Study On Preparation And Properties Of Antibacterial Film Composed Of Fish Gelatin, Chitosan&Nano-ZnO

As the increasing awareness of environmental protection, chemical synthetic plasticscouldn’t satisfy the needs of food packaging. Therefore, edible package made bynatural biological material is becoming focus of study in the field of package. With theenhancement of life quality, consumers require more and more on food quality.Microorganism is an important factor causing spoilage of foods, and shelf life of foodwould be prolonged by antimicrobial package which could inhibit the remainingmicroorganisms in the food surface. In this paper, the edible composite film was made ofthe fish gelatin and chitosan followed by addition of nano-ZnO in differentconcentrations, which could be used to improve the mechanical properties and increasethe antimicrobial activity. The main contents of the research were listed as follows:(1) Composite film solution and its properties. The gel strength of composite filmsolution improved significantly after nano-ZnO was added. The gel strength achieved20.906gf/mm2which was324%higher than that of control when the concentration ofnano-ZnO reached0.6%, but no improvement of viscoelasticity was observed.Additionally, the storage modulus (G′) and loss modulus (G″) improved slightly. Theantibacterial effect of composite film liquid enhanced as the addition of nano-ZnOincreased. The antibacterial effect was significant when the concentration of nano-ZnOwas0.6%.(2) Properties test of the composite films. The mechanical property, watervapor permeability and impedance properties of the composite film were changedremarkably after nano-ZnO was added. The mechanical properties of the compositefilm became bad as the concentration of nano-ZnO grew, which showed more fragileand easily to be broken. The tensile strength (TS) and elongation at break (EB)dropped to16.06MPa and5.75%respectively, which was33.2%and82.1%less thanthe control. However, the impedance property was improved and the water vapor permeability, water solubility and UV transmittance decreased significantly when thenano-ZnO was incorporated.(3) Structural characterization of the composite films. The FTIR spectra revealedamide-I, amide-II and amide-III peaks of the films shifted to lower wavenumbers. TheX-ray diffraction indicated that nano-ZnO produced a small effect to its structure,nevertheless it didn’t destroy the compatibility and crystal structure of gelatin andchitosan. SEM results showed that the microscopic structure of the films arrangedcompactly. The dispersed particle was observed on the surface of the films withnano-ZnO, which illustrated that gelatin, chitosan and nano-ZnO were mixed well toform a complicated system.(4) Antibacterial effect and application of the composite films. The films possessedantibacterial activity on four different bacteria with dose dependent of nano-ZnO.When compared with the control, the antibacterial effects of composite films with0.6%of nano-ZnO on L.monocytohenes and Staphyloccocus aureus were15%and108%enhancement. The composite films can effectively inhibit the propagation ofbacteria and reduce the TVB-N compared with common PVC cling films when theywere applied to preserve aristichthys nobilis.