Preparation Of PH-responsive Core-shell Structure Antibacterial Fiber Mat And Application Of Fresh-keeping Mutton In Fresh-keeping Mutton

The nutrients and water are rich on the surface of chilled-fresh mutton,which is the natural medium for the growth and reproduction of microorganisms.Therefore,chilled-fresh mutton is easy to be contaminated by microorganisms.The freshness degree is secondary fresh meat when the pH value of fresh mutton is greater than 5.7,which is easy to breed microorganisms and leads to the decline of quality indexes of fresh mutton,it is one of the reasons for the shortened shelf life.Hence,how to extend the shelf life of chilled fresh mutton while sensing the quality change of chilled fresh mutton is the current challenge.In our work,a kind of fiber pad with slow release bacteriostatic agent that can sense and respond to surface pH quality signal of chilled fresh mutton was prepared by electrostatic spinning technology,which was applied to tray packaging of chilled fresh mutton.Ph-sensitive material Eudragit L100-55 and natural bacteriostatic agent(tea polyphenols)were used as core layer mixture materials and biodegradable material(polylactic acid)was used as shell material to prepare fiber pads with natural bacteriostatic agent and environmentally sensitive pH response.The structure,surface morphology change,pH response and antibacterial properties of the fiber cushion were tested,and the effect of the fiber cushion on the pallet packaging and storage quality of chilled fresh mutton were evaluated.The research results are as follows:Firstly,the study on the structure and surface morphology of the fiber pad by ftir,surface morphology and wettability test showed that the fiber pad with core-shell structure was successfully prepared;the analysis of different pH response of fiber pad showed that the uniaxial fiber pad is fully inflated after 3h when pH>6,while coaxial fiber pad passes 24h,the dyeing agent is released slowly while maintaining the original morphology,indicating that coaxial fiber pad has the effect of slowly releasing dyeing agent.Secondly,the research and analysis of diffusion test of fiber pad show that:the purply-brown diffusion ring of tea polyphenols is obvious at 30min for uniaxial fiber pad.Compared with uniaxial fiber pad,the purply-brown diffusion ring of tea polyphenols is obvious for coaxial fiber pad at 1.3h later.The test shows that coaxial fiber pad has the effect of slowly diffusing tea polyphenols.Analysis of antibacterial performance of coaxial and uniaxial fiber pads showed that the antibacterial rate of coaxial and coaxial fiber pads against escherichia coli and staphylococcus aureus were 90.0%.Finally,the analysis of the preservation behavior of different types of fiber pads in chilled meat shows that the pH value of chilled mutton is always greater than 5.5,and the pH-responsive polymer EL100-55 keeps swelling,resulting the tea polyphenols was continuously released and the growth of microorganisms was inhibited.Compared with blank chilled mutton,the shelf life of uniaxial and coaxial fiber pads was extended to 9d and 12d,respectively.