The Impact of Different Concentrations of Raspberry Extract on the Ethyl Carbamate Content in Chinese Rice Wine

This study explores the regulatory effects of raspberry extract (RBE) as a natural inhibitor on the ethyl carbamate (EC) formation during the fermentation of Chinese rice wine (CRW) and assesses its impact on the wine's quality. We incorporated varying concentrations of RBE (250, 500, and 1000 mg·L^-1) into both the fermentation mash of CRW and a simulated fermentation system. Systematic monitoring included the EC content, levels of precursors (urea, arginine, citrulline), activities of key enzymes (ADIase, OTCase, arginase, urease), and the impact of RBE on relevant genes' transcriptional levels. The study was further complemented by transcriptome sequencing. The molecular regulation mechanism of RBE on Saccharomyces cerevisiae's metabolic processes was analyzed. We found that 500 mg·L^-1 RBE notably reduced EC production and inhibited urea accumulation while also affecting citrulline metabolism by regulating the activities of the ADIase and OTCase enzymes. Transcriptome analysis revealed the extensive impact of RBE on gene expression in S. cerevisiae. Additionally, when the concentration of RBE was 500 mg·L^-1 or higher, it notably influenced the volatile aroma and free amino acid content of the resulting wine, thereby enriching its flavor. This study systematically elucidates the inhibitory effect on EC production and the multifaceted impacts of RBE in CRW fermentation, providing a novel natural inhibitor for the prevention and control of EC in fermented products and laying the groundwork for understanding the mechanism by which RBE inhibits EC formation.