Preparation Of Antifogging And Antibacterial Modified Polyethylene Packaging Film And Its Application On Maintaining Quality Of Fresh Mushroom During The Storage

In a certain extent,the competition of fresh food market is decided by the scientific nature and feasibility of packing.Due to the change of external environment or metabolism of fruit and vegetale,the traditional fresh food packaging film can produce water vapor and fogging,which will reduce the transparency of film,accelerate the growth of microorganisms and cause the deterioration of fresh food.Antifogging and antibacterial packaging film can significantly improve the appearance quality of packaging products,maintain the packaging environmental humidity and inhibit the growth of microbial,thus to ensure the quality of fresh food and prolong its shelf life.In this study,the antifogging and antibacterial polyethylene packaging film was prepared based on the mechanism of fog formation and the bacterial propagation.The film can be produced to have antifogging and antimicrobial properties by adding antifoggants polyglycerol fatty acid ester(PGFE)and antifog masterbatch(YS),antimicrobial agents such as dehydroacetic acid sodium(DHA-S),calcium propionate(CP),and PE was served as the basement membrane.First use the different concentrations of PGFE to modified PE film and research the basic properties of the film.Second research the packaging properties of PGFE and YS modified PE film.Then,mix the mass fraction of 2%PGFE and 2%YS with different ratio of antibacterial DHA-S and CP to prepare antifogging and antimicrobial PE packaging film,and the basic properties of the film were investigated.Finally,use the modified antifogging and antibacterial PE packaging film to package the fresh mushroom at room temperature and observe the preservation effect.The study has the following conclusion,(1)The compatibility of antifog ingredients with packaging material has been solved.It was found that the addition of the dispersant improved the compatibility of the antifogging agents with the plastic substrate and determined that the amount of the dispersant was 0.5%.(2)Single antifogging agent on the performance of film was studied.Under the same condition of dispersant,the properties of PE packaging film modified with PGFE(0-3%)were investigated.Results showed that the hydrophilicity of the film improved and the contact angle decreased,the high temperature antifogging persistent period prolonged,the tensile strength decreased,the optical performance reduced,water vapor permeability increased and oxygen permeability decreased with the increase of PGFE.PGFE had good compatibility with PE film,and the film had a good heat resistance.Compared with PE film,2%PGFE modified PE antifogging film had a good antifogging performance and some packaging properties.(3)The species and contents of antifogging agents on the performance of film were studied.PGFE,YS had good compatibility with PE,and the content of 2%PGFE+3%YS were too high to cause agglomeration in the PE film,which had a greater influence on the mechanical properties of the film.With the addition of 2%PGFE+2%YS,the antifogging perfprmance of the film enhanced,high temperature antifogging persistent period prolonged,light transmittance decreased,haze increased,tensile strength and elongation at break reduced,the barrier properties to vapor and oxygen improved as well as thermal stability.Compared with PE film,the antifogging performance of the PE film was improved with the addition of PGFE and YS,and the film with 2%PGFE+2%YS had the best antifogging and packaging performances,can be used as a new food packaging material.(4)The combination of antifoggant and antibacterial on the film packaging performance was researched.The antifogging and antimicrobial PE packaging film was prepared with PE as raw material,PGFE and YS as antifoggants,DHA-S and CP as antibacterial agents.Results showed that the contact angle decreased,the high temperature antifogging persistent period prolonged,the antifogging and antimicrobial performances improved with the incorporation of PGFE and YS.Antifoggants and antibacterial agents could change the colour,decrease the light transmittance,elongation at break and the barrier properties to vapor and oxygen,increase the haze,tensile strength and thermal stability,and inhibit the Aspergillus niger and Monilia albicans.Because of the crosslinking and thermal decomposition,the membrane structure changed greatly.Compared with PE film,2%PGFE+2%YS+2%DHA-S+1%CP modified antifogging and antimicrobial PE packaging film had good antifogging and packaging performance,good antimicrobial effect on Aspergillus niger and Monilia albicans.Because of this,it can be used as a new packaging material for fresh food.(5)The film packaging effect of antifogging and antibacterial film was studied.The effect of the antifogging and antimicrobial PE packaging film on fresh mushroom during the storage at room temperature was investigated by analyzed the sensory evaluation,total viable counts,the change of weight loss rate,reducing sugars,Vc and MDA.Compared with PE film,sensory evaluation and all the freshness indicators reflected 2%PGFE+2%YS+2%DHA-S+1%CP modified antifogging and antimicrobial PE packaging film had better preservation effect on mushroom,which could extend the shelf life of mushroom to 2-4 days at room temperature.Antifogging and antimicrobial PE packaging film could significantly inhibit the growth of microorganisms,the rise of weightlessness rate and the increase of MDA,postpone the decline trend of reducing sugars and Vc and had good antibacterial effect.(6)Caused by antifoggant and antibacterial materials,the optics and mechanics performance problems still need further study.