23butanedione

2,3-Butanedione, commonly known as diacetyl, is an organic diketone with the formula C4H6O2. Its structure is CH3-CO-CO-CH3, giving it a volatile, low-viscosity character. Diacetyl is a colorless to pale yellow liquid with a distinctive buttery aroma.

Occurrence and production

Diacetyl occurs naturally in trace amounts in dairy products, butter, cheese, and some fermented beverages. It is produced by various microorganisms, including lactic acid bacteria and yeast, during fermentation. Industrially, it can be produced synthetically by chemical methods or obtained as a byproduct of fermentation processes used to flavor foods.

Uses

The primary use of diacetyl is as a flavoring agent to impart a butter-like note in foods such as popcorn, baked goods, margarine, and dairy products. It is typically used in very small quantities due to its potent aroma. Diacetyl has also been used in some cosmetic and beverage applications, but its use is most closely associated with food flavoring.

Safety and regulation

Diacetyl is flammable and should be handled with appropriate precautions to avoid inhalation or contact with skin and eyes. Inhalation of diacetyl vapors has been linked to severe respiratory illnesses, including bronchiolitis obliterans, particularly among workers in microwave popcorn production and related industries. Therefore, occupational exposure limits exist in some jurisdictions, and exposure control measures are recommended. Ingestion is less hazardous than inhalation, but high doses can still cause irritation.

See also

Acetoin, another related fermentation product involved in dairy flavor development.