Regulation of ethyl carbamate during Huangjiu fermentation and quality changes by Btn2p

Ethyl carbamate (EC), a potential carcinogen, is spontaneously formed from urea and ethanol during Huangjiu fermentation, and urea is derived from arginine (Arg) degradation by Saccharomyces cerevisiae . Previous studies have shown that BTN2 influences Arg uptake and metabolism. In this study, we conducted a comprehensive analysis of the variation of EC, major metabolites, enzyme activities, volatile flavor compounds, amino acids, and general quality within the Arg metabolism pathway during Huangjiu fermentation by wild type, BTN2 Δ, and BTN2 ↑ strains. The results indicated that BTN2 knock out significantly reduced EC, urea, and citrulline by 12.28, 15.6, and 20.18%, respectively. Furthermore, flavors and amino acids among the three groups exhibited minimal variation, resulting in insignificant differences in the sensory evaluation. The primary flavors identified were ethyl lactate and isoamyl alcohol. Cysteine, Arg, and glutamine contributed significantly to the overall flavor profile. These findings suggest that Btn2p is a potential target for the reduction of EC.