Effect of High Pressure Treatment on Interfacial Properties, Structure and Oxidative Stability of Soy Protein Isolate-Stabilized Emulsions

The effect of high pressure homogenization (HPH) treatment (40 to 200MPa) on the structure, interfacial properties and oxidative stability of soy protein isolate emulsions were investigated. After HPH process, emulsifying activity (EAI) and emulsion stability (ESI) could be improved by 114% and 125%, percentage of protein adsorbed to oil-in-water emulsions significantly improved when the pressure was not more than 160 MPa. SDS-PAGE showed that the HPH caused more low molecular mass subunits as the samples were treated below 160 MPa. FTIR traced the changes of four conformations in the secondary structure. Within a suitable pressure range, the apparent viscosity increased with the increasing of pressure, which reflected shear thinning; rheological measurement of emulsions showed G'>G '', G' and G ''' both increased significantly with frequency increasing; emulsions treated by HPH had better oxidative stability. This paper suggested the HPH was a useful method for preparation the highly viscous and stable emulsions.