Stabilization Of W/O/W Double Emulsion With Lecithin Modified Kaolinite As Emulsifier And Synergistic Loading Effect On Curcumin And Catechin

Curcumin is a natural antioxidant dye that has a wide spectrum of biological activities.As a natural additive,curcumin has been received widespread attention in food industry.Catechin is an important component of tea,and it has many functions such as prevention and treatment of cardiovascular diseases and cancer prevention.Studies have shown that the combination of curcumin and catechin has a synergistic effect of disease prevention and health.However,catechin is an water-soluble drug and curcumin is an oil-soluble drug,resulting in a serious kinetic mismatch between the two drugs.In this article,lecithin-modified kaolinite was used as an emulsion stabilizer to prepare oil-in-water?O/W?emulsion and double?W/O/W?emulsion.The synergistic encapsulation effect of emulsion on curcumin and catechin was studied.The following results were obtained:1)Kaolinite was selectively modified with lecithin as a modifier by Pickering emulsion method.The PC molecule was successfully grafted onto the octahedron surface of the kaolinite owing to the hydrogen bonded between choline group?-CH₂CH₂N⁺?CH₃?₃?of PC and the hydroxyl groups on the kaolinite octahedron surface,thereby expanding the Janus characteristics and obtaining kaolinite with different modification degrees.2)Encapsulation of curcumin with Pickering emulsion stabilized by lecithin-modified kaolinite.There was 81.12%curcumin retained after 120 min storage in simulated gastric digestion,while curcumin was totally released after 150min storage in simulated intestinal digestion.The bioavailability of curcumin encapsulated by Pickering emulsion stabilized with Lecithin modified kaolinite was80.83%.3)Two modified kaolinite with different hydrophilic and lipophilic properties was used as emulsifiers to prepare W/O/W double Pickering emulsions.The prepared W1/O/W2 double Pickering emulsion,its internal phase?W1/O?was stabilized with lipophilic kaolinite?the contact angle of 130°?and the external phase?O/W2?was stabilized with hydaophilic kaolinite?the contact angle of 88°?,could simultaneously encapsulate water-soluble catechin and oil-soluble curcumin.The co-stabilization of the double Pickering emulsion was demonstrated by the co-loading of curcumin and catechin compared to the double emulsion of the unencapsulated drugs.In the synergistic encapsulation emulsion,the encapsulation efficiency of curcumin and catechin reached 94-98%,which was increased by nearly 10%compared to that of the the simple emulsion encapsulated by curcumin or catechin alone.The synergistic release activity of curcumin and catechin encapsulated in double emulsion was evaluated in simulated gastrointestinal fluids,the release rate of curcumin and catechin was almost the same in the double emulsion compared to the simple emulsion loaded with curcumin or catechin,indicating that the catechin and curcumin encapsulated in the double emulsion had a synergistic release effect.