A foaming composition includes a powdered carbohydrate-free soluble composition which includes protein particles having a plurality of internal voids containing entrapped pressurized gas. In one form, the foaming composition is produced by subjecting the particles to an external gas pressure exceeding atmospheric pressure prior to or while heating the particles to a temperature of at least the glass transition temperature and then cooling the particles to a temperature below the glass transition temperature prior to or while releasing the external pressure in a manner effective to trap the pressurized gas within the internal voids.