Effect Of In Suit SiOx/LZM/TP-Chitosan Composite Preservation Coating On The Storage Quality Of Lateolabrax Japonicus Fillets And Its Antibacterial Mechanism

Based on the modification of in situ Si Ox,the chitosan preservation coatings were prepared by casting method with lysozyme(LZM)and tea polyphenol(TP)as additives.Meanwhile,the composite coatings were characterized by FT-IR,XRD and SEM,and their physicochemical properties were determined.The preservation properties of the coatings were studied with Lateolabrax Japonicus fillets as preservation objects.Choose Shewanella putrefaciens as the objects to reveal the action pathway and antibacterial mechanism of in suit Si Ox/LZM/TP-chitosan composite preservation coating.The effects of in suit Si Ox/LZM/TP-chitosan composite preservation coating on protein oxidation and muscle fiber structure of L.Japonicus fillet were studied.The research results indicate that:1.The microstructure characterization and physicochemical properties of in suit Si Ox/LZM/TP-chitosan composite preservation coating show that,the in situ Si Ox,LZM and TP makes the intermolecular force of the CS coatings strong,the structure compact,and then the microstructure and physicochemical properties of the coatings are improved.The preservation experiment results of in suit Si Ox/LZM/TP-chitosan composite preservation coating on L.Japonicus fillets show that,compared with untreated fish fillets,the coating treatment can effectively maintain the freshness of the fillets and inhibit the oxidation of protein and fat.The addition of in situ Si Ox,LZM and TP effectively inhibite the increase in the total number of colonies,p H,thiobarbituric acid(TBA)value,K value,and volatile basic nitrogen(TVB-N)value of fish fillets.The sensory score and texture index are slowed down,fat oxidation and protein breakdown are delayed,and significantly extended the shelf life of Lateolabrax Japonicus fillets by3-10 days.2.The bacteriostatic properties of in suit Si Ox/LZM/TP-chitosan composite preservation coating and its effects on the permeability and integrity of bacterial cell membrane,the activities of AKPase and ATPase were studied with Shewanella putrefaciens and as the antimicrobial objects.The results show that the addition of in situ Si Ox,LZM and TP improve the antibacterial performance of CS coatings,and the composite coatings more effectively destroy bacterial cell membranes,increase the integrity and permeability of cell membranes,thereby inhibite the growth and reproduction of bacteria.3.The effects of in suit Si Ox/LZM/TP-chitosan composite preservation coating on protein oxidation and muscle fiber structure of L.Japonicus fillets were studied.The results show that when in situ Si Ox is added into the CS coating film,its antioxidant effect is not enhanced,and there is no significant inhibitory effect on protein destruction in fish fillets.The addition of LZM and TP in the coatinginhibites the growth and reproduction of microorganisms in the fish fillets,and delayes the destruction of the proteins by the microorganisms and autolytic enzymes in the fish fillets,meanwhile,enhances the antioxidant activity of the fish fillets.Since LZM and TP have synergistic effects,the anti-oxidation property of in suit Si Ox/LZM/TP-chitosan compositis preservation coating is the optimal,and the anti-oxidation performance of L.Japonicus fillet muscle fibrin is further enhanced.