Synthetise Of Composite Packaging Material Based On Nano-α-Fe₂O₃ Modify Polyvinyl Alcohol And Effect On Preservation Of Clean Eggs

Nowadays,the frequent occurrence of avian influenza,clean egg has become a major circulation products.The method of egg coating preservation is simple,fresh,easy to automate production,labor savings,and low production costs,to attract a lot of attention of scholars at home and abroad and has made some research achievements.Coating will extend clean eggs’ shelf life and quality of clean eggs,and is the key of the Green package technology.Therefor,it is ground-breaking significance for clean eggs overall circulation in the domestic market.Due to excellent film-forming performance and biodegradable characteristics,polyvinyl alcohol are widely used in food packaging field.However,because its molecular structure rich in hydroxyl group and when environmental relative humidity is higher,its barrier properties decreased significantly,affecting its applications in food fresh-keeping packaging.Nano-α-Fe₂O₃ has antibacterial activity under visible light photocatalytic,inhibits the growth and reproduction of pathogenic bacteria.Corn oil is hydrophobic material,if coating on the surface of foods could effectively block moisture from entering or evaporate.This project intends to use corn oil and Nano-α-Fe₂O₃ to modify polyvinyl alcohol.At the same time,compares process performances with several nano-functional modification of polyvinyl alcohol composite films early studied by our research group,and then compares the effect of keeping clean eggs fresh.The details are as follows:1.Synthetise of composite packaging material based on nano-α-Fe₂O₃ modify polyvinyl alcoholFirst determine the emulsion HLB value and mixing emulsifying agent dosage,then single-factor experiment exploring how does Nano-α-Fe₂O₃ and corn oil affect moisture permeability and resistance to water of polyvinyl alcohol film.Design response surface experiments by Design-Expert8.0.6,and take film permeability and moisture absorption rate as the objective function,nano-α-Fe₂O₃ and corn oil content as a variable factor,using the quadratic regression model to study interactions on polyvinyl alcohol composite membrane between Nano-α-Fe₂O₃ and com oil.At the same time,optimizing the ratio between the raw material.Study results show that the content of α-Fe₂O₃ and corn oil significantly affects permeability and moisture absorption rate of polyvinyl alcohol and there is a clear interaction between them.Quadratic regression model optimization of best recipe for corn oil 15g/L,Nano-α-Fe₂O₃ 0.50g/L,mixing emulsifying agent 6.00g/L.minimum film-forming permeability rate is 21.42（g/m2.d）,minimum moisture absorption rate is 5.01%.The results were lower 89.40%,82.67%than those in the control group.2.Effect of composite packaging material based on nano-a-Fe₂O₃ modify polyvinyl alcohol on preservation of clean eggsFor compared effect of several composite materials on preservation of clean eggs,the research coated dipping clean eggs for two times with Nano-SiO2-TiO2 and liquid Paraffin modified polyvinyl alcohol composite material（A group）,Nano-α-Fe₂O₃ and beeswax modified polyvinyl alcohol composite material（B group）,nano-Fe3+/TiO2 and Lac modified Polyvinyl Alcohol material（C group）and Nano-α-Fe₂O₃ and Com oil modified polyvinyl alcohol composite materiaI（D group）in different group,then dried films.Not coated film processing for control group（CK group）,In constant 25℃ tem perature and 75%relative humidity conditions,detecting egg weight loss and physical indicators and chemical indicators.Results showed that:under temperature 25℃ and 75%relative humidity conditions,eggs storage period of each group respectively for:CK group is 35 days,A group is 49 days,C group is 63 days,B group and D group are greater than 70 days.Compared with control group,coating can be effectively keep the egg quality.Store up 70 days,the egg fresh rate ofB group was 100%,the best group,to keep egg quality longer 35 days than CK group.Analysis and compared the cost of each group respectively for:A group is 0.006 Yuan/Gold,B group is 0.012 Yuan/Gold,C group is 0.023 Yuan/Gold,D group is 0.0197 Yuan/Gold.Considering integrated the film’s effects and cost,Nano-α-Fe₂O₃ and Corn oil modified polyvinyl alcohol composite material is the most economic and efficient.