We studied the influence of addition of polysaccharide (exemplified by -carrageenan) to gelatin solution
on the rheological properties, morphology, and stability of highly concentrated oil-in-water emulsions. Gelatin and -carrageenan form polyelectrolyte complexes which stabilise emulsions. At some
-carrageenan/gelatin w/w ratios less than 0.7 (gcar/ggel), these components form a stoichiometric complex which is in dynamic equilibrium when gelatin is in excess. At a -carrageenan/gelatin w/w ratio
≤0.1, the emulsions are stable against coalescence in the long-term but not against sedimentation. At
ratios from 0.1 to 0.14, emulsions are stable against sedimentation. Highly concentrated emulsions at the
dispersed phase content of 74–75% stabilised by gelatin–-carrageenan polyelectrolyte complexes are
viscoplastic media (shear-unstable gels) and the clearly expressed yielding behaviour and the domain
of the so-called “apparent” maximum Newtonian viscosity can be still detected. Solid-like behaviour of
highly concentrated emulsions at low stresses is characterised by constant values of the storage modulus
in a wide frequency range. The rheology of the emulsions under investigation depends on the ratio of
components in the systems. An increase in the concentration of the gelatin–-carrageenan complexes
(and consequently, the decrease in unbound gelatin) leads to a decrease in the emulsion viscosity, storage
modulus, and yield stress with a tendency to disappear solid-like properties