Urea Contribution to Ethyl Carbamate Formation in Commercial Wines During Storage

Abstract

A two-year storage test using commercial wines confirmed that ethyl carbamate formation is closely related to the urea content. The ethyl carbamate formation rates at 10°C to 40°C were represented by linear equation against urea concentration in wine. Mathematical evaluation of the equations indicated that urea content in wine should be reduced to less than 2 mg/L in order to keep the ethyl carbamate content within the current target levels of the wine industry: 15 µg/L in table wines and 60 µg/L in dessert wines. It was found that, upon storage for six months at 40°C, ethyl carbamate level of the wines treated with acid urease was significantly lower than that of the untreated wines. The activation energy to form ethyl carbamate in wine was found to range between 21 kcal/mol and 28 kcal/mol which is similar to the activation energy level in other systems such as Japanese sake and simulated wine (a model wine system).