The Effect And Detoxification Control Of Vomitoxin DON In Contaminated Grains By Chlorine Dioxide And Ozone

Deoxynivalenol,also called vomitoxin,is a kind of secondary metabolite generated by Fusarium graminearum.F.graminearum can infect food crops such as wheat,corn,results in Fusarium head blight and then produces toxins.The synthesis of vomitoxin were affected by nitrogen,pH and environmental stress.In recent years,the pollution situation of DON on grain became very serious in the worldwide.With stable chemical property,intake DON can cause serious damage to the health of people and livestock.The pollution of DON in grain has become the key issue that needs to be solved.Therefore,it is imperative to study the prevention and control of vomitoxin in grain.Commonly,the mycotoxin are often detoxificated from itself not from the source.The paper combines with food processing,studied the inhibition effect of ClO₂ aqueous solution on the growth and toxicity of the Fusarium graminearum.The expression and regulation of toxin-producing genes were studied by chlorine dioxide.The inhibitory mechanism of Fusarium graminearum metabolism changes induced by ClO₂ stressing effect was analyzed.Combined with the system of ozone water,studied the effects and by-products of ozone treatment on the degradation of DON in contaminated cereals and establish an monitoring method for intermediate products.The process of infected through simulated production by F.graminearum,and then evaluated the product before and after degradation in vivo and in vitro methods.The results confirmed the feasibility of chlorine dioxide and ozone water treatment in the control of vomitoxin and to provide theoretical evidences for detoxification and control of vomitoxin DON.The main results are detailed below.Firstly,Study on the inhibition effect and antagonistic mechanism of F.graminearum growth and spore germination by ClO₂ aqueous solution.By studying the different concentration of?10,20,40 mg/L?of ClO₂ aqueous solution inhibition effect of growth cycle for F7875.The growth of F.graminearum was significantly inhibited by the ClO₂ aqueous solution in 40 mg/L concentration.Study on the inhibition of spore germination of F.graminearum by ClO₂ aqueous solution,and then fitting kinetics curves under different concentration of ClO_2.Presoaking wheat first,solid-liquid ratio was 1:2,the wheat was treated with a concentration of 100 mg/L of ClO₂ for 30 min by means of optimization test.It could effectively remove the wheat surface and the insidious of F.graminearum and spores.Secondly,the effects of ClO₂ on the genetic and metabolomic mechanism effects of F.graminearum were deeply analyzed.Analysis different concentration ClO₂ influence on F7875 in the process of liquid fermentation culture.With the increased concentration of ClO₂?from 0.5 to 1 mg/L?,the production of DON showed a decreasing trend.By optimizing reaction conditions of PCR,The TRI5 gene of the F7875 was verified as 260 bp.Through qRT–PCR experiment,under 0.5-1 mg/L concentration of ClO₂,the TRI5 gene of F7875 showed a decline trend during the period of treatment,it led to a decrease of DON.Through metabolic analysis,the metabolites of F7875 were significantly altered after ClO₂ stress effected.48 and56 different metabolites were screened.The changes of glycine and serine metabolism and arginine and proline metabolism pathway were induced,resulting the metabolic changes of proline,ornithine,aspartic acid,serine,threonine,and some sugars.Thirdly,combination with the ozone water system,Study of degradation products and intermediate test methods from the residue reduction and control of the DON in the contaminated grains.Build an ozone device to degrade DON,10 mg/L of DON was degraded by 80 mg/L aqueous ozone,the degradation rate was 83%in 7 min.Study on the kinetic studies of DON by aqueous ozone,the dynamic curves of different concentrations of DON?1,5,10,20 mg/L?were proposed.The R² were 0.91?0.87?0.93?0.85,respectively.In the concentration of 80 mg/L aqueous ozone,solid-liquid ratio was 1:7,the wheat was treated of for 10 min by means of optimization test.After degradation,the degradation rate of DON-contaminated wheat?2.18 mg/L?,corn?2.93 mg/L?and bran?3.70 mg/L?were 74.86%,70.65%,76.21%,respectively.The material was analyzed in the degradation process by UPLC/Q-TOF.Two degradation products of DON were detected,the[M+H]⁺were 311.0171and 313.0149,respectively.The chemical formulas of degradation products are deduced as C₁₅O₇H₂₀ and C₁₅O₇H₁₈.The study have found that the two degradation products were intermediate,and that the product would disappear after degradation in 24-48 h.According to product secondary quality spectrum ion information,the MRM ion channel was set by UPLC TQD MS.The DON and two degradation products could be simultaneous detection by the MRM ion channel detection methods.It could provides theoretical basis for monitoring the samples.Fourthly,the seed germination experiment and cytotoxicity test were used to evaluate the safety of degradation products.Cytotoxicity test demonstrated that 10 mg/L DON can significantly inhibit the proliferation of HepG2 cells and there was no significant effect on HepG2 growth after degradation.Active oxygen test showed that 1-10 mg/L concentration of DON stimulates HepG2 and produces lots of reactive oxygen free radicals,the fluorescence was obviously.But the fluorescence of cell fluorescence was significantly reduced after degradation.After ozone degradation,the cytotoxicity of DON was significantly reduced.Plant seed germination experiment shows that the concentration of 1 mg/L DON can significantly inhibit the germination of green bean seeds.However,the degradation of the green bean was not significantly inhibited after the ozone degradation.It showed that the toxicity of DON in wheat after degradation by ozone was significantly reduced.Finally,In order to further analyze the safety of the treatment,simulate the process of toxin contamination,establish pollution corn animal experiment evaluation method before and after processing.The evaluation test was carried out in accordance with the national standard 28 days.Inoculation of F7875 of the F.graminearum in corn grain was inoculated to the corn kernels to simulate the infection and toxicity test.The contaminated corn before and after the ozone degradation was formulated and made into mice feed to simulate the daily feeding experiment.Compared with the control group,the liver and kidney organs of the mice were swollen in the dose group,ratio of viscera increased.Abnormal elevation of ALT and AST in the liver function index.The content of total protein and albumin decreased significantly.After treatment,the toxicity effect was improved,the difference was not significant compared to the control group.At the same time,the results of tissue biopsy showed that the toxin group could make the liver,kidney and thymic tissue in mice produce obvious pathological changes,there was no significant difference between the treatment group and the blank group.The above results showed that DON contaminated maize was more toxic to mice.The toxic effect of ozonation on mice was reduced after ozone degradation contaminated DON.In conclusion,ClO₂ was used to inhibit the growth of scythe and the production of toxic genes in this paper.It is shown that ClO₂ can effectively prevent the growth of F.graminearum and the production of DON in grains.At the same time,the residual effects of aqueous ozone degradation DON were significant.The intermediate product detection method was established and carried out the safety evaluation.The experiment result shows that the effect of ClO₂ and ozone treatment on the reduction and control of DON in grain,the experimental results provide reference and technical support for control of DON.