Selected Saccharomyces cerevisiae yeast strains and accurate separation of distillate fractions reduce the ethyl carbamate levels in alembic cachaças

Abstract

Ethyl carbamate (EC) is a potentially toxic compound that may be present at concentrations above maximum limits established in alcoholic beverages, such as cachaça. Most traditional alembic cachaça is produced on a small scale using empirical knowledge. The fermentation step is conducted using yeasts that are endogenous to the sugar cane, and the distillation process is relatively uncontrolled. In this study, gas chromatography coupled with mass spectrometry was used to determine the EC levels in distillate musts and fractions produced by spontaneous or selected Saccharomyces cerevisiae strains. The aim was to verify the influence of selected strains as starters for fermentation compared with spontaneous fermentation on EC formation. The distillate fractions from these two production processes were also analysed. Our results demonstrated higher levels of EC (which surpass the limits defined by Brazilian law) in cachaças produced by spontaneous fermentation (50%) compared with the selected strains (30%); and the distillation step showed great contribution for the reduction of the compound. From must to distillate fractions we found an average decrease on EC levels of 62% using selected strains and 44% for the spontaneous fermentation. In addition, careful separation of the distillation fractions was crucial for producing high-quality and safe beverages.