In order to enhance functional properties of commercial soybean protein isolate (SPI), SPI microgel
particles as foaming and emulsifying agents were studied. Microparticulation of heat-set SPI macrogels
containing no added and various added salts was systematically carried out using a high-speed blender,
an ultrasonicator and a high-pressure jet homogenizer. Among the tested conditions, the smallest gel
particles were achieved via the high-pressure jet homogenization process under conditions of no added
salts. Conversion of ordinary high molecular weight commercial SPI into the counterpart gel particles
enhanced foam stabilizing properties of the suspensions and stability against creaming and freeze-thaw
triggered instability of the emulsions, while the enhancement was not necessarily achieved for lowmolecular-
weight partially hydrolysed SPI. This can be attributed to the different steric repulsive effects
of the gel particles.