Research Of Nano SiO₂,TiO₂ Modified Crosslinked PVA-based Film Material And Its Influence On Fresh Preservation Effect Of Low-salted Duck Eggs

Salted duck egg is one of the popular consumer favorite traditional food in our country,it's need to be packaged to extend shelf storage period after the cylinder.Currently the vacuum packaging process is generally used in traditional salted duck egg.The process quality is not stable,high cost,large energy consumption,and it damages to the environment,and the long time high temperature sterilization could reduce the quality of the products.Traditional salted duck egg protein salt up to 6-7 g/100 g protein,its flavor quality is poor,and don't conform to the modern food consumption concept of low salt and healthy.Therefore reducing the protein salt of salted duck egg,using biodegradable modified PVA coatingsalted duck eggs to change the traditional vacuum packaging and improve eggs'quality,extend the shelf life,thatis of important significance to realize the traditional salted duck egg production to high efficiency and energy saving,low carbon emissions,green health is of great significance to the modern automated production mode transformation.In order to improve moisture barrier performance of the polyvinyl alcohol?PVA?based composite packaging material,and improve the quality and flavor of traditional salt duck eggs,on the basis of early research team,borax and nano SiO₂,TiO₂were used to crosslinking modified PVA,and the crosslinked PVA nanocomposite coating material was applied to low-salted duck eggs with regulation of salt of dynamic salting to research its preservation effect.The concrete content includes the following three aspects:1.Research ofnano SiO₂,TiO₂ modified crosslinked PVA-based film materialWithwater vapor permeability?Pv?as response value,response surface method was used to research theeffects of borax accompanied nano SiO₂,TiO₂ crosslinked modified PVA-based film material on Pv.Structural characterizationwas done on optimized PVA composite membrane,and water resistancewas measured.The result shows that Borax accompanied nano SiO₂,TiO₂ crosslinked modified PVA-based film material can significantly reduce?p<0.05?its Pv,and that Borax and nano SiO₂ or TiO₂ hada certaininteraction?p<0.05?on Pv.Used the lowest Pv as response values to optimize the film-forming process conditions,and the optimal conditions were that nano SiO₂ dosage was 0.033g/100mL,nanoTiO₂ was 0.042g/100mL,and Borax was 0.032g/100mL,under these conditions,Pv was 9.729±0.074mg/?m·d·kPa?,lower than the PVA film 44.68%.The antibacterial of the optimization of PVA-based composite film was improved,and the total number of E.coli colonies was reduced by 1 order of magnitude.Structural characterization and water resistance test showed that borax collaborating modified nano-SiO₂,TiO₂ could change the molecular structure of PVA,reducing permeability coefficient,and moisture absorption and swelling ratioof PVA.2.Research on regulation ofsalt of low-salt duck eggsd ynamic curingUsing the process of pre-cured by ultrasonic synergy bubbles-high salt bubbling preserved-low salt bubbling to cure salted duck eggs.Salt and sensory evaluation were used as indicators of orthogonal experiment.We research the impact ofdesalination timing,amount of low-salt solution and desalination time on product quality and determine the optimum process parameters,and make performance measurement and sensory evaluation on salted duck eggs which are salted by optimizing process.The results show that:three factors significantly affect the product quality,andthree factors have different levels of influence.Desalting after salting for 28d,desalting for 8 daysand salt addition amount of low-salt pickle liquid was 2g/100mLH2O.dependent on comprehensive optimization process.saltcontent of egg protein and egg yolk of salted duck egg produced by this processwere 3.67±0.11g/100g andl.16±0.08g/100g,and sensory score was 95.12±1.13.Salt content of egg proteinsignificantly reduced by 44.2%?p<0.05?comparing to the control group,and oil content of yolk increases,and organoleptic qualityimproved.3.Research on effect of PVA-based nanocomposite coating material on low-salte duck eggs preservationPVA-based nano-SiO₂,TiO₂ composite film,PVA-liquid paraffin composite film,and PVA single filmwerecoated on boiled low-salte duck eggs.Coated duck eggs are stored at room temperature for 90d,and their physical and chemical indicatorsand sensory evaluationwere measured.The results show that the composite film can be uniformly covered on the surface of the shell,and closes pores.Preservation effect of PVA-based nano-SiO₂,TiO₂ composite film is better than other groups and its weight loss after being in storage for 90d is only 9.11%.pH value ofegg yolk and egg protein changed respectively from 7.28 to 7.34,and 6.16 to 6.36,and colonies total of egg protein and egg yolk?324,421 CFU/g?was significantly lower than colonies total ofeggs coated by PVA single film?826,1220 CFU/g?,and sensory evaluation results were also satisfactory.These results indicate that PVA-based nanocomposite coating film materials can effectively preventmoisture loss of low-salted duck eggs,delaythe change of pH,inhibit the growth of microorganisms,and have good preservation effect after being in storage for 90d.