Study On Ethyl Carbamate In The Production Of Chinese Rice Wine

Ethyl Carbamate(EC) is a kind of concomitant in product of fermented food and fermented beverage. Studies have shown that it is a potential carcinogen, which can cause lung cancer, liver cancer, lymphoma and other diseases, IARC classifies it as a Class 2A carcinogen. The international community has put the EC content as one of the important indicators to evaluate the wine. In all kinds of fermented wine, the EC problem is particularly prominent, which seriously affected the safety of Chinese rice wine. This study focused on the process of Chinese rice wine, we have a preliminary study on the EC and the formation of EC related substances, in order to provide a reference for the detection of EC and control the quality of Chinese rice wine. The main findings are as follows:(1) The D5-EC was used as the internal standard for the quantitative determination. The LC separation was performed on a Waters HPLC system with a SunFireTM C18 column, methanol and 0.1%(v/v)acetic acid aqueous solution as the mobile phase. The ethyl carbamate was determined in the mode of electrospray positive ionization(ESI+) and multiple reaction monitoring(MRM). The correlation coefficients were good in the range of 2~500μg/L, the correlation coefficient was 0.9942,with a limit of detection of 1.8μg/L and limit of quantity of 5.0μg/L. Average recoveries of ethyl carbamate were88.9%~103.1%, RSD were in the range of 1.8%~5.6%. Compared with the national standard method, the results of this method have no significant difference. The method can be used for the rapid detection of EC in Chinese rice wine.(2) Study on EC formation mechanism of citrulline, urea and ethanol reaction in a heated state. It confirmed that citrullineis is the important precursors of EC formation in Chinese rice Wine.(3) We measured the physical and chemical indexes of yellow rice wine, such as urea content, alcohol content, total sugar, total acid and amino acid, then analyzed the correlation between them and EC content. The results showed that EC and urea, arginine and ornithine were significant at 0.05 level, the correlation coefficient is-0.643,-0.760, 0.651. EC and citrulline presented in the 0.01 level was significantly correlated, the correlation coefficient is-0.857. Through linear regression analysis, the EC as dependent variable, with urea and citrulline and ornithine, arginine as the independent variable, linear equations for Y=203.385-5.096X1+0.114X2+0.314X3-5.564X4.(the Yfor EC, 203.385 for constant, X1, citrulline, X2, arginine, X3 ornithine, X4 urea).(4) Tracking and analysis of EC and related substances in the whole process of the production of yellow rice wine. The results showed that the content of EC in the whole fermentation stage was relatively low, and the content of EC was 2.34 times of that before heating. In the storage stage, with the extension of storage time, the EC content showed an increasing trend. In the whole process of production, the content of urea increased first and then decreased, then increased and then decreased, and finally stabilized. The content of arginine decreased first, but then increased, then decreased, and then left. Citrulline content increased first, then decreased, and then tends to be stable. The content of ornithine is increased at first and then decreased, and finally tends to be stable.(5) We study on EC and climatic and environmental factors(monthly sunshine duration, monthly mean relative humidity, monthly precipitation, monthly mean temperature, ultraviolet strength) were analyzed in different months and years of production of Chinese rice wine.The results show that EC and monthly average temperature, UV intensity and monthly precipitation is significant and has positive correlation. The content of EC was the lowest in January, and the highest content of EC was produced in September. We study on storage conditions at 0℃, 4℃, 15℃, 25℃, 35℃stored for 12 months, found that when stored under natural conditions, the average monthly increase respectively 1.31μg/L, 1.32μ g/L, 2.33μg/L, 3.03μg/L, 3.95μg/L respectively. Under dark conditions of storage, the monthly increase of 1.20μg/L, 1.45μg/L, 2.00μg/L, 2.79μg/L,3.43μg/L. The results showed that the production of EC was significantly decreased at low temperature and dark condition...