Research progress on the application of different controlling strategies to minimizing ethyl carbamate in grape wine

Abstract

Ethyl carbamate (EC) is a probable carcinogenic compound commonly found in fermented foods and alcoholic beverages and has been classified as a category 2A carcinogen by the International Agency for Research on Cancer (IARC).Alcoholic beverages are one of the main sources of EC intake by humans. Therefore, many countries have introduced a standard EC limit in alcoholic beverages. Wine is the second largest alcoholic beverage in the world after beer and is loved by consumers for its rich taste. However, different survey results showed that the detection rate of EC in wine was almost 100%, while the maximum content was as high as 100 μg/L, necessitating EC content regulation in wine. The existing methods for controlling the EC level in wine mainly include optimizing raw fermentation materials and processes, using genetically engineered strains, and enzymatic methods (urease or urethanase). This review focused on introducing and comparing the advantages, disadvantages, and applicability of methods for controlling EC, and proposes two possible new techniques, that is, changing the fermentation strain and exogenously adding phenolic compounds. In the future, it is hoped that the feasibility of this prospect will be verified by pilot-scale or large-scale application to provide new insight into the regulation of EC during wine production. The formation mechanism and influencing factors of EC in wine were also introduced and the analytical methods of EC were summarized.

Formation and hazard of ethyl carbamate and construction of genetically engineered Saccharomyces cerevisiae strains in Huangjiu (Chinese grain wine)

“…A significant amount of arginine remains after the fermentation of S. cerevisiae . Arginine can be metabolized to citrulline by LAB, and citrulline can be further metabolized to ornithine, NH 3 , CO 2 , and adenosine triphosphate through ADI pathway (Deng et al., 2023; Yu et al., 2020; Zhou, Patrignani, et al., 2021). Three enzymes, namely, ADIase, ornithine transcarbamylase (OTCase), and carbamate kinase, catalyze the decomposition of l ‐arginine (Gowd et al., 2018; Zhou, Shu, et al., 2021).…”

“…Urea is mainly produced by S. cerevisiae due to the arginine catabolism in the process of Huangjiu fermentation (Dong et al., 2022; Ruiz‐Muñoz et al., 2023; Wu et al., 2016). As illustrated in Figure 5, extracellular arginine is transferred to cytoplasm and further catalyzed and catabolized into urea and ornithine by arginase ( CAR1 gene) in S. cerevisiae cells (Chin et al., 2016; Deng et al., 2023; Gowd et al., 2018; Lou et al., 2022; Ruiz‐Muñoz et al., 2023). Ornithine and carbamoyl phosphate synthesize citrulline under the action of OTCase (encoded by ARG3 ).…”

“…Following arginine metabolism, the degradation of urea may not always occur immediately. S. cerevisiae possesses two urea transporter proteins (Dur3p and Dur4p), encoded by the DUR3 and DUR4 genes, on its cell membrane (Deng et al., 2023; Guo et al., 2016; Ruiz‐Muñoz et al., 2023). Increased intracellular urea concentration heightens the toxicity of S. cerevisiae cells.…”

“…Although approximately 5% of EC is directly excreted in urine without undergoing metabolism, the majority of EC has clearly proposed three metabolic pathways in vivo (Deng et al., 2023; Gowd et al., 2018). The first pathway involves nontoxic hydrolysis: More than 90% of EC is metabolized into ethanol, CO 2 , and NH 3 by liver esterase (Chen, Zeng, Fang, et al., 2022; Deng et al., 2023; Gowd et al., 2018). The second pathway is side chain oxidation: About 0.5% of EC is oxidized by cytochrome P450, resulting in producing vinyl carbamate, which will then be further oxidized to vinyl carbamate epoxide (Deng et al., 2023; Gowd et al., 2018; Tu et al., 2018; Wang, Chen, & Xu, 2021; Wang, Chen, Wu, et al., 2021).…”

“…Therefore, the application of the two enzymes has been widely limited. In addition to established EC mitigation strategies, experimental methods to reduce EC formation using genetic engineering are being developed (Deng et al., 2023). S. cerevisiae is the primary urea producer, and suppressing the urea formation in S. cerevisiae or improving the metabolic capacity of urea through genetic engineering offers a novel approach to control the formation of EC in Huangjiu .…”