Droplet ¯occulation caused a signi®cant increase in
the creaming rate of the droplets in the emulsions (Fig.
4). In the absence of CaCl2 the emulsions were relatively
stable to creaming at low and high pH, but were highly
unstable around the isoelectric point of the proteins.
The addition of CaCl2 had a signi®cant impact on the
pH dependence of the creaming stability of the emulsions. At pH values signi®cantly below the isoelectric
point of the proteins (pH < 4.5) all of the emulsions
were relatively stable to creaming. At pH values above
the isoelectric point the emulsions were relatively stable
to creaming below a certain CaCl2 concentration, but
became unstable when this concentration was exceeded.
This critical CaCl2 concentration increased as the pH
moved further away from the isoelectric point. Above
about 5 mM CaCl2 all of the emulsions were unstable to
creaming above the isoelectric point.