Study Of Zein Self-assembly Using Ultrasonic Anti-solvent Membrane Dialysis Process

Zein is a major storage protein from corn with strong hydrophobicity and unique solubility.It can self-assemble to form microspheres or films because of its amphiphilicity.The formation of Zein particles has been particularly investigated for the development of drug and nutrients delivery systems,Zein microspheres with controllable particle size could be prepared by controlling the process parameters.However,the mechanism of Zein self-assembly is still a challenge.In this work,Zein self-assembly mechanism in different conditions was studied based on Built-in Ultrasonic Dialysis Process(BUDP).SEM results indicated that the mechanism of Zein self-assembly during BUDP included two parts,the droplets break-up by coustic cavitation and the self-assembly and solidification of Zein spheres during dialysis.CD results suggested that Zein conformation transformed from ?-helix to ?-sheet as the ethanol content of the solution decreased during BUDP.Also,the structure transitions and size distribution were significantly affected by pH,ionic strength and addition of surface active compounds.Combining ultrasonication and porous hollow fiber membranes,a novel technique for continuously producing monodispersed particles by anti-solvent precipitation was developed,which derived from BUDP.The results indicated that ultrasonication could reduce the steady state permeation time and improve the efficiency of mass transfer.The residence time played an important role in Zein precipitation,and could be altered by changing the tude-side feed solution flow rate and the shell-side anti-solvent flow rate.SEM results indicated that ultrasound power,Zein concentration and the mass ratios of curcumin to Zein had a significant effect on the formation of Zein microspheres and size distribution.This technique meets the needs of continuous production and has a prospect of application in crystallization or encapsulation.This study improves the understanding of Zein self-assembly mechanism during BUDP,which will be helpful for the applications of Zein in drug and nutrients delivery system.