Royal icing (sugar with extended egg albumen) and glacé icing (sugar only) were examined by light microscopy and environmental scanning electron microscopy. These techniques allow a variety of structural information to be characterized without damage occurring to the specimen. Microstructures were compared in an effort to explain the enhanced hardness and toughness exhibited by Royal icing. The inclusion of extended egg albumen was found to affect both the nucleation and the growth of crystalline material in the icing. The extended egg albumen promoted spherulitic morphologies, finer-scale microstructures, multiple phases, and improved interlocking and cohesion at internal interfaces. The retention of air bubbles in Royal icing provided additional sites at which crack growth could be arrested.
- Egg albumen
- Environmental scanning electron microscopy
- Polarized light microscopy