Identification of volatile organic compounds extracted by headspace solid-phase microextraction in specialty beers produced in Brazil

Beer is a very complex mixture, being an alcoholic beverage obtained by fermentation processes. The consumption and production of specialty beers in Brazil have increased in the past years; however, most Brazilian brewers still depend on imported commercial starter yeast strains and raw materials. Our data also indicate that volatile profile of Brazilian beers is more influenced by raw materials. The analysis of volatile compounds in beer is important for its quality control, and the presence of aromatic substances is related to the beverage acceptance and quality. In this study, headspace solid phase microextraction in combination with gas chromatography coupled to mass spectrometric detection was used for the identification of the volatile organic compounds in 30 samples of Brazilian Pilsen and ale beers. Ninety-nine volatile compounds were identified and grouped into ketones, terpenes, esters, higher alcohols, aldehydes, fatty acids, hydrocarbon and other minority compounds. Analysis of the principal components showed that the majority of specialty beers have similar chemical characteristics, their volatile profile being characterized mainly by esters and higher alcohols. Additional studies are necessary to better characterize Brazilian specialty beers; however, our results open perspectives for future research of possible indicators and markers that may serve for the purposes of certification, as well as quality control of the beverage. (C) 2017 The Institute of Brewing & Distilling