3-Hydroxybutanone

3-Hydroxybutanone, also known as acetoin or acetyl methyl carbinol, is a chemical compound composed of carbon, hydrogen and oxygen. Its formula is C4H8O2. It is a colourless or pale yellow to green yellow liquid with a pleasant buttery odour. It is used as a food flavoring (baked goods) and a fragrance. It can be found in apples, butter, yogurt, asparagus, black currants, blackberry, wheat, broccoli, brussel sprouts, cantaloupe.

Cigarette additive
In a 1994 report released by five top cigarette companies, acetoin was listed as one of the 599 additives to cigarettes.