Research On Properties And Release Law Of Cinnamaldehyde Biodegradable Antibacterial Active Packaging Film

The environmental pollution problems caused by the large-scale use of petroleum-based plastics and people's requirements for higher food quality,the use of biodegradable materials to develop a controlled-release active food packaging has aroused widespread attention of researchers.In this study,biodegradable antibacterial food packaging with controlled release effect was prepared using biodegradable materials(polylactic acid,chitosan and sodium alginate),cinnamaldehyde and nano controlled release materials(carbon nanotubes,nano montmorillonite and halloysite nanotubes)as raw materials.The effects of the addition of controlled release nanomaterials on the physical and chemical properties of food packaging film were studied.The function of nano controlled release materials in the release experiment was analyzed.The antimicrobial activity of the controlled release food package was also evaluated.(1)The cinnamaldehyde(CIN)was loaded by carbon nanotubes(CNTs),and then added to the solution of polylactic acid(PLA)and polycaprolactone to prepare a PLA-based controlled-release antibacterial composite film.The changes of the physicochemical properties of the PLA/CNTs/CIN film were studied,and the release of CIN in the composite film was investigated under the environmental storage environment.The results showed that CIN was loaded with CNTs and then added to the PLA matrix had no significant effect on the barrier properties of the composite film,but could significantly improve the UV resistance and elongation at break of the composite film,and reduced the glass transition temperature of the film.The PLA/CNTs/CIN film could be extended for 7 days under the controlled release of CNTs,and the antibacterial activity of the composite film against Staphylococcus aureus and Escherichia coli could be extended for up to 7 days.(2)The montmorillonite(MMT)was acidified and modified by hydrochloric acid,and then the CIN was loaded by acid-modified MMT(acid-MMT)to obtain CIN-loaded MMT(acid-MMT-CIN).Finally,the acid-MMT-CIN nanoparticles were used as fillers to prepare the controlled release antibacterial composite film with chitosan as raw material.The effect of acid-MMT loaded with CIN on the antibacterial and antibacterial activity of the physicochemical properties of the composite film was studied,and the release behavior of CIN in the composite film in a fatty food simulant was investigated.The characterization of the nanoparticles showed that the MMT was successfully acidified and the CIN was successfully loaded on the acid-MMT.The acid-MMT loaded with CIN in the composite film had good compatibility with the substrate and was evenly distributed,which improved the water vapor barrier ability,rigidity,and extensibility of the composite film.Moreover,the UV resistance of the composite film was significantly improved,but the opacity of the composite film was also increased to a certain extent.The release time of the CS/acid-MMT-CIN film with acid-MMT was 72 h longer than that of the film without acid-MMT,and the CS/acid-MMT-CIN film showed significant antimicrobial activity against both Staphylococcus aureus and Escherichia coli.(3)The halloysite nanotubes(HNTs)was etched with sulfuric acid,and then the etched HNTs(T-HNTs)was used as a carrier of CIN to prepare CIN-loaded nanoparticles,and sodium alginate(SA)was used as a matrix to develop a controlled-release antibacterial composite film.The effects of CIN-loaded nanoparticles on the physical functional properties and antibacterial activity of the composite film were systematically evaluated,and the release of CIN in the film was also quantified.The characterization of the nanoparticles indicated that the HNTs were successfully etched and loaded with CIN.The incorporation of CIN-loaded nanoparticles improved the water vapor barrier and tensile strength of the composite film,while also greatly reducing the negative effects of ultraviolet rays.Through the release experiment in fatty food simulants,it was confirmed that SA/CIN film prolonged the release of CIN due to the controlled release effect of T-HNTs,which was 144 hours longer than that of SA/CIN film.Finally,the obvious antibacterial activity of sodium alginate/cinnamaldehyde film was also verified by the antibacterial experiment(Staphylococcus aureus and Escherichia coli).