Ethyl carbamate in the production and aging of cachaça in oak (Quercus sp.) and amburana (Amburana cearensis) barrels

There are residual organic and inorganic contaminants in the cachaça production chain. Among the organic contaminants, ethyl carbamate has been widely studied. It is formed naturally during the fermentation processes and can be found in many foods and beverages such as bread, yoghurt, wine, beer and especially in fermented–distilled beverages such as whiskey, rum, vodka, grappa, cachaça and tiquira. The objective of this study was to identify and quantify ethyl carbamate during the steps of the production process and aging of cachaça in oak (Quercus sp) and amburana (Amburana cearensis) barrels. The cane used for cachaça production, as well as the process for obtaining the fermentation broth, did not affect the formation of ethyl carbamate, as it was not detected. Carbamate was detected in low concentrations, but was not quantified, in the fermentation, distillation and aging steps. Copyright © 2014 The Institute of Brewing & Distilling     

Determination of ethyl carbamate in cachaça stored in newly made oak,amburana, jatobá, balsa and peroba vats and in glass containers

Ethyl carbamate was quantified in cachaça using high‐performance liquid chromatography with fluorescence detection during the production process and during storage in different types of wooden casks and glass containers, with and without the presence of light. According to the physicochemical analysis, the head and tail fractions are unacceptable for consumption. Ethyl carbamate was detected in sugarcane juice and during fermentation. During distillation, ethyl carbamate levels ranged from the limit of detection to 17.1 μg L⁻¹. Ethyl carbamate increased during storage in wooden casks. The presence (or absence) of light did not affect the formation of ethyl carbamate in cachaça stored in glass containers. Copyright © 2017 The Institute of Brewing & Distilling     

Ethyl carbamate kinetics in double distillation of sugar cane spirit. Part 2: influence of type of pot still

This study aimed to assess the influence of the pot still configuration on the reduction of ethyl carbamate content in double‐distilled sugar cane spirit, as well as to describe the effects of double distillation on this reduction. Ethyl carbamate is a potentially carcinogenic compound that may be present in high concentrations in sugar cane spirit, and therefore could become a public health problem, as well as a factor hindering Brazilian exports of this beverage. In sugar cane spirit production in Brazil, neither pot still configuration nor distillate reflux and cooling/condensation systems are standardized. In this study, ethanol, copper and ethyl carbamate contents were assessed (GC‐MS) in sugar cane spirits that were double‐distilled in pot stills with different reflux and cooling systems. Double distillation removed 94–98.5% of ethyl carbamate from sugar cane spirit. Pot stills with high reflux rates (equipped with dephlegmator or rectifying system) were more effective in reducing the ethyl carbamate content in double‐distilled sugar cane spirit. Copyright © 2013 The Institute of Brewing & Distilling     

Ethyl carbamate kinetics in double distillation of sugar cane spirit

The aim of this study was to verify the effect of a double distillation on the reduction of the ethyl carbamate content in sugar cane spirit. Ethyl carbamate is a potentially carcinogenic compound normally present at critical levels in sugar cane spirit, constituting a public health problem and therefore hindering the export of this beverage. The ethanol, copper and ethyl carbamate contents were evaluated, using gas chromatography/mass spectroscopy, during a double distillation of the fermented sugar cane juice. The distillate fraction from the first distillation accumulated 30% of the ethyl carbamate formed. In the second distillation, the ethyl carbamate and the copper content increased during the process as the alcohol content decreased, and only 3% of the ethyl carbamate formed was collected in the spirit. Double distillation decreased the ethyl carbamate content in the sugar cane spirit by 97%. Copyright © 2012 The Institute of Brewing & Distilling     

Quantification of ethyl carbamate in cachaça produced in different agro‐industrial production systems

Popularly known by various names such as caninha, dangerous, drips, damned and many other denominations, cachaça is the genuine Brazilian drink, produced by the fermentation of sugarcane juice by yeast, followed by distillation in alambics. Considering that cachaça is the most widely consumed distilled beverage from Brazil, the knowledge of the chemical composition and the presence of potentially toxic compounds such as ethyl carbamate, considered a human carcinogen, is important. The aim of this study was to evaluate the influence of different conditions of the agro‐industrial cachaça production systems, including the variety of sugarcane, on the quantification of ethyl carbamate through the chromatographic. Thirteen unaged beverage samples, produced from different varieties of sugarcane, were analysed. Using analysis of variance and comparison of average concentrations of ethyl carbamate (Scott–Knott, α = 5%), all of the samples were found to contain contaminant levels below the ceiling established by the legislation, which is 210 µg L^?1. Copyright © 2016 The Institute of Brewing & Distilling     

Effect of co-inoculation of Saccharomyces cerevisiae and Lactobacillus fermentum on the quality of the distilled sugar cane beverage cachaça

Abstract: The effect of Lactobacillus fermentum in co‐inoculation with Saccharomyces cerevisiae UFLA CA11 on the quality of cachaça (sugar cane spirit) was evaluated. The co‐inoculation was first evaluated in flask fermentation, and subsequently, yeast and bacteria were co‐cultured at approximately 10⁵ CFU/mL and 10⁸ CFU/mL, respectively, in 4 consecutive batches. L. fermentum did not affect the growth or activity (sugar consumption and fermentation rate) of S. cerevisiae UFLA CA11 during fermentation. The physicochemical analysis revealed a higher concentration (Tukey test) of aldehydes (22.07 mg/100 mL anhydrous alcohol) in cachaça produced by co‐inoculation. Analysis of volatile compounds using GC‐FID demonstrated that cachaça produced by co‐inoculation had higher concentrations of acetaldehyde (25.15 mg/L), ethyl acetate (30.17 mg/L), and 2,3‐butanedione (170.39 μ/L), while cachaça produced by UFLA CA11 contained higher concentrations of ethyl lactate (1205.98 μ/L), propionic acid (127.97 μ/L), butyric acid (2335.57 μ/L), and 1‐pentanol (469.23 μ/L). The lowest concentration of acetic acid measured by HPLC was found in cachaça obtained with UFLA CA11. The sensory analysis, performed using the Mann–Whitney test, revealed that cachaça produced by co‐inoculation differed from that produced by UFLA CA11 in taste and aroma. Practical Application: This study reports on the use of a mixed culture of Saccharomyces cerevisae and Lactobacillus fermentum to produce cachaça and shows the influence of co‐inoculation of yeast and bacteria on the quality of this beverage.     

Determination of ethyl carbamate in cachaças produced by selected yeast and spontaneous fermentation

Cachaça is a beverage produced by the distillation of fermented must from sugarcane. During the manufacturing steps, producers commonly use naturally occurring yeasts in the preparation of the fermentation broth, resulting in spontaneous fermentation. The composition of the resulting beverages can vary greatly, especially if various species and strains of yeast are present. The beverages produced with selected yeast strains are an alternative, leading to the production of more standardized beverages. Ethyl carbamate, which is highly toxic and has carcinogenic potential, is among the possible contaminants. The objectives of this study were to determine the levels of ethyl carbamate in cachaça produced by different types of fermentation and follow its formation during the production stages. The cachaças that contained rice bran as a nutrient during the fermentation stage contained the highest levels of ethyl carbamate throughout the production process and storage. Copyright © 2016 The Institute of Brewing & Distilling     

Production of sensory compounds by means of the yeast Dekkera bruxellensis in different nitrogen sources with the prospect of producing cachaça

The distilled spirit made from sugar cane juice, also known as cachaça, is a traditional Brazilian beverage that in recent years has increased its market share among international distilled beverages. Several volatile compounds produced by yeast cells during the fermentation process are responsible for the unique taste and aroma of this drink. The yeast Dekkera bruxellensis has acquired increasing importance in the fermented beverage production, as the different metabolites produced by this yeast may be either beneficial or harmful to the end‐product. Since D. bruxellensis is often found in the fermentation processes carried out in ethanol fuel distillation in Brazil, we employed this yeast to analyse the physiological profile and production of aromatic compounds and to examine whether it is feasible to regard it as a cachaça‐producing microorganism. The assays were performed on a small scale and simulated the conditions for the production of handmade cachaça. The results showed that the presence of aromatic and branched‐chain amino acids in the medium has a strong influence on the metabolism and production of flavours by D. bruxellensis. The assimilation of these alternative nitrogen sources led to different fermentation yields and the production of flavouring compounds. The influence of the nitrogen source on the metabolism of fusel alcohols and esters in D. bruxellensis highlights the need for further studies of the nitrogen requirements to obtain the desired level of sensory compounds in the fermentation. Our results suggest that D. bruxellensis has the potential to play a role in the production of cachaça. Copyright © 2014 John Wiley & Sons, Ltd.     

Influence of fast and slow distillation on ethyl carbamate content and on coefficient of non‐alcohol components in Brazilian sugarcane spirits

Ethyl carbamate is an impurity present in distilled beverages. Given the risk of it being a carcinogenic substance, Brazilian legislation has determined that its presence in distilled beverages, such as ‘aguardente’ and ‘cachaça’ (two types of sugarcane spirits), should be limited to a maximum of 150 µg/L. Ordinary spirits usually contain variable amounts of ethyl carbamate, although in lower concentrations than the maximum determined by law. The finding that commercial spirits had a much lower concentration of this impurity (around 50 µg/L) led the authors to research the reasons for the differences, and these are explored in this paper, with a focus on the speed of the distillation process and its influence on the spirit's composition. The team conducted research in a sugarcane distillery producing ‘aguardente’ using a simple pot still and measured the influence of fast and slow distillation on the presence of ethyl carbamate and non‐alcohol components in the process. The results demonstrated that the speed of distillation was proportionally related to the concentration of ethyl carbamate and secondary components in the beverage's composition. Copyright © 2012 The Institute of Brewing & Distilling     

Membrane processing of the Brazilian spirit Cachaça

As an alternative technology for the production of cachaça, fermented sugar cane must was clarified by ceramic α‐alumina membranes, followed by water removal by pervaporation using a silk sericin/polyvinylalcohol (PVA) non‐porous membrane. The high solute content in the fermented must resulted in fouling and concentration polarisation in both microfiltration and pervaporation. The hydrophilicity of the sericin/PVA blends was exploited in ethanol and aroma concentration, at an optimal temperature of 20°C, resulting in a separation factor and permeation flux of 3.7 and 958.3 g/m² h. An aroma profile was performed using GC SPME/headspace and GC‐MS, analysing the content of ethanol, 3‐methyl‐1‐butanol, 2‐methyl‐1‐butanol, ethyl lactate, isoamyl acetate, ethyl octanoate and ethyl laurate. The results show that the volatiles present in the fermented sugar cane must were concentrated, with recoveries of 93.9 and 94.3% of the principal aromatic compounds. © 2019 The Institute of Brewing & Distilling     

Formation of volatile and maturation‐related congeners during the aging of sugarcane spirit in oak barrels

The aging process of distilled spirits is a complex system based on the extraction of molecules from the wood and interactions with the liquid, the phenomenon of migration of wood constituents, as well as the formation and degradation of several compounds. Volatile and maturation‐related congeners were evaluated during the aging process of cachaça, a Brazilian sugarcane spirit aged in oak barrels. Aged cachaça presented alterations in the levels of ethanol, higher alcohols, acetaldehyde, volatile acidity, ethyl acetate, total volatile congeners, isoamyl alcohol, ethyl carbamate and copper. The aging markers (gallic acid, furfural, 5‐hydroxymethylfurfural, vanillic acid, syringic acid, vanillin, syringaldehyde, sinapaldehyde and coniferaldehyde) were compared with the compounds found in whisky, cognac, armagnac, bourbon and brandy. Monitoring the generation and evolution of congeners during the aging process allowed the characterization of cachaça and the identification of product maturity. Copyright © 2014 The Institute of Brewing & Distilling     

The effect of distillation conditions and alcohol content in ‘heart’ fractions on the concentration of aroma volatiles and undesirable compounds in plum brandies

This study investigates the effect of double‐ or single‐stage distillation and different alcohol content in ‘hearts’ (middle fractions) on the distribution of aroma volatiles and undesirable compounds (methanol, hydrocyanic acid, ethyl carbamate) during distillation of plum brandies. Irrespective of the distillation method used, the first fractions (‘heads’) included mainly aliphatic aldehydes, acetals and esters as well as higher alcohols (1‐propanol, 2‐methyl‐1‐propanol, 1‐butanol, 2‐methyl‐1‐butanol and 3‐methyl‐1‐butanol). Furfural, 1‐hexanol, benzyl alcohol, 2‐phenylethanol and ethyl carbamate occurred in relatively high concentrations in the ‘tail’ fractions. Increasing the concentration of alcohol in the heart fractions from 70 to 90% v /v resulted in a gradual decrease in the concentration of all detected volatile compounds. Compared with single‐stage distillation, double distillation produced heart fractions with lower concentration of acetaldehyde and benzaldehyde and with higher contents of furfural and esters, such as isobutyl acetate and isoamyl acetate. There was a statistically significant increase in the amounts of methanol and ethyl carbamate obtained from double distillation compared with similar fractions derived from the single‐stage process. However, in all fractions these compounds occurred in concentrations much lower than the limits specified by EU regulations. The heart fraction from the double‐stage process with 83% v /v alcohol content received the best scores for aroma and flavour. Copyright © 2017 The Institute of Brewing & Distilling     

Effect of light on the concentration of ethyl carbamate in cachaça stored in glass bottles

This study sought to evaluate the influence of natural light on the concentration of ethyl carbamate (EC) in cachaças aged in wooden barrels and stored in glass bottles for a period of 6 months. The quantification of EC was achieved by HPLC using a fluorescence detector after previous derivation of the samples and standards with 9‐xanthydrol. All of the samples presented an EC concentration below the limit established by Brazilian legislation. The highest concentration found was 79.70 µg L^?1. As for the influence of light and storage period, 70% of the samples exhibited an influence of these parameters. Copyright © 2015 The Institute of Brewing & Distilling     

Behaviour of some volatile compounds during distillation of fermented marc exposed to the smoking process

Fermented marc was exposed to a controlled smoking process for 120, 240 and 460 min before distillation. To improve insight into the behaviour of ethanol and the partitioning of some volatile compounds, each distillate was collected in fractions (ethanol content from 24 to 59% vol) and analysed for the higher alcohols (2‐butanol, n‐butanol, n‐propanol, isoamyl alcohols, n‐hexanol) ethyl esters (ethyl acetate, ethyl lactate, ethyl caproate, ethyl caprylate, ethyl caprate, ethyl myristate and ethyl laurate) and volatile phenols (guaiacol, methyl guaiacol, ethyl guaiacol, propyl guaiacol, eugenol and isoeugenol). The results obtained showed that the behaviour of ethanol was not regular and the alcohol strength was lower when the smoking process was applied to fermented marc. The volatile phenols highlighted a distillation behaviour characterised by an increase in concentration at the end of the distillation process when ethanol decreased. Long time exposure of the marc to the smoking process resulted in higher reduction of ethanol, higher alcohols and ethyl esters. Instead, the volatile phenols increased with the duration of the smoking process.     

Physicochemical profile and determination of volatile compounds in cachaça stored in new oak (Quercus sp.), amburana (Amburana cearensis), jatoba (Hymenaeae carbouril), balsam (Myroxylon peruiferum) and peroba (Paratecoma peroba) casks by SPME‐GC–MS

Aging has become common practice among producers seeking to increase the value of their products. The objective of this work was to conduct periodic monitoring by solid‐phase microextraction–gas chromatography–mass spectrometry of the physical and chemical quality of aging cachaça in terms of the alcohol content, volatile acidity, esters, aldehydes, higher alcohols, furfural, methanol, dry extract, copper and volatile compounds in the production process (distilled fractions) and during storage in casks newly made from oak (Quercus sp.), amburana (Amburana cearensis), jatoba (Hymenaeae carbouril), balsam (Myroxylon peruiferum) and peroba (Paratecoma peroba). The barrels were made in a specialized cooperage, and cachaça was obtained from a production unit in the southern region of Minas Gerais. Distinct physicochemical values were obtained for the distilled fractions; head and tail fractions had inappropriate concentrations of alcohol, aldehydes and butan‐1‐ol. Values within the limits established by law were obtained for the heart fraction, both in the distillation process and during aging, and it is, therefore, suitable for consumption. Several important compounds responsible for the aroma and flavour of the cachaças were observed, and alcohols, acids, esters and sesquiterpenes were found to compose the main groups. Through variance and main component analysis, important chemical changes were observed in the beverages. Copyright © 2016 The Institute of Brewing & Distilling     

甘蔗醋及果醋饮料的生产工艺研究

以甘蔗汁为原料,探索了液态发酵甘蔗果醋的生产工艺条件和甘蔗果醋饮料研制方法。通过单因素和正交试验,优化了工艺条件和配方。结果表明,酒精发酵的工艺参数为温度30 ℃、初始pH值为4.5、接种量12%、发酵时间6 d。醋酸发酵最佳工艺条件为酒精度8%vol、糖度7 °Bx、pH值为5.0、接种量10%。在控制温度32 ℃、转速150 r/min条件下发酵7 d得到平均酸度约6.37 g/100 mL、残糖4.2 g/100 mL甘蔗果醋。甘蔗果醋饮料最佳配方为甘蔗原醋15%、鲜甘蔗汁40%、蔗糖2%、柠檬酸0.14%、DL-苹果酸0.05%。     

GC‐MS analysis of ethyl carbamate in distilled sugar cane spirits from the northern and southern regions of Minas Gerais

Ethyl carbamate, also known as urethane, is the ethyl ester of carbamic acid. Animal studies with this compound have demonstrated its carcinogenic potential. In this study, gas chromatography coupled to mass spectrometry (GC‐MS) was applied for the determination of ethyl carbamate in sugar cane spirits in the northern and southern regions of the state of Minas Gerais in Brazil. The samples were collected from distillates from small‐ and medium‐scale stills. The concentrations determined for ethyl carbamate in the samples ranged from 23 to 980 µg L^?1. All of the samples analysed from the southern region of Minas Gerais had an ethyl carbamate content below the limit set by the Brazilian legislation for ethyl carbamate of 150 µg L^?1, while a number of samples from northern Minas Gerais exceeded this limit. No correlations were observed between the levels of ethyl carbamate and the alcohol content, acidity or copper concentrations in the samples. Copyright © 2014 The Institute of Brewing & Distilling     

氨基酸与葡萄酒中氨基甲酸乙酯的关系研究

氨基甲酸乙酯是发酵食品中广泛存在的"2A"类致癌物,可由氨甲酰化合物和乙醇反应生成。葡萄汁中的氨基酸经酿酒酵母的氮代谢后,可生成氨甲酰化合物,进而形成氨基甲酸乙酯。为了研究氨基酸与葡萄酒中氨基甲酸乙酯的关系,本文构建了氨基酸缺失的模拟葡萄汁,比较了他们和正常模拟葡萄汁经主发酵后的氨基甲酸乙酯和尿素含量,并采用N15同位素示踪确认了氨基酸对氨基甲酸乙酯的贡献。结果表明:磷酸氢二铵单独作为氮源发酵不会产生氨基甲酸乙酯,用其替代缺失的氨基酸不会影响正常发酵过程;缺失精氨酸的模拟葡萄汁发酵后,尿素和氨基甲酸乙酯含量明显减少,而缺失其它氨基酸对二者无显著影响。N15同位素示踪证明精氨酸胍基的氮原子参与了氨基甲酸乙酯的合成。本文为发酵食品危害物的前体挖掘提供了新的思路,也为气质联用仪辨识同位素提供了方法借鉴。