Structural Manipulation And Application Of Soy Protein Microparticles

As there is an increasing focus on health and environmental issues,plant-based food has attracted much attention.However,due to the poor dispersity and undesirable taste of plant protein ingredients,the quality of the plant-based food still fails to meet consumers'expectations.Microparticulation,which turned the food proteins into particles in micro-scale with the help of heating and spray drying,had been performed on commercial soy protein isolate(SPI)to improve its quality in this study.During the preparation of soy protein particulates,the microstructure of particles was modified via adjusting p H and adding calcium ions.The effect of microstructure on the stability and functional properties of obtained microparticles was also investigated,and the application of microparticulation in the preparation of the high energy density emulsion was also studied.The main conclusions are as follows:1.SPI was subjected to microparticulation,and the effect of p H conditions during heating on the microstructure and functional properties of the resultant particles were investigated.It was found that soy protein particles with different particle sizes,structures,and function properties could be obtained by adjusting the p H conditions.When microparticulation was conducted at p H 5.0,more hydrophobic groups of the protein were buried inside,forming microparticles with compact conformation.Compared with those prepared at neutral conditions(p H 6.0 and 7.0),microparticles prepared at p H 5.0 had better fluidity,dispersibility,and stability.2.Calcium chloride was introduced in soy protein microparticulation,and its effect on the stability and functional properties of soy protein microparticles was investigated.Results indicated that the presence of calcium ion reduced the particle size and maintained the particle structure when exposed to high temperature,due to the formation of the salt bridge inside protein particles.Particles with 25 m M Ca²⁺addition had a higher calcium-binding rate and better thermal stability than other particles,which could be used as fat substitutes and foam stabilizers in the preparation of plant-based whipped cream.3.Plant-based high energy density emulsion with low viscosity,smooth taste,and desirable stability was prepared by homogenization and microparticulation.In this study,p H conditions and protein concentration were found to be key factors.Results indicated that protein molecules that were not adsorbed at the oil/water interface affecting the stability of the emulsion.A special microstructure in which oil droplets and protein microparticles co-existed was created by manipulating the p H condition during microparticulation.Besides,sucrose and other ingredients were also introduced to improve the stability of the emulsion.