, 2004). Faria (2003) showed that copper, when PLX4720 present in the distillation process, reduces the dimethyl sulphide (DMS) content; this may be mainly responsible for the characteristic sensory defect of cachaça distilled in the absence of copper. However, it is well known that copper has the adverse effect of catalysing the formation of ethyl carbamate. GC–MS analyses of ethyl carbamate were performed by selected ion monitoring of m/z 62. The retention time
of EC was between 13.4 and 13.6 min. During sugar-cane juice fermentation, EC values changed from zero in the sugar-cane juice to a maximum level of 160 mg L−1 in wine (after 24 h of fermentation) as shown in Fig. 2. Average EC value after fermentation period from three repetitions was 122 mg L−1. Sugar-cane (Saccharum officinarum L.), the raw material for Brazilian cachaça, is classified as a cyanogenic crop, but its cyanide source is as yet unknown ( Beattie & Polyblank, 1995). As sugar-cane is poor in protein
content and copper was present at low concentrations in sugar-cane juice ( Table 1), these factors probably do not explain the quantity of EC formed. As shown in Fig. 2, there is EC formation during sugar-cane fermentation. Since no ingredient was added to the fermentation tank, these results suggest that EC production results from yeast metabolism. Carbamyl phosphate (CP) produced by yeast (Saccharomyces cerevisiae) can react with ethanol selleck screening library to generate ethyl carbamate in wine. CP comes from arginine, catalysed by carbamyl synthase, involving ATP, CO2, and ammonia ( Ingledew, Magnus, & Patterson, 1987). Intermediates such as carbamyl phosphate (CH4NO5P) are also easily formed in vitro. The results for EC content in the each
fraction of distilled samples are shown in Table 2. for each repetition (R – June, August, October). During distillation, the “head” is boiled off first. Components with low boiling point, e.g., ethyl acetate and methanol, are part of the “head”. At Progesterone the end of the first fraction collected (8 L), there was a high level of EC (average 59.7 mg L−1), confirming that this fraction was unsuitable for consumption and must be discarded. Their use in subsequent distillations, as is the current practice of traditional cachaça producers must not be tolerated. These results showed the importance of separating the head fraction from the heart fraction. In direct-fire alembic the wine boiling temperature reaches 100 °C and alcoholic vapour exits over 90 °C, lower than EC boiling temperature, which is 186 °C ( Neves et al., 2007). Despite these temperature conditions, EC is arrested during all distillation process. EC may be present in the head due to molecular interactions between ethanol and other chemical compounds present in the wine. During the middle distillation run (the ‘hearts’), the principal alcohol in all spirits, ethyl alcohol (ethanol), is distilled.
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