Effect of soybean protein isolate-pectin composite nanoparticles and hydroxypropyl methyl cellulose on the formation, stabilization and lipidolysis of food-grade emulsions

The formation and stabilization mechanism as well as digestion characteristics of food-grade emulsions prepared by the SPNPs-HPMC mixed systems (a combination of soybean protein isolate-pectin composite nanoparticles (SPNPs) and hydroxypropyl methylcellulose (HPMC)) were investigated. Then, it was found that the SPNPs-HPMC mixed systems could not only enhance the stability of the emulsion, but also make it have a satisfactory lipidolys is efficiency. During the formation and stabilization of the emulsion, HPMC was adsorbed in the early stage of emulsion formation, while SPNPs needed a longer adsorption time. When the HPMC concentration was 0.25-0.5 wt%, HPMC and SPNPs co-adsorbed on the interface. When the HPMC concentration was 1-2 wt%, HPMC and SPNPs competed to adsorb on the interface, of which the adsorption HPMC was dominant. In vitro simulation of digestion, SPNPs were decomposed into substances with lower interfacial activity, and the structure and activity of HPMC were well maintained, which led them to reconstruct a new interface layer. Thus, the size distribution and surface area of the emulsion droplets were retained in a good state for the lipidolysis process. Therefore, the SPNPs-HPMC mixed systems could both enhance the stability of the emulsion and grant it a satisfactory lipidolysis efficiency.