Ethyl Carbamate (ethyl + carbamate)

Distribution by Scientific Domains

Selected Abstracts

Functional enhancement of Sake yeast strains to minimize the production of ethyl carbamate in Sake wine

M.S. Dahabieh
Abstract Aims:, In fermented alcoholic beverages and particularly in Japanese Sake wine, the ubiquitous presence of the probable human carcinogen ethyl carbamate (EC) is a topic of significant concern. This study aims to develop novel methods for the reduction of EC in Sake wine. Methods and Results:, To reduce the high levels of EC in Sake wine, urea-degrading and urea-importing yeast strains were created by integrating linear cassettes containing either the respective DUR1,2 or DUR3 genes, under the control of the constitutively active Saccharomyces cerevisiae PGK1 promoter, into the Sake yeast strains K7 and K9. The self-cloned, urea-degrading Sake strains K7DUR1,2 and K9DUR1,2 produced Sake wine with 87 and 68% less EC, respectively, while the urea-importing Sake yeast strain K7DUR3 reduced EC by 15%. All functionally enhanced yeast strains were shown to be substantially equivalent to their parental strains in terms of fermentation rate, ethanol production, phenotype and transcriptome. Conclusions:, Under the conditions tested, urea-degrading yeast (constitutive DUR1,2 expression) are superior to urea-importing yeast (constitutive DUR3 expression) for EC reduction in Sake wine, and constitutive co-expression of DUR1,2 and DUR3 does not yield synergistic EC reduction. Significance and Impact of the Study:, The self-cloned, substantially equivalent, urea-degrading Sake yeast strains K7DUR1,2 and K9DUR1,2, which contain the integrated DUR1,2 cassette, are capable of highly efficacious EC reduction during Sake brewing trials, are suitable for commercialization and are important tools for modern Sake makers in their efforts to reduce high EC levels in Sake wine. [source]

The role of GAP1 gene in the nitrogen metabolism of Saccharomyces cerevisiae during wine fermentation

R. Chiva
Abstract Aim:, The aim of this study was to analyse the relevance of the general amino acid permease gene (GAP1) of the wine yeast Saccharomyces cerevisiae on nitrogen metabolism and fermentation performance. Methods and Results:, We constructed a gap1 mutant in a wine strain. We compared fermentation rate, biomass production and nitrogen consumption between the gap1 mutant and its parental strain during fermentations with different nitrogen concentrations. The fermentation capacity of the gap1 mutant strain was impaired in the nitrogen-limited and -excessive conditions. The nitrogen consumption rate between the wild strain and the mutant was different for some amino acids, especially those affected by nitrogen catabolite repression (NCR). The deletion of GAP1 gene also modified the gene expression of other permeases. Conclusions:, The Gap1 permease seems to be important during wine fermentations with low and high nitrogen content, not only because of its amino acid transporter role but also because of its function as an amino acid sensor. Significance and Impact of the Study:, A possible biotechnological advantage of a gap1 mutant is its scarce consumption of arginine, whose metabolism has been related to the production of the carcinogenic ethyl carbamate. [source]

Kinetics of the arginine metabolism of malolactic wine lactic acid bacteria Lactobacillus buchneri CUC-3 and Oenococcus oeni Lo111

R. Mira de Orduña
The excretion of citrulline, a precursor of carcinogenic ethyl carbamate, formed from arginine degradation by malolactic bacteria in wine is of toxicological concern. The arginine metabolism of resting cells of Lactobacillus buchneri CUC-3 and Oenococcus oeni Lo111 was examined. The citrulline excretion rate was found to be linearly correlated to the arginine degradation rate. It was possible to calculate an arginine to citrulline conversion ratio which could be used to predict the amount of citrulline expected after the degradation of a known quantity of arginine. The conversion ratios determined in this study were similar to data calculated from other authors for fermentations in wine and ranged between 4·0% and 7·7%. Ribose, fructose and glucose inhibited the degradation of arginine in Lact. buchneri CUC-3, and inhibition of arginine degradation by glucose correlated with higher arginine to citrulline conversion ratios. The work presents new results of arginine metabolism in malolactic bacteria and gives starting points for investigations in wine. [source]

Association Between Quality of Cheap and Unrecorded Alcohol Products and Public Health Consequences in Poland

ALCOHOLISM, Issue 10 2009
Dirk W. Lachenmeier
Background:, The research aimed to study the quality of cheap alcohol products in Poland. These included unrecorded alcohols (i.e., home-produced or illegally imported), estimated to constitute more than 25% of total consumption and fruit wines. Methods:, A sample of alcohol products (n = 52) was collected from local markets and chemical analyses were conducted. The parameters studied were alcoholic strength, volatiles (methanol, acetaldehyde, and higher alcohols), ethyl carbamate, inorganic elements, and food additives including preservatives, colors, and sweeteners. The compositions of the beverages were then toxicologically evaluated using international standards. Results:, With the exception of 1 fortified wine, the unrecorded alcohols were home-produced fruit-derived spirits (moonshine) and spirits imported from other countries. We did not detect any nonbeverage surrogate alcohol. The unrecorded spirits contained, on average, 45% vol of alcohol. However, some products with considerably higher alcoholic strengths were found (up to 85% vol) with no labeling of the content on the bottles. These products may cause more pronounced detrimental health effects (e.g., liver cirrhosis, injuries, some forms of malignant neoplasms, alcohol use disorders, and cardiovascular disease) than will commercial beverages, especially as the consumer may be unaware of the alcohol content consumed. Fruit wines containing between 9.5 and 12.2% vol alcohol showed problems in terms of their additive content and their labeling (e.g., sulfites, sorbic acid, saccharin, and artificial colors) and should be subjected to stricter control. Regarding the other components investigated, the suspected human carcinogens, acetaldehyde and ethyl carbamate, were found at levels relevant to public health concerns. While acetaldehyde is a typical constituent of fermented beverages, ethyl carbamate was found only in home-produced unrecorded alcohols derived from stone fruits with levels significantly above international guidelines. Conclusions:, The contamination of unrecorded alcohols with ethyl carbamate should be analyzed in a larger sample that also should include legal alcoholic beverages. Furthermore, the impacts of unrecorded alcohol on the health of people with lower socioeconomic status should be studied in detail. Overall, given the extent of the alcohol-attributable disease burden in Poland, the highest priority should be given to the problem of ethanol and its very high content in unrecorded alcohol products. [source]

The determination of urea in wine , a review

Abstract The concentration of urea in wine is not routinely measured in Australian laboratories, but has been examined in studies of yeast metabolism and the formation of ethyl carbamate, a known carcinogen. For alcoholic beverages that may contain high levels of urea, steps have been taken to reduce the concentration of urea and therefore prevent ethyl carbamate production. Methods for the determination of urea in wine can be grouped into three categories that indicate how selectivity for urea is achieved; those based on colour-forming reactions, enzymatic hydrolysis and chromatographic separation. The two dominant methods used by research groups over the past fifteen years for the determination of urea in wine are based on the urea/ammonia test kit available from Boeringer Mannheim/R-Biopharm and the reaction of urea with 1-phenyl-1,2-propanedione-2-oxime; both are time-consuming and labour-intensive, but involve relatively straightforward and well-established procedures. However, other options are available that may be better suited to the desired application and the instrumentation available in any particular laboratory. [source]

Synthesis and Stability in Biological Media of 1H -Imidazole-1-carboxylates of ROS203, an Antagonist of the Histamine H3 Receptor

Mirko Rivara
Abstract A series of carbamate derivatives of the H3 antagonist ROS203 (1) were prepared, and their lipophilicity and steric hindrance were modulated by introducing linear or branched alkyl chains of various lengths. In vitro stability studies were conducted to evaluate how structural modulations affect the intrinsic reactivity of the carbamoyl moiety and its recognition by metabolic enzymes. Linear alkyl carbamates were the most susceptible to enzymatic hydrolysis, with bioconversion rates being higher in rat liver and plasma. Chain ramification significantly enhanced the enzymatic stability of the set, with two derivatives (1g and 1h) being more stable by a factor of 8,40 than the ethyl carbamate 1a. Incubation with bovine serum albumin (BSA) showed a protective role of proteins on chemical and porcine-liver esterase (PLE)-catalyzed hydrolysis. Ex vivo binding data after i.v. administration of 1h revealed prolonged displacement of the labeled ligand [3H]-(R)- , -methylhistamine ([3H]RAMHA) from rat-brain cortical membranes, when compared to 1. However, the high rates of bioconversion in liver, as well as the chemical instability of 1h, suggest that further work is needed to optimize the enzymatic and chemical stability of these compounds. [source]


Wei Zhang
SUMMARY 1In coronary artery disease, the typical atheromatous plaque consists of a lipid core containing various inflammatory cells and a fibrous cap composed mostly of extracellular matrix. Both matrix metalloproteinases (MMPs) and inflammation are involved in the initiation of atherosclerotic plaques and plaque instability. 22,3,4¢,5-Tetrahydroxystilbene-2- O -b- d -glucoside (TSG) reduces the blood lipid content and prevents the atherosclerotic process, but the mechanism of action of TSG is unclear. The purpose of the present study was to test whether TSG can suppress MMP activation and inflammation in atherosclerotic rats. 3Sixty male Sprague-Dawley rats were randomly divided into six groups. Atherosclerosis was induced by feeding rats a hyperlipidaemic diet; TSG (120, 60 or 30 mg/kg per day) was administered by oral gavage. After 12 weeks of treatment, rats were killed (ethyl carbamate 1200 mg/kg) and serum lipids, C-reactive protein (CRP), interleukin (IL)-6 and tumour necrosis factor (TNF)-a were measured. Haematoxylin,eosin (H&E) staining was used to examine histopathological changes in the aorta. The mRNA and protein expression of MMPs were assayed by reverse transcription,polymerase chain reaction, immunohistochemistry and western blotting. Simvastatin (2 mg/kg per day) was administered as a positive control, whereas the vehicle (0.9% NaCl) group served as the untreated control. 4In the present study, TSG significantly and dose-dependently attenuated the hyperlipidaemic diet-induced alterations in serum lipid profile and increases in CRP, IL-6 and TNF-a levels. In addition, TSG normalized the structure of the aortic wall and suppressed the expression of MMP-2 and MMP-9 at both the mRNA and protein level in the rat aortic wall. 5In summary, TSG suppresses the expression of MMP-2 and MMP-9 and inhibits inflammation in the diet-induced atherosclerotic rats. [source]