Preparation Of Nano Zinc Oxide/Amitrole Fresh Paper And Its Application In Mango Packaging

Mangoes breathe strongly and easily rotted after harvesting so the quality deteriorates.For further study to prevent the disease and extend preservation time,we use Nano-ZnO for antibacterial activity and Amitrole for ethylene adsorption to reduce the physiological activity.The research content as follows.Sodium dodecyl benzene sulfonate used as a dispersant and single factor test by changing the concentration of dispersant,pH and ultrasound time.The particle size and Zeta potential were used as test indicators.The results showed that the best dispersion effect was obtained when the dispersant concentration was 0.06%,the pH value was 11.5 and the ultrasonic time was 30 minute's.The result was optimized by orthogonal and the response surface method.The results showed that the dispersant concentration was 0.06%,the pH value was 11.35,and the ultrasonic time was 30.5 min.In the study of coating,we used calcium carbonate,titanium dioxide and kaolin to test the viscosity and solid content.The results showed that when the ratio of calcium carbonate to titanium dioxide was 4:1,the viscosity was 1423 mPa·s and the solid content was 53.99%.When the adhesive was 1.5%and the thickener was 0.4%,the workability was better,so as to determine the proportion of the coating formulation.Coated paper was prepared based on the coating formula and the physical properties of paper were investigated.The results showed that the burst resistance index was 2.12,the tensile strength was 19.87 kN,and the whiteness was 80.1%.The Nano-ZnO was sued as antiseptic and conduct antibacterial tests by changing the pH and the amount of coating.The results showed that when the pH of Nano-ZnO was 10.37,the antibacterial rate was the higher,and the larger the coating amount,the higher the antibacterial rate.So the pH was 10.37 and the coating amount was 10 g/m2.Amitrole(ATA)was used as single-factor test for adsorbents by gas chromatography analysis.Therefore,the best conditions of ATA adsorption ethylene:ATA concentration 30 mmoL · L-1,gas flow rate 2 mL · min-1,and temperature 20?.In order to further study the adsorption mechanism,Langmuir and Freundlich was performed an isotherm model fitting.The fitting correlation coefficients R2 were 0.9987 ? 0.9550.Therefore,ATA adsorption of ethylene is a process in which heterogeneous surfaces and monolayers coexist.The Nano-ZnO and ATA prepared to test the mangoes by setting three groups,including the fresh-keeping,base paper packaging and the fresh water treatment.Then mangoes were tested by hardness,weight loss rate and incidence,etc.The results showed that the hardness of the fresh-keeping paper group decreased slowly,which reduced the softening speed of the mango.The weight loss rate,incidence rate,and soluble solids of the fresh-keeping group were lower than the other two groups.The highest respiration rates were 108.2,120.4 and 129 mg CO2/Kg·h of the fresh-keeping group,the base paper parkaging group and the clean paper group.The preservation rate of vitamin C was 11.46%and 8.01%higher than base paper packaging group and the clean water group,so the coating has a good effect of preservation.