Study On Degradation Of Aflatoxin B₁ By Instant Catapult Steam Explosion

Aflatoxin?AFT?is the most toxic biotoxin found in contaminated agricultural products so far,which has strong mutagenicity,carcinogenesis and teratogenicity to humans and animals.Aflatoxin B₁?AFB₁?is the most toxic,therefore it is used as an evaluation indicator for AFT.In this study,based on Instant Catapult Steam Explosion,the key explosion technical parameters were optimized to degrade efficiently AFB₁ in corn straw and peanut cake.By UPLC-TOF-MS/MS the degradation products and the degradation pathway of AFB₁ in corn straw were analyzed.The biological toxicity of AFB₁ degradation products in corn straw and peanut cake was evaluated by MTT assay.It provided a theoretical basis for harmless and high value utilization of crop resources and laid a theoretical foundation for further promoting feed and food safety in China.The main findings were as follows:?1?Different explosion conditions were used to degrade AFB₁ in corn straw.The results showed that the degradation rate of AFB₁ reached 98.4% at 2.4 MPa for 60 s,but when the treatment time was extend to140 s,AFB₁ in corn straw was completely removed and the degradation rate could reach 100%.Based on this condition,five degradation products were produced,whose molecular formulae were A?C17H8O6?,B?C17H14O6?,C?C16H8O5?,D?C17H14O7?,E?C17H16O9?respectively.Moreover,two degradation pathways were analyzed,and the first was the condensation-addition degradation pathway,which mainly included the addition reaction of water molecules,the hydrolysis and oxidation of lactose and hemiacetal,and the second was the dehydrogenation and degradation pathway,which mainly involved in the dehydrogenation reaction and the formation of ester-bonded carbonyl groups.Also,the degradation products and degradation pathways of AFB₁ under different explosion conditions were compared and analyzed,and the results showed that with the increase of explosion pressure,at the same pressure holding time,the number of AFB₁ degradation products increased to result in form a new degradation pathway,and AFB₁ was inclined to form degradation product A by aromatization;under the same explosion pressure,with the increase of pressure holding time,AFB₁ was apt to be degraded to product B.Based on MTT test,the results showed that when drug concentration was at 0.039 ?g/m L and 0.156 ?g/m L,the cell fatality rate of the sample?the corn straw after ICSE adding AFB₁?was far greater than that of the sample?the degradation products of AFB₁ in corn straw after ICSE?,and the lethality rate of degradation products decreased by 79.65% and 27.28% respectively,which illuminated that the cytotoxicity of degradation products decreased significantly.?2?Based on Instant Catapult Steam Explosion AFB₁ in peanut cakes was removed.Considering its nutritive value and energy consumption,1.2 Mpa for 200 s was selected as the optimum explosion conditions,and the degradation rate of AFB₁ was 79.03% at this condition.Furthermore when 4% ammonium hydroxide was combined Instant Catapult Steam Explosion treatmentat 1.2 Mpa for 200 s,the degradation rate of AFB₁ in peanut cake was up to 91.48%.After treatment the crude protein detected in the peanut cake was increased by 10.67%,but other nutrients were not significantly changed.The cytotoxicity of peanut cake after steam explosion treatment was evaluated based on MTT assay.The results showed that 2.5 g of peanut cake contaminated with AFB₁ caused 5.79% cells death.However the peanut cake after steam explosion treatment promoted cells growth,which indicated the degradation products of AFB₁ is low-toxic or non-toxic.