Anti-foaming agent

An antifoaming agent is a chemical additive that inhibits the formation of foam.

In Engine Motor Oil
When used as an oil additive to the base stock of oil, antifoam agents prevent the oil from foaming and frothing during high speed mechanical agitation.

In Food and Pharmaceuticals
When used as an ingredient in food, it is intended to curb effusion or effervescence in preparation or serving. Antifoaming agents are included in a variety of foods such as Diet Pepsi, Diet Coke, Sprite, and chicken nuggets in the form of polydimethylsiloxane (a type of silicone). Antifoaming agents are also sold commercially to relieve bloating. A familiar example is the drug Simethicone, which is the active ingredient in drugs such as Gas-X.

Silicone oil is also added to cooking oil to prevent foaming in deep-frying.

See Ingredients for McDonalds Foods for common examples of antifoaming agents in commonly served foods.