The influence of chitosan and gum arabic mixtures on the behaviour of o/w emulsions has been
investigated at pH ¼ 3.0. The emulsion behaviour, properties and microstructure were found to be
greatly dependent on the precise gum arabic to chitosan ratio. Mixing of gum arabic with chitosan leads
to the formation of coacervates of a size dependent on their ratio. Incorporation of low gum arabic to
chitosan weight ratios into whey protein-coated emulsions causes depletion flocculation and gravityinduced
phase separation. Increasing the polysaccharide weight ratio further, a droplet network with
a rather high viscosity (at low shear stress) is generated, which prevents or even inhibits phase separation.
At even higher gum arabic to chitosan ratios, the emulsion droplets were immobilised into
clusters of an insoluble ternary matrix. Although the emulsion droplet charge had the same sign as that
of the coacervates, clusters of oil droplets in a ternary matrix were generated. A mechanism to explain
the behaviour of the whey protein-stabilised o/w emulsions is described on the basis of confocal and
phase contrast microscopic observations, rheological data, zeta potential measurements, particle size
analysis and visual assessment of the macroscopic phase separation events.