| Protein-based Pickering emulsion is an emulsion that uses a safe,non-toxic,biocompatible protein macromolecular particle to stabilize the oil-water interface.It not only has the functional properties of traditional emulsion,but also has high stability,controllable particle size distribution and low toxicity.With and without surfactants,it can be widely used in biomedicine,food and other fields.There are many factors affecting the stability and function of protein-based Pickering emulsion,but the stability of protein particles is one of the most important factors,but the protein is prone to denaturation and aggregation under acid-heat conditions,which limits its stability in Pickering emulsion.Application in sex and Pickering emulsion delivery drug systems.In order to construct a protein-based Pickering emulsion with high stability and wide application,the glycosylation reaction established in the early stage of the laboratory can effectively improve the functional properties of the protein,and the whey protein isolate is covalently combined with lactose.The acidheat stable glycosylation reaction product,and using the epigallocatechin gallatebinding protein to regulate the degree of aggregation of the protein,the preparation of a particle size-controlled glycosylated protein-polyphenol nanocomposite to construct a Pickering emulsion delivery system,the natural hydrophobic active ingredient is embedded and its stability in vitro is evaluated.The main work of this thesis is as follows:1.The glycosylated protein-polyphenol nanoparticle of a suitable size is prepared.The binding of the complex was characterized by polyacrylamide gel electrophoresis(SDS-PAGE),Fourier transform infrared spectroscopy and endogenous fluorescence spectroscopy.The binding mode of the protein to EGCG was determined,and the protein and EGCG were optimized by particle size potential analysis.The ratio of binding to the pH environment of the solution showed that the glycosylation reaction product was combined with EGCG by hydrogen bonding and hydrophobic interaction.The optimal binding ratio was protein: EGCG was 1:1(w/w),and the solution pH was 3.0.The glycosylated protein-polyphenol nanoparticles with a particle size of about 110 nm were prepared,and the nanoparticles prepared under the optimal conditions were characterized by atomic force microscopy.2.Preparation and stability analysis of Pickering emulsion.The microscopic and microscopic characterization of Pickering emulsion prepared by different oil phase mass fractions by optical microscopy and fluorescence confocal microscopy showed that we successfully prepared Pickering emulsion.The storage stability and thermal stability analysis of the prepared Pickering emulsion showed that the glycosylated protein-EGCG nanoparticle-stabilized Pickering emulsion has good stability and can effectively inhibit the flocculation and precipitation of the emulsion.3.The optimal emulsion conditions were used to embed curcumin and ?-carotene respectively to investigate the stability of the emulsion embedded in the two active substances and the stability and retention of the active substances in the emulsion in different in vitro simulated environments.The results show that Pickering stabilized by glycosylated protein-polyphenol nanoparticles has a good protective effect on curcumin and carotene,and significantly improves its stability.In vitro simulated gastric juice environmental digestion experiments show that the emulsion can be stable in harsh environments such as gastric juice.By simulating the digestion of Pickering emulsion in intestinal juice,it was found that the glycosylated proteinpolyphenol nanoparticles stabilized emulsions with the slowest digestion and the highest retention rate of active substances.In summary,we constructed a Pickering emulsion delivery system that simultaneously loaded the pro-/hydrophobic natural active ingredient.The Pickering emulsion constructed by glycosylated protein-EGCG nanoparticles can improve the fat solubility of curcumin and ?-carotene.Stability and retention of the active ingredient.It provides some theoretical basis for the application of natural active substances in emulsion delivery systems,in order to broaden the application of protein-based Pickering emulsion systems in the food industry. |
PDF Full Text Request