cations could be utilized as a density adjuster of emulsion oil
droplets if they adsorb at the oilewater interface.
Fig. 3 shows microstructural images of SPI gel particles obtained
by light microscopy. The SPI gel particles with no added salts
seemed to be dispersed in the aqueous phase as well as the original
SPI particles without the gelation, whereas the SPI gel particles
with Ca2þ and Mg2þ formed relatively large aggregates after homogenization.
These results correspond to those obtained by the
short-term storage test described above, which suggests that the
different gravitational behaviour depending on the type of added
salt can be explained by the different structural features of the
aggregates, such as different degrees of compactness or fractal
geometry, probably caused by the different screening effects.
Similar results were obtained for the LMW-SPI gel particles.