Techniques that inflate foods with air or gas to create open, crunchy, or airy textures. The toolbox includes injecting air, carbon dioxide, nitrogen, or nitrous oxide; forcing doughs through an extruder so they expand on exiting the die; dissolving gas under pressure into syrups, fat blends, or chocolate and then releasing it; and the classic gun-puffing of cereals, where superheated moisture bursts the grain when pressure drops. Each route gives a different cell structure, and formulators balance expansion against flavor, nutrition, and the packaging needed to protect fragile textures.