4. Mechanisms of destabilization and alteration of frozen desserts during storage

4.1 Coalescence

The air bubbles are surrounded by a thin, more or less viscous film of liquid prior to freezing. The more or less rapid downward flow of this liquid film, due to gravity, causes it to break. This causes the air bubbles to coalesce, fusing them together and making them larger. The speed of coalescence increases with bubble size, and coalescence spreads to neighbouring bubbles.

The bubbles in a foam are not all of the same size, generating pressure differences; the pressure inside large bubbles is lower than inside small bubbles. The pressure...