Evaluation of ethyl carbamate formation in Luzhou-flavor spirit during distillation and storage processes

Ethyl carbamate (EC) is a toxic contaminant that poses hazard to humans due to its potential carcinogenicity. This compound has been widely detected in fermented foods and alcoholic beverages such as Chinese spirits. Clarifying the mechanism of EC formation is difficult but necessary for reducing EC levels in Chinese spirits because of their complex fermentation procedures. The formation of ethyl carbamate during distillation and spirit aging were evaluated in this study. All grains used as materials for producing Luzhou-flavor spirit contained ethyl carbamate precursors, urea and citrulline. The highest levels of urea (93 μg/kg) and citrulline (83 μg/kg) were detected in wheat and sorghum, respectively. EC and its precursors were introduced into the raw spirit of Luzhou-flavor spirit during distillation. EC, which was present at 92 μg/l concentration in raw spirit, came from the distillation process. EC content in the raw spirit increased to 66% during the first year of storage because of spontaneous formation of EC from its precursors mainly urea in the raw spirit.