Diacétyle

|---- |Other names || butadione |---- | Notation SPALLING HAMMERS ||DC (=O) C (C)=O |---- |----- |----- |----- | Not of boiling || 88° C under 1 bar |----- |----- Steam pressure || 141 hPa (20 °C) |----- | Acidity (pKa) || 0,3 |----- ! colspan=" 2" bgcolor=" #FFDEAD" | Related compounds |----- | Others Acid S || CH₃COOH
CCl₃COOH |----- ! colspan=" 2" bgcolor=" #FFDEAD" | Card-index dangers |----- | || |----- | Principal dangers || Highly corrosive |----- | NFPA 704 || |----- | Card-index safety || Baker
Fischer |----- | Not flash || 270 K |----- | Codes R/S || Sentences of risk: |----- | ||R 20, R 35, R 52/53 |----- | || the Councils of prudence: |----- | || S9, S26, S27 |----- | || S28, S45, S61 |----- | Number RTECS || AJ9625000 |----- -->

The diacétyle or Butanedione C₄H₆O₂ is a Cétone liquid, bird, yellow, with odor of Fromage or fermented perspiration (dirty feet, armpits). Present in butter, fresh creams, lacteous products, wines, the butanedione has the note characteristic of butter. This molecule is formed when one incubates the cream with bacteria. After the Incubation, the cream is beaten. The envelopes which surround the droplets of grease are thus broken: those amalgamate then in a mass. Milks of ewe and Chèvre are richer than the cow's milk in Triglycéride S: the cheese manufactured with these milks, as the roquefort is thus richer in molecules with prickly taste. The butadione is present in the wines at amounts being able to reach 2 mg/l, but, in general, it is about 0,3 mg/l.

Alcoholic drinks

In the case of Wine S or of slightly alcoholized beers, the diacétyle contributes to a feeling of facility of absorbtion in mouth. When the degree of alcohol increases, the product gives a caramel or butter taste. This occurs during the fermentation during which a by-product of the Valine is formed. During this Synthesis, the Levure produces a α-acétolactate which, out of the cell, conduit to diacétyle by decarboxylation. The yeast absorbs then diacétyle and reduces the group Cétone to form 2-3 butane diol, an insipid compound.

Sometimes the Bière presents traces of diacétyle which cause a light rise in temperature during both or three days during which the Fermentation is carried out. This allows yeast aborber the diacétyle which it produced during the cycle of fermentation. The producers of Chardonnay support the production of diacétyle systematically because its contribution gives taste and savor. Its presence in the wines of this type of vine coming from California results in a tendency to offer savors close to the traditional French wines. One could measure contents of 0,005 mg/l with 1,7 mg/l in wines chardonnay, a minimum quantity of 0,2 mg/l allowing to detect a savor.

External bonds

the proportioning of diacétyle in butters
Improvement of the aromatic quality of fresh cheeses.

See too

Reaction of Voges-Proskauer

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