| In recent years,Pickering emulsions have a wide range of applications in the encapsulation and controlled release of bioactive substances,antioxidants,partially hydrogenated oils replacement,and modulation of food texture.Chitosan,as the only cationic polysaccharide,has biocompatibility and wide applicability.However,its high hydrophilicity leads to low surface activity and poor emulsification.Therefore,improving the emulsification and hydrophobicity of chitosan is of great significance for its practical application.Introducing small molecular active substances into the chitosan base can improve its physicochemical properties.Based on the Pickering emulsion’s oil-water biphase characteristic,adding cinnamaldehyde to the oil phase can react with chitosan to reduce its surface active molecules,thereby improving its emulsification properties.Therefore,using chitosan as the raw material,a composite particle with arabic gum(GA)was formed,and different types of cinnamaldehydes were introduced to construct a stable Pickering emulsion system.At the same time,bioactive substances were embedded and released,and fresh strawberries were used as the research object to further explore the application of curcumin-loaded Pickering emulsion active coating in fruit preservation,providing theoretical basis for the practical application of Pickering emulsions.The main results of this study are as follows:(1)Four different types of cinnamaldehydes’ effects on the water-oil interface of chitosanbased Pickering emulsions were investigated.After chitosan and cinnamaldehydes underwent Schiff base reaction,the stability of the emulsion was improved.Microscopic and particle size results showed that adding cinnamaldehyde can significantly reduce the Pickering emulsion’s particle size,from 32.54 μm to 12.40 μm.The addition of different cinnamaldehydes can reduce the interfacial tension,but due to the cinnamaldehydes’ different hydrophobicity,the degree of interfacial tension reduction is different.Cinnamaldehyde with low water solubility,such as cinnamaldehyde and decanal,reduced interfacial tension by 3.64 mN/m and 2.80 mN/m,respectively,to form a stable interfacial film to achieve the purpose of stabilizing the emulsion.(2)Based on the cinnamaldehyde-stabilized chitosan-based Pickering emulsion,curcumin was embedded to explore the loading situation of curcumin in different concentrations of cinnamaldehyde/CS/GA Pickering emulsion system.From the microscopic and particle size results,it can be seen that the addition of curcumin can increase the emulsion’s particle size,but does not affect the emulsion’s water-oil balance.The emulsion’s curcumin loading rate can reach up to 95.43%,and the DPPH free radical scavenging rate and ABTS scavenging rate can reach up to 70%.In the 95%ethanol simulated liquid,the curcumin powder’s release rate quickly reached 100%,but the curcumin embedded in the cinnamaldehyde/chitosan/arabic gum particle-stabilized Pickering emulsion released slowly in the system.After 60 hours,the curcumin release rate was 85%.These results prove that the cinnamaldehyde/chitosan/arabic gum particle-stabilized Pickering emulsion system can serve as an effective bioactive substance delivery system.(3)A study was conducted by mixing curcumin-loaded Pickering emulsion with chitosan solution to form an edible coating solution,and investigating the effects of adding different concentrations of the emulsion on the preservation performance of strawberries.The results showed that the coating treatment effectively reduced the weight loss and decay rate of strawberries during an 8-day storage period,and maintained good changes in physicochemical indicators.Strawberries treated with 10%emulsion coating only showed a decrease of 5.43%in soluble solids,while reducing the enzyme activity of polyphenol oxidase.It had a good inhibitory effect on both bacteria and fungi,effectively prolonging the storage period of strawberries and reducing the loss of nutrients in strawberries. |
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