Study On The Removal Of Aflatoxin B₁in Peanut Meal By Electron Beam

Peanut is the main oil crops in China, and the yield of peanut is at the top of all kinds ofoil seeds. Every year, eight million tons of peanut was used for oil extraction in China. Theamount of peanut meal is about three million tons as the by-product of oil extraction. Peanutmeal is rich in nutrition, although peanut is easy to be infected by fungi. The generation offungi aflatoxins limits the application of peanut meal severely. Electron beam (EB) irradiationis an advanced and novel technology for the removal of aflatoxin, and it has the advantages ofhigh efficiency, environmental protection, safety, little impact on the products degradation. Itis widely used in food sterilization, detoxification and preservation. EB has been proved as aneffective method to degradate aflatoxin in simple system. However, the mechanism, safety aneffects of EB application for aflatoxion removal on peanut meal quantity were unclear. In thisresearch, aflatoxin B1(AFB1) was selected as the research object, and its degradation behavior,products and pathway in water and peanut meal were studied. The Ames test and cytotoxicityexperiment were applied to analysis the mutagenesis and toxicity of EB degradation productsof AFB1, also the effects of EB detoxification process on peanut meal quality were assessed.Firstly, the EB degradation behavior at different dose, initial concentration, thickness andmoisture content was studied. The results showed that the degradation of AFB1in peanut mealwas related to radiation dose, initial concentration, thickness of solid meal and moisturecontent. Under the dosage of4kGy, the degradation rate of AFB1solution was80%, whichincreased to92%after8kGy EB irradiation. In the experimental ranges, with the increased ofradiation dose, initial concentration and moisture content of solid meal, the degradation rateof AFB1in peanut meal increased. However, with the increasing of thickness of solid meal,the degradation rate decreased.As shown in ultra-performance liquid chromatography quadrupole time-of-flight massspectrometry (UPLC-Q-TOF/MS) analysis, the solution of AFB1in water irradiated by EBdegraded to five kinds of major products. The products were P1(C16H12O7), P2(C16H16O6), P3(C17H14O8), P4(C15H12O6), P5(C17H12O7), respectively. Hydrogen abstraction reaction at citeC(6a)-O(7) along with limination reactions at cite C(1)-C(2) and C(3)-C(3a) generated P4.Addition reaction at cite C(8)-C(9) of AFB1lead to the generation of P3. P1, P2and P5weregenerated by limination and reduction reactons from P3. The main structures of these fiveproductes were similar to that of AFB1.The EB degradation reaction in peanut meal was severe. It is proposed that AFB1wasoxidized to minor molecular substances rapidly after EB irradiation.In addition, the Ames test and cytotoxicity experiment were used to evaluate themutagenesis and toxicity of EB degradation products of AFB1in water and peanut meal. Theresults indicated that the cell viability of AFB1treated cell, used as positive control, decreased72.44%. The cell viability of degradation products in water treated cell reduced about18.61%,which mutagenicity decreased more than50%. The mutagenesis and toxicity of AFB1degradation products in water after EB treatment decreased significantly (p＜0.001), whilethe degradation products in peanut meal were not toxic (p＜0.001). Finally, the contents of crude fat, protein, amino acids, total carbohydrates, reducingsugar, total flavonoid, ash and fatty acids were selected as the indexes to study the effect ofelectron beam from accelerator for removing aflatoxion B1on the quality of peanut meal. Theresults indicated that the content of reducing sugar, total flavonoid, palmitic acid, linoleic acidand oleic acid increased slightly with irradiation dosages, with the eicosanoic acid contentdecreased. The irradiation had no significant effects on the content of crude fat, protein, totalamino acids, total carbohydrates and ash after the treatment by different dosages of electronbeams (p＞0.05). EB irradiation could be applied for detoxification with few bad effects onthe quality of peanut meal.