Microscopy images in Fig. 1 reveal that particles prepared with
higher calcium concentrations (100 and 400 mM) showed thinner
interfacial protein shells compared to particles prepared with a
lower calcium concentration (30 mM) (compare Fig. 1C and D),
probably as a result of lower affinity for the interface. The affinity
of the proteins for the interface may be maximal at certain intermediate
calcium concentration and may then decrease with additional
calcium. For higher calcium concentrations, less protein is
accumulated at the surface and is still present in the centre of
the droplet.