Espuma

In cuisine, foam is a gelled or stabilized liquid in which air is suspended. Foams have been present in many forms over the history of cooking, such as whipped cream, meringue and mousse. In these cases, the incorporation of air, or another gas, creates a lighter texture and a different mouthfeel. Foams add flavor without significant substance, and thus allow cooks to integrate new flavors without changing the physical composition of a dish.

Wikipedia →