Study On The Properties Of Soybean Protein-Epigallocatechin Gallate Nanoparticles And Pickering Emulsion

Pickering emulsion is a kind of emulsion stabilized by solid particles.It has strong anti-agglomeration ability which traditional emulsion does not have.Since much research on Pickering emulsion has focused on the use of inorganic particles,such as silica or modified silica particles,such inorganic particles are generally not biodegradable.Therefore,there is increasing interest in using food-grade particles from organic and natural sources.Soybean protein is often used as a food-grade particle as a stabilizer for Pickering emulsion due to its high nutritional value,good functionality,and low cost.EGCG is a water-soluble polyphenolic substance that is associated with many health benefits,such as antioxidant,anti-inflammatory,and anti-cancer properties.In this paper,the properties of nanoparticles which formed by soybean protein(SPI)and epigallocatechin gallate(EGCG),and Pickering emulsions stabilized by the nanoparticles were studied.The main content of this article is as follows:Using SPI and EGCG as raw materials,SPI-EGCG nanoparticles were formed by heat treatment(95?,20 min)at different molar ratios(1:0-1:4).Nanoparticles were characterized by particle size,Zeta-potential,and surface hydrophobicity.The antioxidant ability and foaming properties of the SPI-EGCG nanoparticles were evaluated.At the same time,the micromorphology of the nanoparticles was measured by cryo-electron microscopy characterized.The results showed that the optimal molar ratio of SPI to EGCG was 1:4,and SPI-EGCG nanoparticles with a particle size of 28.2 nm,a Zeta-potential of-27.53 m V,and a surface hydrophobicity of 1678.1 were prepared.The nanoparticles have strong oxidation resistance and foaming characteristics.The DPPH and ABTS radical scavenging rates are 30.23%and 58.96%,respectively.The foam expansion and foam stability are 150.77%and 115.38%,respectively.Cryo-electron microscopy observations revealed that the nanoparticles were densely packed and the particle size was relatively uniform at this molar ratio.A kind of protein-polyphenol nanocomposite with good properties has been developed,which was also a new Pickering stabilizer.Pickering emulsion were prepared using SPI-EGCG nanoparticles formed at the above mole ratio.Meanwhile,the Pickering emulsion was characterized by particle size and Zeta-potential.Optical microscopy and cryo-electron microscopy were used to characterize the micromorphology of Pickering emulsion.The results show that as the molar ratio of SPI to EGCG increases,the particle size of Pickering emulsion decreases from 44?m to 22?m;Zeta-potential absolute value increased from 6.03 m V to 18.46 m V;Emulsifying activity and emulsion stability increased by32.25 m~2/g and 98.16 min,respectively;The scavenging rates of DPPH and ABTS free radicals of Pickering emulsion increased by 49.41%and 27.86%,respectively.Creaming index decreased to46.75%at seventh week;The optical microscope observed that the emulsion droplets became smaller and smaller,and the degree of coalescence was significantly improved,and the droplets became more and more uniform;Cryo-electron microscopy observations revealed that there are more and more bridge-like three-dimensional network structures formed by Pickering emulsion.Finally,a new food grade Pickering emulsion with relatively stable and good oxidation resistance and emulsifying properties was obtained.