Preparation And Interfacial Mechanism Of Ginger Oil Pickering Emulsion Stabilized By Cyclodextrin Microcrystals

In the research and development or production of food and beverage products,it is necessary to apply essential oil to food additives with certain encapsulation technology to enhance the flavor of food or cover up the bad flavor of food.Cyclodextrins(CDs)combined with oil and other guest molecules to form amphiphilic inclusion complexes adsorbed on the interface between the oil phase and the water phase,which reduces the interfacial tension and forms a stable Pickering emulsion.In this paper,the raw ginger oil Pickering emulsion with α-cyclodextrin(α-CD),β-cyclodextrin(β-CD)and γ-cyclodextrin(γ-CD)as solid particle emulsifiers was prepared by different methods,and the formation process of β-CD stabilized Pickering emulsion was studied.Firstly,ginger oil/CDs Pickering emulsion was prepared by high-speed shear emulsification and ball milling without adding external emulsifier,and the stability of the emulsion was characterized by microscopic observation,dyeing analysis and emulsification index(CI).The results showed that the three kinds of cyclodextrins could not form Pickering emulsion at low concentration and had obvious oil-water separation.Only β-cyclodextrin particles participate in the flocculation phenomenon of stabilizing the original fragrant ginger oil Pickering emulsion is more serious,the surface of the emulsion droplets is rough and has lamellar particles.Secondly,by observing and comparing the apparent characteristics of Pickering emulsion formed by different types of cyclodextrin,it was found that the emulsion formed byβ-CD is relatively good,so we focus on the system of β-CD.In the process of emulsion preparation,the subtle changes of β-CD in the process of droplet formation are easy to be ignored.In order to study the formation process of lamellar particles at the oil-water interface,the original ginger oil was prepared by ball milling method.The inclusion compound particles were characterized and analyzed by Fourier transform infrared spectroscopy(FTIR),optical contact angle meter,interfacial tension meter,X-ray diffraction(XRD)and scanning electron microscope(SEM)β-CD and ginger oil first form amphiphilic nanoparticles through host-guest interaction,and the formed particles further self-assemble to form lamellar micro-crystal of amphiphilic inclusion complex.These amphiphilic particles and microcrystals can aggregate at the oil-water interface to form Pickering emulsion.Finally,through simple oil-water experiments and capturing the dynamic process of cyclodextrin microcrystals at the oil-water interface with a camera,the morphological evolution law of self-assembly and the influence of interfacial adsorption behavior on emulsion stability were revealed.In this study,through the exploration of the formation process and evolution law of ginger oil/β-CD self-assembly,the formation process and stabilization mechanism of β-CD stabilized ginger oil Pickering emulsion were clarified,which provided a theoretical basis for the development of high performance CDs stabilized Pickering emulsion.