The Study Of Detecting EC/Urea/3-MCPD And Removing Ec/Urea In Chinese Rice Wine

Ethyl Carbamate（EC）is widely existent in fermented foods and alcoholic beverages.EC has been classified as a Group 2A carcinogen by the International Agency for Research on Cancer（IARC）.Chinese rice wine is one of the oldest alcoholic beverages in China.The special brewing process makes the EC content in Chinese rice wine is especially high,which seriously threatening the health of consumers.Therefore,the removal of EC in Chinese rice wine is urgently to be solved.In this paper,the Merrifield resin modified with 9-Xanthydrol was tested to remove EC and its precursor urea in Chinese rice wine.3-Chloro-1,2-propanediol（3-MCPD）is widely present in fermented foods such as soy sauce and rice wine.3-MCPD has been classified as a Group 2B carcinogen by IARC.The detection of 3-MCPD in food is difficult.In this process,3-MCPD was derived by azaidation coupled with click reaction.The derivative has ultraviolet absorption,which makes 3-MCPD to be quantitative analyzed by HPLC-UV in soy sauce and rice wine.The main contents are as following in details:1.The reactivity of 9-xanthydrol with amino acids and amides in Chinese rice wine was investigated.Firstly,xanthone was synthesized,then,it was reduced with NaBH₄,LiBH₄,Ca（BH₄）₂ and zinc powder,respectively.It’s found that NaBH₄ and zinc powder gave a good yield of 9-xanthydrol.Then,the reaction of 9-xanthydrol with amino acids and amides in simulated Chinese rice wine was tested.It’s found that 9-xanthydrol could not react with the eleven amino acids including asparagine and arginine in simulated Chinese rice wine,however,it could combine with EC and urea with yields above 90%after 12 h of reaction.2.The removal of EC and urea by Merrifield resin modified with 9-xanthydrol in Chinese rice wine was studied.First,xanthone isomers with methoxy group at different position were synthesized.Then the methyl group of methoxy was removed with pyridine hydrochloride,leading to phenol structure.The resultant phenols were further tethered on the Merrifield resin.Four kinds of xanthydrol modified Merrifield resin were produced（Xanthydrol-1-O-P,Xanthydrol-2-O-P,Xanthydrol-3-O-P,Xanthydrol-4-O-P）.The activities of them to remove EC and urea were then studied.Xanthydrol-4-O-P demonstrated most actively among them.When the weight ratio between resin and Chinese rice wine was 1:48,when the Chinese rice wine was supplemented with 3,6 and12μmol/L EC,the removal rates of EC were 61.54%,50.78%and 45.39%,respectively,while the removal rates of urea originally present in Chinese rice wine were about 60%.When the Chinese rice wine was supplemented with 108μmol/L and 500μmol/L urea,the removal rates of urea were 53.91%and 40.85%,respectively,while the removal rates of EC originally present in Chinese rice wine were about 50%.The effect of resin on the physical and chemical indexes and main flavor components of Chinese rice wine was negligible.3.The regeneration of 9-xanthydrol modified Merrifield resin was studied.The resin after being treated with EC was regenerated through alkaline hydrolysis,diazotization and hydrolysis and reduction,successively.When the weight ratio between the regenerated resin and Chinese rice wine was 1:12,the removal rate of EC and urea were 37.78%and 30.84%,respectively.4.A novel detection approach for the quantitative determination of 3-MCPD in rice wine（one kind of Chinese rice wine）and soy sauce has been established.In this process,3-MCPD was first azidated with sodium azide,and then the azidated 3-MCPD reacted with phenylethyne through click reaction,in which the product could be separated and detected by HPLC-UV.The limit of detection in this method was 0.1 mg/L,and this method had a good linearity（r²=0.999）.This process was successfully applied to the analysis of rice wine samples and soy sauce samples.The recoveries in spiking experiment in rice wine were from 94%to 104%,the relative standard deviation was from 0.51%to 2.17%.The recoveries in spiking experiment in soy sauce were from 92%to 105%,the relative standard deviation was from 1.95%to 4.74%.The results determinated by our method were consistent with GB 5009.191-2016.