In the culinary world, foams and espumas are gaining in popularity. To create foams or a mousse, air or gas is mechanically pumped into a liquid. The addition of stabilisers helps to maintain the expansion1.The mixture then needs to be stabilised to hold it in place, otherwise the air will simply escape. Air is not retained in whisked water.
The stabilising agents are emulsifiers. These can be phospholipids (lipids containing phosphoric acid) such as soya lecithin or protein such as ovalbumin2 found in eggs. Interestingly, carrots also contain phospholipids. If air is pumped into carrot juice, the phospholipids in the cell membranes become active once the cell walls are mechanically broken down, creating a foam.