Study On The Effect Of Ozone On The Preservation Of Fresh Waxy Corn And The Inhibition Of Ear Rot Pathogens

The optimum harvesting period of Zea mays L.sinensis Kulesh was determined by research,and the post-harvest fresh waxy corn was fumigated with different concentrations of ozone to explore the quality of postharvest storage of fresh waxy corn.The effects of Fusarium graminearum and Fusarium oxysporum,the pathogens of postharvest rot of fresh glutinous corn,were studied under different conditions.Different concentration of ozone treatment explored its effect on the spore germination rate,sporulation,mycelial growth and morphological changes of pathogenic bacteria.By measuring the dry weight of mycelium,cell membrane permeability and cell leaching soluble sugar content to study the antibacterial mechanism of ozone.The research results are as follows:1.Based on the sensory and cooking quality of fresh waxy corn,the optimum harvesting period for fresh waxy corn is 22 to 24 days(seeding time is 87 to 89 days).Green and yellow are suitable,the seeds are full,the color is bright,the cooking tastes sweet and sticky,and has a unique taste of fresh corn during this period.The grain and alfalfa leaves have a high moisture content when harvested 22 to 24 days after pollination.The proper moisture guarantees the taste of fresh waxy corn and reduces the outward water gradient of the grain,moreover reducing water loss.The weight loss rate of corn is small.2.Ozone treatment significantly improved the nutritional quality and sensory quality of fresh waxy corn during postharvest storage and preservation.Studies have shown that ozone treatment can reduce the respiratory intensity of fresh corn kernels,both of soluble sugar and starch content reduced to varying degrees,but still maintain a high level,while soluble protein content is significantly higher than the control group;when waxy corn stored at room temperature for 5 days,the mass loss of 90mg/m3 ozone-treated was 5.99±0.02%,which was 0.56%lower than the control group,and the water content was 56.81±0.03%,which was significantly higher than the control group.Ozone treatment has a certain effect on ensuring the nutritional quality of corn during storageAt the same time,ozone treatment can reduce the production of MDA.Compared with the control group,the MDA content of the 45 mg/m3 ozone treatment group is reduced by 0.112?mol/g,which is the best.Flavonoids as a metabolite of corn,they can delay tissue aging and enhance stress resistance.In the 5th day,the flavonoid contents in the 90 mg/m3 ozone treatment group and 135 mg/m3 ozone treatment group were 2.54±0.03%and 2.72±0.04%,respectively,which were significantly higher than those in the control group,while the flavonoid contents in the 45 mg/m3 ozone treatment group and the control group were the lowest and the difference was not significant.3.The effects of different concentrations of ozone on Fusarium graminearum and Fusarium oxysporum were studied.Pathogen spores,colony expansion,hyphal morphology and cell membrane permeability were studied,and the pathogenic mechanism of ozone was discussed.Ozone treatment can effectively inhibit the spore germination rate and sporulation of Fusarium graminearum,which is negatively correlated with ozone concentration.The lowest sporulation in the 135 mg/m~3 ozone content treatment group was 32.69±1.33×10~7/dish,which was the control group.27.56%;ozone treatment can significantly inhibit the expansion of colonies and achieve the purpose of inhibiting their growth and reproduction;the dry weight of mycelium in the ozone treatment group is low,the mycelium is decreased,and the tangled morphology is abnormal;at the same time,ozone treatment leads to the cell membrane permeability of the cells.The soluble sugar content in the cell contents is increased,the metabolism is unbalanced,and the cells cannot grow or even die.The relative conductivity of the 135 mg/m~3 ozone content treatment group and the soluble sugar content in the mycelial exudate were the highest.Therefore,ozone treatment can inhibit the colony expansion of Fusarium graminearum,and the 135 mg/m~3treatment group has the strongest inhibitory effect on pathogenic bacteria.The effects of different concentrations of ozone on the spores,colony expansion,hyphal morphology and cell membrane permeability of Fusarium graminearum and Fusarium oxysporum were studied to explore the pathogenesis of ozone.Ozone treatment can effectively inhibit the spore germination rate and sporulation of Fusarium graminearum,which is negatively correlated with ozone concentration.The lowest sporulation in the 135 mg/m3 ozone content treatment group was 32.69±1.33×10~7/dish,which was 27.56%of the control group.ozone treatment can significantly inhibit the expansion of colonies,to achieve the purpose of inhibiting their growth and reproduction;In the ozone treatment group,the dry weight of mycelia was lower,and the mycelia collapsed and tangled with each other abnormally,At the same time,ozone treatment led to the increase of cell membrane permeability of bacteria,the exudation of soluble sugar in cell contents,the imbalance of metabolism,and the failure of bacteria to grow normally or even death,among which,the liquid phase conductivity of bacteria and the soluble sugar content in mycelial exudate in the 135mg/m~3 treatment group were the highest.Therefore,ozone treatment can inhibit the bacteria colony expansion of Fusarium graminearum,and the 135 mg/m~3 treatment group has the strongest inhibitory effect on the pathogen.