Surface Topography of Heat-Set Whey Protein Gels: Effects of Added Salt and Xanthan Gum - Food Colloids: Self-Assembly and Material Science - page 478

Figure 3 CLSM images of the surface of heat-set whey protein gels: (a) no added salt;
(b) 200 mM NaCl. The inset in (b) is an enlargement of the tips of the surface
asperities
explanation is surface evaporation. The upward mass transport of water may
cause protein aggregates to become oriented. But this seems unlikely, considering
the fact that the gelation was carried out in well-sealed dishes with a small head
space. Another possible explanation would be a different assembly mechanism of
the protein aggregates at the surface. While protein clusters may diffuse and
aggregate in any direction in the bulk phase, protein aggregation at the surface is
only possible in lateral directions and from beneath.
33.3.2 Effect of Added Xanthan Gum
The presence of a small amount of the hydrocolloid, xanthan gum, produces a
dramatic effects on the topographical features of the heat-set whey protein gels.