The Formation Of Ethyl Carbamate In Soy Sauce

In 2007, The World Health Organization’s International Agency for Research on cancer(IARC) re-classified Ethyl carbamate(EC) as a group 2A carcinogen. Most alcoholic beverages and fermented foods contains trace amounts of EC. Many countries have set the upper limits of EC in alcoholic beverages. Soy sauce, where EC has been detected, is a Chinese traditional condiment. It plays an important role in people’s diet life, but there is no limit standard of EC and study about the formation of EC in it.In this study, the high-salt liquid fermentation and low-salt solid fermentation was simulated just as the soy sauce industry required. The concentrations of EC, urea, arginine, citrulline and ornithine in sauces during fermentation were analyzed. Using the relationships between them to analyze the metabolism mechanism of EC during soy sauce fermentation. Determination of EC using the method AOAC994.07, urea concentration was analyzed by HPCL-PDA, the concentration of arginine, citrulline and ornithine were determined by HPLC-FLD.Divided soy sauce into two groups, group 1 and group 2, group 2 was in presence of Saccharomyces rouxii. In high-salt liquid fermentation sauce, EC was increased in both groups, contained 34.22 and 64.49μg/L of EC in the end, respectively; in low-salt solid fermentation sauce, EC concetration increased from 10.63 to 43.56μg/L, then decrease to 33.26μg/L in group 1 and increased from 10.63 to 50.86μg/L, then decrease to 44.86μg/L in group 2. This showed that both Aspergillus oryzae and Saccharomyces rouxii can cause the formation of EC and different fermentation procedures influenced EC formation, EC concentration raised with time and temperature.Urea was found to have the same trend with EC, this proved that urea was related to EC. The decrease of citrulline indicated that Aspergillus oryzae may metabolized citrulline in another unidentified way.In conclusion, Aspergillus oryzae and Saccharomyces rouxii can cause the formation of EC. Urea and citrulline as precursors influenced the formation of EC during fermentation.