Study On Reduction Measures Of Ethyl Carbamate In Chinese Rice Wine

Ethyl carbamate(EC)is a potential carcinogen and exists in many fermented foods.Among various alcoholic beverages in China,the ethyl carbamate problem that Chinese rice wine faces is more prominent,posing a threat to the health of consumers,while seriously hindering the development of Chinese rice wine industry.Therefore,it is important to effectively reduce the content of ethyl carbamate in Chinese rice wine for the food safety and development of Chinese rice wine industry.In this paper,an integrated strategy for the reduction of the precursor urea and terminal EC removal was established,which significantly reduces the EC content in Chinese rice wine.In this paper,firstly,the immobilization of neutral urease was studied to improve its tolerance in Chinese rice wine;and further studied the process conditions to reduce the urea content in Chinese rice wine using the composite immobilized urease;finally,the adsorption conditions were optimized to remove EC directly.The main results are shown as follows:(1)The optimal immobilization conditions of neutral urease were optimized:chitosan concentration 2%,DEAE cellulose concentration 3%,glutaraldehyde concentration 0.05%,cross-linking time 40 min,immobilization time 8 h,urease addition amount 11 U / g.The acid resistance of immobilized neutral urease was significantly increased.The relative enzyme activity increased from 11.75% ~ 48.32%to 61.72% ~ 92.91% in pH4 ~ 5,and the stability was good.(2)The optimal conditions of the composite immobilized urease reducing the urea content in Chinese rice wine were optimized: rice wine pH4.8,synergistic temperature40 ?,the composite immobilized urease addition amount 1.6 U / mL,processing time2 h.Under the optimum conditions,the urea removal rate was 94.12%(the initial urea content was 40 mg / L).The reusability of the composite immobilized urease was good.After the composite immobilized urease was reused five times,the urea removal rate of Chinese rice wine which pH ranged from 4.0 to 4.8 were more than 70%.(3)The resin materials DM301 and DA-201 with better effect of EC adsorption and low impact on the flavor of rice wine were screened out.And the combination of the two could be complementary to each other,which could further reduce the loss of flavor substances.The optimal conditions for the adsorption removal of EC were as follows: the amount of compound resin wet weight 10 g(per 100 mL of rice wine),temperature 30 ?,adsorption time 48 h.Under this process conditions,the EC removal rate of Chinese rice wine(EC initial concentration 276.11 ?g / L)was76.81%.