Many proteins are highly effective emulsifiers because they contain both hydrophobic regions
and charged hydrophilic regions, which lower the surface tension and interact at the
emulsion interface. Proteins can stabilize emulsions because their hydrophobic amino acids
partition into the surface of the freshly formed oil droplet and cause the protein to stick at
the oil-water interface (Fig. 1). The adsorbed layer gives some stability by shielding the oil
from the aqueous phase but the proteins now to a great extent control the functional
properties of the system. On the other hand, proteins may remain attached to fat droplets,
but aggregate together in high temperature conditions, causing clumping of protein/fat
globules. In reality, these behaviors are not just due to changes in temperature. The types
of proteins present, emulsifying agents, ion concentrations, pH, the presence of other
ingredients and factors all come together with the mix temperature to affect the stability
and effectiveness of the emulsion.