Ethyl carbamate formation regulated by ornithine transcarbamylase and urea metabolism in the processing of Chinese yellow rice wine

Summary Ethyl carbamate (EC) is a potential carcinogenic compound present in most of the fermented foods. In this work, EC was inhibited through different strategies during vinification of Chinese yellow rice wine. EC can be inhibited by the use of ornithine in contrast to the control at peak point. However, the utilisation of urease resulted in little inhibitive effect on EC. The comparative data of intracellular ornithine transcarbamylase (OTCase) and arginine deiminase (ADI) among four experiments showed that EC was positively regulated by intracellular OTCase, but ADI was not determined. Extracellular urea and citrulline content was significantly increased by adding ornithine (P < 0.05), whereas ethanol played a minor role in EC formation. The correlation analysis between EC and OTCase or urea revealed a linear association (correlation coefficients above 0.8). These findings suggested that OTCase may be a required factor regulating EC formation during the brewing of Chinese yellow rice wine.