Effect of cultures of synthetic starters on the flavour and ethyl carbamate content of rice wine

Abstract

Ethyl carbamate (EC) concentration is an important indicator of the safety of rice wine. In this study, the effects of replacing traditional starters with synthetic starters on the quality of rice wine were studied to provide a basis for the application of laboratory strains to explore the metabolic basis of EC formation in rice wine fermentation systems. The effects of synthetic starters on the physicochemical indices, free amino acids, flavour compounds, urea and EC of rice wine were studied. The results showed that the microorganism species and inoculation fermentation method strongly influenced the physicochemical and flavour properties of the rice wine, among which continuous co-fermentation improved the mellowness and flavour of the rice wine. The concentrations of urea and EC in rice wine fermented with synthetic starters decreased significantly compared with those in the control group, in which the urea content decreased by up to 97.4% and the EC content decreased by up to 90.9%. In addition, the flavour compound data showed that the differences in the aromas of rice wine fermented with different starters were mainly due to the differences in the contents of alcohols and esters. These findings suggest that EC can be regulated by changes in starters and provide guidance for the optimal configuration of mixed fermentation systems.