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Foam (culinary)


The use of foam in cuisine has been present in many forms in the history of cooking. For example, whipped cream, meringue, and mousse are all foams. In these cases, the incorporation of air or another gas creates a lighter texture and/or different mouth feel. More recently, foams have become a part of molecular gastronomy technique. In these cases, natural flavors (such as fruit juices, infusions of aromatic herbs, etc.) are mixed with a neutrally-flavored gelling or stabilizing agent such as agar or lecithin, and either whipped with a hand-held immersion blender or extruded through a whipped cream canister equipped with nitrous oxide cartridges. Such foams add flavor without significant substance, and thus allow cooks to integrate new flavors without changing the physical composition of a dish. Some famous food-foams are foamed espresso, foamed mushroom, foamed beet and foamed coconut. An espuma or thermo whip is commonly used to make these foams through the making of a stock, creating a gel and extruding through the nitrous oxide canister.

To form a stable foam and emulsion, a surfactant, such as lecithin, monoglycerides or proteins, must be present to reduce the interfacial tension between the air/oil phase and the aqueous phase. If the surfactants are at equal concentrations at the interface, proteins are generally less effective than small surfactants, such as lecithin or monoglycerides, at decreasing the interfacial tension.

Foams consist of two phases, an aqueous phase and a gaseous (air) phase. Foams have been used in many forms in the history of cooking, for example: whipped cream, ice cream, cakes, meringue, bread, soufflés, mousse and marshmallow. It has a unique light texture because of the tiny air bubbles and/or a different mouth feel. In most of these products, proteins are the main surface active agents that help in the formation and stabilization of the dispersed gas phase. To create a protein-stabilized foam, it usually involves bubbling, whipping or shaking a protein solution and its foaming properties refers to its capacity to form a thin tenacious film at the gas-liquid interface for large amounts of gas bubbles to become incorporated and stabilized.


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