The headspace volatiles produced from buffered and unbuffered cysteine model systems, containing inosine 5'-monophosphate, ribose 5-phosphate, or ribose, were examined by GC-MS. Sulfur compounds dominated the volatiles of all systems and included mercaptoketones, furanthiols, and disulfides. The inosine monophosphate systems produced much lower quantities of volatiles than ribose phosphate or ribose systems. In the systems buffered with phosphate or phthalate buffers, both ribose and ribose phosphate systems gave similar quantities of sulfur volatiles. However, in the absence of buffer, the ribose system was relatively unreactive, especially for volatiles formed via the 2,3-enolization route in the Maillard reaction, where 4-hydroxy-5-methyl-3(2H)-furanone is a key intermediate. A number of keto-enol tautomerisms, which are known to be acid-base-catalyzed, occur in the 2,3-enolization route. This may explain the catalysis of the ribose systems by the buffers. In the ribose phosphate systems, however, Maillard mechanisms probably played a less important role, because ribose 5-phosphate readily dephosphorylated to give 4-hydroxy-5-methyl-3(2H)-furanone on heating and thus provided an easier route to aroma compounds than the Maillard reaction.

BackgroundEthyl carbamate (EC) is a multi-site carcinogen in experimental animals and probably carcinogenic to humans (IARC group 2A). Traces of EC below health-relevant ranges naturally occur in several fermented foods and beverages, while higher concentrations above 1 mg/l are regularly detected in only certain spirits derived from cyanogenic plants. In Brazil this concerns the sugarcane spirit cachaça and the manioc (cassava) spirit tiquira, which both regularly exceed the national EC limit of 0.15 mg/l. This study aims to estimate human exposure in Brazil and provide a quantitative risk assessment.MethodsThe human dietary intake of EC via alcoholic beverages was estimated based on WHO alcohol consumption data in combination with own surveys and literature data. This data comprises the EC contents of the different beverage groups cachaça, tiquira, other spirits, beer, wine, and unrecorded alcohol (as defined by the WHO; including alcohol which is not captured in routine government statistics nor taxed). The risk assessment was conducted using the margin of exposure (MOE) approach with benchmark doses obtained from dose-response modelling of animal experiments. Lifetime cancer risk was calculated using the T25 dose descriptor.ResultsConsidering differences between pot-still and column-still cachaça, its average EC content would be 0.38 mg/l. Tiquira contained a considerably higher average EC content of 2.34 mg/l. The whole population exposure from all alcoholic beverages was calculated to be around 100 to 200 ng/kg bw/day, with cachaça and unrecorded alcohol as the major contributing factors. The MOE was calculated to range between 400 and 2,466, with the lifetime cancer risk at approximately 3 cases in 10,000. An even higher risk may exist for binge-drinkers of cachaça and tiquira with MOEs of up to 80 and 15, respectively.ConclusionsAccording to our risk assessment, EC poses a significant cancer risk for the alcohol-drinking population in Brazil, in addition to that of alcohol alone. Model calculations show that the implementation of the 0.15 mg/l limit for cachaça would be beneficial, including an increase of the MOE by a factor between 3 to 6. The implementation of policy measures for tiquira and unrecorded alcohol also appears to be advisable.

a b s t r a c tEthyl carbamate (EC), a known genotoxic carcinogen, was studied in 25 brands of pot still cachaças from 19 distilleries in Paraíba State, Brazil. A concentration range of 55-700 lg/l was found with most brands ($70%) exceeding the international EC limit for spirits (150 lg/l). Brand characteristics (colour, distillation [single or double], and bottle colouration) showed no consistent connection with EC levels. However, when EC levels of yellowish (cask matured) and colourless single-distiled cachaças from the same distillery were compared, the yellowish type was much more heavily contaminated. Eleven distilleries were visited and information regarding the distillation scale, kettle heating system, kettle's shape, and cooling system of the column was collected. A close connection between EC levels and cooling system was found, with the non-cooled and cooled columns dominating the brands with high (200-700 lg/l range) and low (55-100 lg/l range) contamination levels, respectively.

A aguardente de cana brasileira é uma das bebidas alcoólicas fermento-destiladas mais produzidas no mundo, porém seu consumo está basicamente restrito ao território brasileiro. Uma das razões que explicam a preferência brasileira pela aguardente de cana, ou cachaça, talvez seja histórica ou cultural, tendo em vista que o surgimento da bebida coincide com o próprio processo de colonização do Brasil, a partir da introdução da canade-açúcar entre o séculos XVI e XVII [5]. Outra razão para esta preferência pode residir no simples fato da cachaça possuir, em geral, baixo custo, o que explica a constante associação da bebida com a população de menor poder aquisitivo.Quaisquer que sejam os motivos que expliquem a preferência brasileira pela cachaça, é razoável supor que as características sensoriais da bebida, em especial o seu aroma, também exercem um papel importante nesse processo.O aroma de um alimento pode ser explicado pela ocorrência de compostos químicos cuja principal característica é a volatilidade, a qual permite que tais compostos sejam percebidos pelos receptores nasais, tanto durante a degustação do alimento (detecção retro-nasal), como pelo odor exalado a distância. Estima-se que o processo de percepção pelo olfato (aroma) é mais sensível do que pelo paladar (sabor), em fatores que variam na ordem de 10 6 a 10 9 [14]. Ao contrário do paladar, milhares de compostos voláteis podem ser detectados e diferenciados, em menor ou maior escala, pelo olfato. Isso depende de diversos fatores, dentre os quais, a estrutura química do composto volátil e a interação deste com a matriz alimentícia [4]. Tais fatores, por sua vez, são responsáveis por características importantes dos compostos, a exemplo o valor do limiar de odor (limiar de detecção ou threshold ), que pode ser definido como a concentração mínima pela qual um composto pode ser detectado pelo sentido do olfato [4].O componente volátil majoritário das bebidas alcoó-licas é o álcool etílico, ao lado do qual está presente centenas de outros compostos voláteis proporcionalmente minoritários, os quais são formados por rotas químicas ou bioquímicas, durante e após a fermentação alcoólica. Nas classes dos compostos voláteis produzidos por estas vias, incluem-se: ésteres, aldeídos, álcoois superio- ANÁLISE DOS COMPOSTOS VOLÁTEIS RESUMOOs compostos voláteis da aguardente de cana foram extraídos por meio da concentração dinâmica do headspace em armadilhas contendo Tenax-TA e analisados por cromatografia gasosa-espectrometria de massas. Cerca de 100 compostos voláteis, com número de carbonos que variavam de 5 a 18, foram detectados. Destes, 22 foram selecionados, sendo 18 ésteres, com base nas suas quantidades no extrato ou nas suas características sensoriais obtidas na literatura. Os compostos presentes em maiores quantidades foram o 3-metil-1-butanol (álcool isoamílico), 1,1-dietoxi-etano (acetaldeído dietil acetal) e os ésteres acetato de 3-metilbutila, hexanoato de etila, octanoato de etila, decanoato de etila e dodecanoato de etila. Dentre os compostos identific...

In 2009, we reported an association between low levels of ethyl carbamate (EC) in pot still cachaças from Paraíba State, Brazil, and distillation in copper pot stills equipped with cooled columns. To strengthen these observations, we extended our study to Pernambuco State and assessed 13 pot still and 20 column still cachaça brands. An EC range from <40 to 532μg/l was found; 18 brands exceeded the Brazilian limit (150μg/l), 89% of which were column still types. Mean EC concentration of pot still cachaças was very low (64μg/l), and was well below the Paraíba study (220μg/l). An on-site investigation of pot still distilleries associated with <40μg/l brands showed a connection to differences in the distillation apparatus. Maximising distillation reflux ratios in the ascending parts and minimising exposure to copper in the descending parts (through the use of stainless steel) can reduce EC, and also avoid copper contamination.

No abstract

An improved sample preparation procedure for analysis of carcinogenic ethyl carbamate (EC) in wine by GC-MS-SIM is proposed. Differences over AOAC reference procedure were: (1) use of EC-d5 as internal standard instead of less similar propyl carbamate; (2) extraction by diethyl ether instead of more toxic dichloromethane, and (3) concentration by vacuum automated parallel evaporation instead of more time and work consuming rotary evaporation. Mean recovery was 104.4%, intraday precision was 6.7% (3.4 μg L(-)(1)) and 1.7% (88.5 μg L(-)(1)), regression coefficient was 0.999 in the linear working range of 3-89 μg L(-)(1), and limits of detection and quantification were 0.4 and 1.2 μg L(-)(1). Applicability was demonstrated by analysis (in triplicate) of 5 wine samples. EC concentration ranged from 5.2 ± 0.2 to 29.4 ± 1.5 μg L(-)(1). The analytical method is selective, accurate, repeatable, linear, and has similar method performance as the reference method along with the several mentioned advantages.

Recebido em 25/9/12; aceito em 21/1/13; publicado na web em 14/5/13While in Europe vodka is mainly derived from potatoes or cereals, a large proportion of Brazilian vodka is likely obtained from sugarcane, which contains ethyl carbamate (EC) precursors. EC, in addition to several other contaminants and congeners, were investigated in 32 samples of Brazilian vodka. All samples complied with the Brazilian regulations for congeners and contaminants, having EC content below 0.01 mg/L (detection limit). These results are probably related to the processing of vodka, in particular the use of extractive and rectifying stainless steel distillation columns, which allow the production of high strength spirits with low levels of congeners and contaminants.