Increased protein content in ice cream boosts nutritional value,
but it can also have a profound impact on structural elements,
particularly the formation of partially coalesced fat during freezing
(Segall & Goff, 1999). Proteins, usually present at about 4% in ice
cream, initially stabilize the lipid emulsion after homogenization by
forming a dense adsorbed layer on the fat globule interface, which
prevents the droplets from coalescing by steric repulsion
(Dickinson, 2003). However, each milk protein has differing
adsorption properties and functions at the interface including how
they unfold at the interface, how much they reduce the interfacial
tension, how densely packed they can become, and their typical
surface coverage. Each of these factors will have an impact on
emulsion stability and the propensity for an emulsion to undergo
partial coalescence during shear