Determination of flavour compounds in beer using stir-bar sorptive extraction and solid-phase microextraction

Abstract

The analysis of volatile compounds in beer is important for quality control in the brewing industry. In this study, stir-bar sorptive extraction (SBSE) and solid-phase microextraction (SPME), two solvent-less enrichment techniques, were applied in combination with gas chromatography flame ionization detection (GC/FID) for the determination of four flavour compounds (isoamyl acetate, ethyl hexanoate, benzaldehyde, myrcene) in beer. Limits of detection, linearity and repeatability of both methods were determined using standard ethanol solutions, while accuracy was determined by conducting recovery tests on commercial beer samples. Both methods were characterized by high linearity (r > 0.996) and repeatability (RSD = 1.76-10.66%). When both methods were compared, higher recoveries were obtained by SBSE, with limits of detection 1.8-2.8 times lower compared with SPME. In the analysis of commercial beer samples using both methods, SBSE analysis resulted in higher recoveries, therefore demonstrating promise for the analysis of beer volatiles.

Development of Head Space Sorptive Extraction Method for the Determination of Volatile Compounds in Beer and Comparison with Stir Bar Sorptive Extraction

“…Most of these compounds have demonstrated to be odour-active compounds for the aroma of beers [28]. Similar results had been found in previous studies where different extraction techniques had been used [8,13,25,27,29]. However, other compounds such as benzaldehyde, guaiacol, linalool, hexanoic acid 2-phenylethyl ester or heptanol were only identified in some of the beer types.…”

“…In recent years, different applications of SBSE coupled with GC-MS for the aroma characterization of beers have appeared in the literature [8][9][10][11][12][13], but nevertheless, HSSE has been significantly less employed for this purpose. However, this latter technique has been successfully used for the determination of off-flavours in aged beers [14] and for the study of volatile compounds derived from hops, with similar results to those obtained when using SBSE [15].…”

Beer metabolomics: molecular details of the brewing process and the differential effects of late and dry hopping on yeast purine metabolism

“…Myrcene is one of most abundant molecules found in hop oil and was the only hop aroma compound that was able to be identified in this work. Myrcene was recently reported to be present at 3 μM in beer , which is at the detection limit of our technique. Therefore it is not surprising that it was not possible to identify more hop aroma compounds.…”

Comparison of sensory and chemical evaluation of lager beer aroma by gas chromatography and gas chromatography/mass spectrometry

“…Four different SPME fibres were tested prior to analysis: 100 µm PDMS, 85 µm polyacrylate, 50/30 µm DVB/CAR/PDMS and 65 µm PDMS/DVB. According to the literature, these fibres provide the best results for determining the volatile compounds in beer . All fibres (Supelco, Bellefonte, PA, USA) were conditioned in accordance with the manufacturer's instructions.…”