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

José E Ruvalcaba,Remedios Castro,Carmelo G Barroso,Enrique Durán-Guerrero

doi:10.3390/foods9030255

José E Ruvalcaba, Remedios Castro + Show 2 more

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https://doi.org/10.3390/foods9030255

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Abstract

A headspace sorptive extraction method coupled with gas chromatography–mass spectrometry (HSSE–GC–MS) was developed for the determination of 37 volatile compounds in beer. After optimization of the extraction conditions, the best conditions for the analysis were stirring at 1000 rpm for 180 min, using an 8-mL sample with 25% NaCl. The analytical method provided excellent linearity values (R2 > 0.99) for the calibration of all the compounds studied, with the detection and quantification limits obtained being low enough for the determination of the compounds in the beers studied. When studying the repeatability of the method, it proved to be quite accurate, since RSD% values lower than 20% were obtained for all the compounds. On the other hand, the recovery study was successfully concluded, resulting in acceptable values for most of the compounds (80–120%). The optimised method was successfully applied to real beer samples of different types (ale, lager, stout and wheat). Finally, an analytical comparison of the optimised HSSE method, with a previously developed and validated stir bar sorptive extraction (SBSE) method was performed, obtaining similar concentration values by both methods for most compounds.

Highlights

Beer is one of the oldest and most widely consumed alcoholic beverages in the world, and the third most popular drink after water and tea [1]
Other authors have indicated that, an increase increase in temperature temperature shortens shortens the time required required to reach equilibrium, it increases the solubility of the analytes in water, which means that the amount extracted by the stirring stirring bar bar may may decrease decrease [17]
It is clear that headspace sorptive extraction (HSSE) is an appropriate method to determine the different types of volatile compounds in beers

Summary

Introduction

Beer is one of the oldest and most widely consumed alcoholic beverages in the world, and the third most popular drink after water and tea [1]. The fermentation of sugars from starch produces ethanol and carbon dioxide [2]. Most modern beers are brewed in the presence of hops, which add bitterness and aroma to the finished beer, as well as acting as a natural preservative and stabilising agent. The final aroma and taste of a particular beer is the result of hundreds of aromatically active compounds, which are produced during the course of the brewing process. The vast majority of the compounds are produced during the fermentation phase and are mainly metabolic intermediates or yeast by-products. Esters and vicinal diketones, which determine the final quality of each beer, are some of the key compounds produced by the yeast [3]. While higher alcohols and esters are positive compounds that produce a pleasant aroma, vicinal diketones are often considered

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