Preparation And Application Of Gelatin-chitosan Nanocomposites Based On Panxian Ham

Panxian ham is a traditional fermented meat product.Its production and fermentation and maturation process are all carried out under natural conditions.During the fermentation and maturation process,there are problems such as high lipid peroxidation and serious microbial growth.There have been studies using lard and starch as base materials,and vegetable essential oils as antibacterial and antioxidant coatings to inhibit ham lipid peroxidation and microbial growth.It has certain effects.However,coatings based on animal oil or vegetable oil are effective.The layer itself has lipid oxidation reaction,which requires repeated coating treatment,which is laborintensive.In this experiment,the preparation of gelatin-chitosan essential oil nanocomposite materials was carried out.Gelatin-chitosan was used as the base material to embed cinnamon essential oil to explore its antibacterial and antioxidant effects.Membrane treatment,to investigate the effect of reducing ham lipid peroxidation and microbial growth,in order to provide theoretical basis and technical support for antibacterial and antioxidation of ham modern technology.(1)In this study,gelatin and chitosan were used as the film-forming matrix,and glycerol was used as the plasticizer to prepare the gelatin/chitosan/cinnamon essential oil nanocomposite by the self-assembly method.The embedding rate is an index.On the basis of single factor experiment,orthogonal experiment method is used to determine the best ratio of composite materials.The optimal process is as follows:chitosan concentration is 3 mg/m L,gelatin concentration is 6 mg/m L,cinnamon leaf essential oil concentration is 3 mg/m L,emulsifier concentration is 3 mg/m L,and the p H of the solution is adjusted to 4.5.The speed is 800 r/min,the stirring time is 30 min,the glycerin content is 20%,and the TPP concentration is 1 mg/m L.(2)The gelatin/chitosan/cinnamon essential oil nano film was prepared by the solution casting method to characterize its mechanical properties,structural properties,hydrophilicity and antibacterial and antioxidant properties.The results showed that the tensile strength(TS)and elastic modulus(EM)of the film containing cinnamon essential oil were lower than that of the gelatin/chitosan film,and the elongation at break(EAB)did not change significantly;the structure of the film was characterized by XRD and FTIR,and it was concluded that the cinnamon essential oil,gelatin and chitosan molecules were connected to each other through hydrogen bonds,and the different components had good interaction and compatibility;the morphological study of the film by SEM and AFM revealed that cinnamon essential oil is beneficial to the appearance of obvious pores on the surface of the film,which increases the water vapor transmission rate and hydrophilicity of the film;the inhibition zone test and the DPPH radical scavenging rate effect Tests have shown that the incorporation of cinnamon essential oil can significantly improve the antibacterial and antioxidant properties of the composite.(3)The experimental results of nano-composite coating on the surface of Panxian ham show that: The gelatin/chitosan/cinnamon essential oil coating can slow down the lipid oxidation on the surface of the ham,protect the color of the ham,reduce the total number of bacterial colonies on the surface of the ham,and inhibit the growth of harmful bacteria.(4)Based on the detection and analysis of the GC-MS method,it reflects the changes in the composition of the volatile flavor compounds of Panxian ham by the coating treatment.The results showed that the coating treatment resulted in the increase of 13 flavors in ham,namely myristaldehyde,trans-cinnamaldehyde,cinnamaldehyde,valeraldehyde,7-octene-4-ol,ethanol,methyl mercaptan,4-benzene 2-butanol,nheptacontane,dodecane,isovaleric acid,2-heptanone and 3-octanone.The coating treatment has no significant effect on the types,quantity and relative content of ham flavor substances.It was found that the ham coating treatment promoted the reduction of relative content of flavor substances related to lipid peroxidation such as hexanal.