| A new type of active packaging materials named antibacterial film is developing rapidly inrecent years, it adds a certain amount of antibacterial agent in the film packaging material,making which antimicrobial to reduce or inhibit microbial growth in food and packaging toextend the shelf life of food. Antibacterial film not only plays a role in food safety, convenienttransportation, and storage, but also has opened up a new field of food packaging, therefore itsapplication has broad space for development. Compared with the developed countries, ourcountry’s antibacterial film research is still in the early stage of development. With our country’semphasis on food safety and the advantages of antibacterial membrane potential quality andsafety, the antibacterial membrane demand will increase year by year and the requirement of theperformance will be higher, so to speed up the study of antibacterial film has the vitalsignificance. This thesis uses cinnamic aldehyde as antibacterial agent, biological absorption anddecomposition of polylactic acid (PLA) as the backing material, to prepare cinnamicaldehyde/PLA nanofibers antibacterial film with the electrostatic spinning technique, and tostudy its preparation technology conditions, structure, performance, and application.Firstly, using the saturated aqueous solution method to prepare the cinnamicaldehyde/β-cyclodextrin inclusion complexes, using single factor experiment and orthogonalexperiment to ascertain the inclusion process parameters. The optimum process conditions forthe inclusion complex with inclusion rate of89.25%was that the process conditions forβ-CD/cinnamaldehyde feeding ratio should be1/0.1(g/mL), stir for1h with mixing temperature45℃.Secondly, the cinnamic aldehyde/β-CD inclusion compound with the mass fraction of1%,3%, and5%were added to the PLA in the solution, respectively. The cinnamaldehyde/PLAnanofiber antimicrobial membrane was prepared under the process condition that theenvironment temperature is20~22℃and relative humidity is40%~50%, the volume of mixedsolvent of acetone comparing to that of DMF(V/V) is1:1, PLA mass fraction is10%, spinningvoltage is18kV, with receiving distance17cm. The morphology of the nanofiber membranewere investigated by scanning electron microscope. At the same time, the functional groups ofthe cinnamaldehyde/PLA nanofiber antimicrobial membrane were analyzed via infra-redspectrum. Their thermodynamic properties, mechanical properties, water contact angle, andantimicrobial properties were studied. The results showed that the morphology ofcinnamaldehyde/PLA nanofiber antimicrobial membrane is fine. Its diameter is in the range from133to177nm. The IR spectrum shows the interaction between cinnamic aldehyde andPLA was physical blend. With the increasing of inclusion compound, the TG, water contactangle, and breaking strength of the antimicrobial membrane were decreased, however, thevitrification transformation temperature of the antimicrobial membrane changed slightly. Theantimicrobial membrane is antibacterial to Escherichia coli, Staphylococcus aureus, andBacillus subtilis, and its antibiosis was strongest to Staphylococcus aureus.Finally, fresh pork was placed in low temperature (4℃) after storage with cinnamaldehyde/PLA nanofiber antibacterial membrane. The results showed that in the process of preservationof chilled fresh pork, the every index of chilled fresh pork which stored with thePLA/cinnamaldehyde nanofiber antimicrobial membrane is superior to the control membrane,the effect is better along with the increasing of the content of antibacterial. When the massfraction of antibacterial is5%, the child pork can keep index of fresh meat during12d time,which was6d longer than the control group. |
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