.And three factors affect significantly. We obtained optimum conditions parameters of AFB1 under the analysis of response surface experiment result. That is the initial content of AFB1 is 13.72ppb, the microwave power is 803.98W, the microwave irradiation time is 10.27min, and the predictive value of degradation rate of AFB1 is 96.0055%. Under the optimal treatment conditions of AFB1 by microwave degradation, the main physical and chemical indicators of peanut like acid value, iodine value, peroxide value, vitamin E and trans fatty acids were not changed significantly; comply with relevant national standards.From the Ames experiment we know that there is a significant dose-response relationship between the dose of AFB1 and the reverse mutation number of control group(AFB1 that undegraded) adding S9(metabolic activation system);And the difference between the reverse mutation number of the positive control group and the spontaneous reverse mutation group can reach significant (a<0.05) or extremely significant (b<0.01) only when the control group has added S9 (5ng dose group is exception). Whether or not to add S9, the reverse mutation numbers of the positive group (The microwave degradation products of AFB1) and the spontaneous reverse mutation group have no significant difference (p>0.05). This can prove that the toxicity in degradation products of AFB1 in peanut has completely disappeared when degraded by microwave irradiation. And we know that there is not a dose-response relationship among AFB1 degradation products TA98, TA100 and TA102 after microwave degradation, in another words, the degradation products of AFBi degraded by microwave degradation has not mutagenicity on salmonella typhimurium (his-).