Phase separation can be classified into aggregative and segregative
phase separation [5,6]. In general, segregative phase
separation induced by thermodynamic incompatibility occurs at
high ionic strengths and high polymer concentrations. The thermodynamic
incompatibility of proteins and polysaccharides has
been studied for more than hundred years [7]. Associative phase
separation which is known as complex coacervation occurs at
low ionic strengths and low polymer concentrations. Biopolymers
with opposite electric charges attract each other and separate into
two phases: one rich in both biopolymers and the other phase
depleted in biopolymers and consisting mainly of solvent [8]. In
more complex situation, three phases may also coexist [9]. Association
has also been found for slightly negatively charged gelatin
and KC mixture due to the presence of “patches”, positively charged
regions, on protein [10,11]. Associative phase separations between
polysaccharides and proteins have been widely investigated and
characterized by turbidity measurement, light scattering and other
physical measurements [12–14].