Preparation And Properties Of Chitosan Preservation Coating Modified With The Nano SiO_x Synthesized By In-situ

In this paper, the nano SiOx/chitosan compound preservation coating was prepared byin-situ synthesis method. The gas permeabilities, mechanical properties, freshness storageproperties to the sciaenops ocellatus of the preservation coating were studied. And thecoatings were characterised by XRD、FT-IR、SEM、TEM. Besides, titanium doped zinc oxidepowder was prepared by solvothermal, and the antibacterial performance, antibacterialmechanism of it were studied. After that, titanium doped zinc oxide powder was added in thenano SiOx/chitosan coating liquid, and the nano Ti/ZnO/SiOx/chitosan compoundpreservation coating was prepared. In the same way, the gas permeabilities, mechanicalproperties, microstructure, freshness storage properties to the sciaenops ocellatus of thepreservation coating were studied. The specific research content as follows:1. The nano SiOx/chitosan compound preservation coating was prepared by in-situsynthesis method. The results prove that: with the increase of SiOx adding amount, the gaspermeabilities of the coating was decreased firstly and increased subsequently. When theSiOx adding amount was0.03%, carbon dioxide permeabilities of the coating reached thelowest value. When the SiOx adding amount was0.05%, water vapor permeabilities andoxygen permeabilityies of the coating reached the lowest value. With the increase of SiOxadding amount, tensile strength and breaking elongation were increased. When the SiOxadding amount was0.03%, the mechanical properties of the coating were optimum. When theSiOx adding amount continued to increase, the mechanical properties declined. The chitosanliquid and nano SiOx/chitosan liquid were painted on the sciaenops ocellatus respectively,air-dried. And the untreated sciaenops ocellatus were used as control. All of the sciaenopsocellatus were stored at4℃. Compared with the control group, coating can effectivelymaintain the red fish freshness, delay the pH, TBA, TVB-N, K values and texture changes,induce the growth of the total bacteria. The preservation of the SiOx/chitosan compoundpreservation coating was better than the pure chitosan coating.2. The nano SiOx/chitosan compound preservation coatings were prepared by in-situsynthesis method with different chitosan concentrations. The results show that: with the increase of chitosan concentration, water vapor permeabilities, carbon dioxide permeabilities,oxygen permeabilityies and breaking elongation of the coating were decrease, and the tensilestrength was enhanced. The sciaenops ocellatus were treated by different concentrationchitosan and stored at4℃. Compared with the control group and other concentrationchitosan coatings, the coating with1.5%chitosan concentration can maintain the red fishfreshness, delay the pH, TBA, TVB-N, K values and texture changes, and reduce the growthof the total bacteria more effectively.3. The nano SiOx/chitosan compound preservation coatings were prepared by in-situsynthesis method with different glycerol concentrations. The results show that: with theincrease of glycerol concentration, gas permeabilities and breaking elongation of the nanoSiOx/chitosan coating were increased, and the tensile strength was reduced. The sciaenopsocellatus were treated by SiOx/chitosan coating liquid with different glycerol concentrationsand stored at4℃. The test results of biochemical indexes andsensory evaluation indicatethat the influence of glycerol on the preservation was not obvious.4. The titanium doped ZnO powders were modified, and then the powders were added tothe nano SiOx/chitosan coating liquid. The Ti/ZnO/SiOx/chitosan coating was prepared. Theresults prove that: with the increase of Ti/ZnO adding amount, the gas permeabilities of thecoating was decreased firstly and increased subsequently, and the mechanical properties wereenhanced. Compared with the SiOx/chitosan coating, the preservation effect ofTi/ZnO/SiOx/chitosan coating was improved.