Ethyl carbamate also called urethane (C3H7NO2) or carbamide acid may be occurred in traces in all fermented foods. Formation is made through metabolic activity from urea and different amino acids such like ornithine and citrulline.
In wine and sparkling wine
Ethyl carbamate is formed in wine in the following way:
Arginine is the mostly occurring amino acid in must. This amino acid serves yeasts as nitrogen source into must. Yeast absorbs this substance and metabolizes it to urea.
If yeast cells are not able to metabolized urea and this substance is in critical concentration, yeast cells give off the substance to wine during or after the fermentation. Then urea reacts with wine alcohol to ethyl carbamate. This chemical reaction between urea and ethanol exponentially increase at high temperatures. EU has no maximum level for ethyl carbamate in wine, whereby Canada has maximum levels from 30 µg/kg in table wine to 100 µg/kg in fortified wines.
In spirits
Due to higher concentrations of cyanide especially in stone fruit spirits, risk of occurrence of ethyl carbamate is much higher, because this substance can be formed from cyanide. Brands with elevated ethyl carbamate contents are seen as unfit for the human consumption, and therefore these products are objected governmentally. For this reason, the analysis of ethyl carbamate is useful for these products.
In other products
Ethyl carbamate can appear, in other fermented products like beer with low content as well as into wine, so that for these products the analysis of ethyl carbamate is useful for example for Export to verify maximum levels.
- Method
- Limit of detection
- Naturally Content (wine)
- Reason for the analysis
- GC-MS
- 35 µg/L
- not present
- Control of legal limits