Volatile Compounds In Beer Research Articles

Discrimination and quantification of volatile compounds in beer by FTIR combined with machine learning approaches

The composition of volatile compounds in beer is crucial to the quality of beer. Herein, we identified 23 volatile compounds, namely, 12 esters, 4 alcohols, 5 acids, and 2 phenols, in nine different beer types using GC–MS. By performing PCA of the data of the flavor compounds, the different beer types were well discriminated. Ethyl caproate, ethyl caprylate, and phenylethyl alcohol were identified as the crucial volatile compounds to discriminate different beers. PLS regression analysis was performed to model and predict the contents of six crucial volatile compounds in the beer samples based on the characteristic wavelength of the FTIR spectrum. The R2 value of each sample in the prediction model was 0.9398–0.9994, and RMSEP was 0.0122–0.7011. The method proposed in this paper has been applied to determine flavor compounds in beer samples with good consistency compared with GC–MS.

Preliminary Study of the Effect of Short Maceration with Cherry and Oak Wood Chips on the Volatile Composition of Different Craft Beers

In the last few years, the production and consumption of craft beers has increased notably. However, there is restricted knowledge about the potential impact of chips from different wood species on beer quality. Thus, this work aimed to evaluate the effect of the addition of wood chips from cherry and oak species—after the fermentation was completed and during a brief maceration time—on the volatile composition of three different beer groups (Ale, Lager, and Porter) through a headspace solid-phase dynamic extraction (HS-SPDE) and GC-MS analysis. Fifty-six volatile compounds from different chemical families (esters, alcohols, terpenes, acids, aldehydes, ketones, and pyrazines) were detected, identified, and considered in this study. In general, the volatile composition of the beers macerated with wood chips was very similar to that of the control beers. However, the control beers showed higher volatile compound levels. The results suggest potential interactions between beer volatile compounds and the wood chips during maceration. The outcomes of this research could be of practical interest to brewers since they could improve the knowledge of the impact of short-time contact and low wood chip concentration on the volatile composition of different craft beers.

Isolation, Selection and Characterization of Wild Yeasts with Potential for Brewing

Ninety-two wild yeasts were isolated from different fruits, for possible use in brewing, using the technological traits of carbohydrate fermentation and hydrogen sulfide production. Twelve yeasts were selected for identification by sequencing (D1/D2 domain or ITS1-5.8S-ITS2 region) and their volatile compounds production analyzed using gas chromatography. From these analyses, three yeasts were chosen for further characterization and beer production. Strains were characterized by their tolerance to osmotic and ethanol stress, their flocculation profile, growth at different temperatures, apparent attenuation (percentage of sugars converted into alcohol), estimated ABV (alcohol by volume) and reducing sugar profile. Beers were analyzed for alcohol content and sensorial analysis. The isolates CL011 and PB111 (Saccharomyces cerevisiae) and CB341 (Wickerhamomyces anomalus) showed promising properties for brewing, which included high production of interesting volatile compounds (esters, terpenes, lactones, and C13-norisoprenoids) by CL011, a neutral profile by PB111, and the production of non-classic beer volatile compounds by CB341 in a mixed culture. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2022.2031777 .

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

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.

The influence of packaging material on volatile compounds of pale lager beer

Abstract This research aimed to evaluate the influence of different packaging materials (glass bottle, PET bottle, aluminium can and keg) on eleven (acetaldehyde, dimethyl sulphite, ethyl acetate, isoamyl acetate, propanol, isobutanol, isoamyl alcohol, diacetyl, higher alcohols, esters and pentanedione) industrial pale lager beer volatile compounds concentration changes and their stability during a six-month storage time. The analyses were performed on a single type of pale lager beer under different packaging regimes. The results showed that diacetyl and pentanedione were significantly higher in PET bottles than in other packaging (especially glass bottle). Dimethyl sulphide concentration was, at the end of a six month storage, significantly lower (5 μg/L) in PET bottles than in glass bottle (48 μg/L). Can and keg also showed good preservation properties for volatiles. This is important for the brewing industries because the reported changes influence the consumers’ perception and greatly affect the acceptance of beer.

Variation in Sensory Attributes and Volatile Compounds in Beers Brewed from Genetically Distinct Malts: An Integrated Sensory and Non-Targeted Metabolomics Approach

Previous research demonstrates that barley genetics can influence beer flavor. However, the chemical basis for differences in beer flavor attributed to barley is not well defined. Here, the associations between beer volatile compounds and sensory descriptors were investigated in a controlled experiment, whereby barley genotype was the main driver of variation in the system. Beer was brewed from three advanced barley breeding lines and compared to a CDC Copeland control. Sensory studies were performed via three independent panels (a consumer, brewery, and laboratory panel). The results suggest that the four beer samples have distinct flavor profiles that could be discriminated by the three sensory panels. Volatile compounds for the four beers were characterized using HS/SPME-GC-MS; quantitation and annotation were performed using a non-targeted metabolomics approach on 397 detected compounds. The O2PLS data analysis supports that alkane/alkenes, benzenoids, amides/amines, and fatty acid esters were associated with the most desirable lager traits, compared to Maillard Reaction Products that were more abundant in the beers with “non-ideal” lager traits. Taken together, these data further support the role of barley genetics in beer flavor and provide new information on the types of volatile metabolites that can vary in controlled systems.

Development of a stir bar sorptive extraction method to study different beer styles volatile profiles.

A stir bar sorptive extraction method coupled to Gas Chromatography-Mass Spectrometry for the analysis of 52 volatile compounds in beer has been developed. The final optimized conditions were: 50 mL sample volume, 180 min extraction time, 25% (w/v) NaCl content and polydimethylsyloxane stir bars. Good values of linearity (R2 > 0.99) were achieved for the calibration lines of all the compounds. The limits of detection and quantification obtained were low enough for the determination of the volatile compounds in the samples and the recovery values obtained for the majority of the compounds were between 80% and 120%. The precision of the method was also studied and acceptable values for this type of extraction technique were obtained (<20%). 30 samples of different styles of beers (ale, lager, stout and wheat) were analysed and their aromatic profile was characterised. Multivariate statistical techniques allowed the correct classification of the samples according to their volatile composition.

Impact of triticale malt application on physiochemical composition and profile of volatile compounds in beer

In brewing industry, adjuncts may replace malt, but they may also represent a raw material for brewing beer demonstrating different, specific organoleptic qualities. Triticale grain may give good quality malts, characterised by high extraction capacity, high diastatic power and short saccharification time. The purpose of the research was to determine the impact of triticale malt application on physiochemical composition and profile of volatile compounds in beer. In fermented wort, the content of ethyl alcohol, extract, sugars, general acidity, colour, haze, free aminonitrogen and volatile compound profile (GC-SPME) was determined. Beers produced from the triticale malt or with use of a malt mixture were characterised by higher acidity and lower ethyl acetate butanol and isoamyl alcohol. The worts analysed in the process demonstrated parameters normative for pale malts. The triticale malt may be an alternative for barley malt.

Application of response surface design to optimise the chromatographic analysis of volatile compounds in beer

Application of response surface design to optimise the chromatographic analysis of volatile compounds in beer

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. Copyright © 2017 The Institute of Brewing & Distilling

Flavour-active volatile compounds in beer: production, regulation and control

Many classes of compounds have been shown to play an important role in the development of flavour characteristics of beer. This significantly influences its taste and sensory properties, thus affecting its market performance. Despite the intensive research aimed at unravelling the precise mechanism and regulation of flavour formation in beer, current knowledge remains far from complete. Several reviews are available on the general composition of beer and yeast metabolic pathways involved in the production of volatile compounds in beer. However, a limited amount of work has been reported concerning the influence of some of the beer constituents and other important parameters on beer flavour. This paper reviews the current knowledge of the biochemistry behind flavour formation in beer and discusses the different factors that influence its formation and how it can be controlled during brewery fermentation. Copyright © 2017 The Institute of Brewing & Distilling

Development of stable isotope dilution assays for the quantitation of free phenolic acids in wheat and barley and malts produced thereof

Free phenolic acids present in cereal malts serve as precursors of different volatile compounds in beer. To study their generation from wheat and barley on the way to the respective malts, stable isotope dilution assays (SIDAs) were developed using high-performance liquid chromatography–tandem mass spectrometry to quantitate the free phenolic acids caffeic, cinnamic, p-coumaric, ferulic, sinapic, and vanillic acid in the grain as well as in the malts produced thereof. An optimised extraction procedure using methanol instead of water in combination with the newly developed SIDAs enabled their selective and sensitive quantitation with low limits of detection and limits of quantitation as well as good recoveries. In kiln-dried wheat malt, the most abundant free phenolic acid was sinapic acid with 2.30 mg/kg dry mass, while in kiln-dried barley malt ferulic acid predominated with 2.76 mg/kg dry mass. The concentration of the latter in kiln-dried malt is of special interest, because this acid is a well-known precursor of the important wheat beer aroma compound 2-methoxy-4-vinylphenol. The concentration of cinnamic acid, the precursor of the toxicologically relevant vinylbenzene (styrene), in kiln-dried wheat and barley malt were 0.56 and 0.97 mg/kg dry mass, respectively. Generally, kiln-dried barley malt showed higher concentrations of most phenolic acids in comparison to kiln-dried wheat malt.

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

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. Copyright © 2015 The Institute of Brewing & Distilling

Effects of fermentation temperature on the composition of beer volatile compounds, organoleptic quality and spent yeast density

Production of good quality beer is dependent largely on the fermentation temperature and yeast strains employed during the brewing process, among others. In this study, effects of fermentation temperatures and yeast strain type on beer quality and spent yeast density produced after wort fermentation by two commercial yeast strains were investigated. Beer samples were assessed for colour, clarity and foam head stability using standard methods, whilst the compositions and concentration of Beer Volatile Compounds (BVCs) produced were assessed using GC-MS. The spent yeast density, measured as dry cell weight, ranged between 1.84 - 3.157 mg/ml for both yeast strains with the highest yield obtained at room temperature fermentation. A peak viable population of 2.56 x 10 7 cfu/ml was obtained for strain A, also during fermentation at room temperature. The foam head of the beers produced at 22.5oC was most stable, with foam head ratings of 2.66 and 2.50 for yeast strain A and B, respectively. However, there was no significant ( p = 0.242) difference in colour intensity between the beers produced at the different fermentation temperatures. Eight different BVCs were detected in all beer samples and were found to affect the organoleptic properties of the beer produced. Further optimizations are required to determine the effects of other parameters on beer quality.

Influence of Pasteurising Intensity on Beer Flavour Stability

While it is preferred that flavour improves during the beer maturation process, formation of undesirable flavours inevitably occurs during beer storage. Beer ageing problems occur during beer storage and can damage the beer style, especially for lager beer of a more delicate style. In this research, the impact of pasteurising intensity on beer ageing and flavour stability was studied. Through process adjustments, three types of bottled beer were obtained from one fermenter and classified by their PU values as 2 PU, 8 PU and 14 PU. The dynamic changes of related indices (taken every month) characterizing the ageing and flavour of the beer under different pasteurising intensities were investigated during a 6-month room temperature storage period. The key factors of colour, the thiobarbituric acid (TBA) index, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, bitterness and total polyphenol composition, the concentration of beer volatile compounds (BVCs), and 5-hydroxymethyl furfural (5-HMF) were examined. Statistically, the 14 PU sample showed the highest degree of damage, with the greatest flavour change compared to the other samples.

Beer Volatile Compounds and Their Application to Low-Malt Beer Fermentation

Low-malt beers, in which the amount of wort is adjusted to less than two-thirds of that in regular beer, are popular in the Japanese market because the flavor of low-malt beer is similar to that of regular beer but the price lesser than that of regular beer. There are few published articles about low-malt beer. However, in the production process, there are many similarities between low-malt and regular beer, e.g., the yeast used in low-malt beer fermentation is the same as that used for regular beer. Furthermore, many investigations into regular beer are applicable to low-malt beer production. In this review, we focus on production of volatile compounds, and various studies that are applicable to regular and low-malt beer. In particular, information about metabolism of volatile compounds in yeast cells during fermentation, volatile compound measurement and estimation methods, and control of volatile compound production are discussed in this review, which concentrates on studies published in the last 5-6 years.

Method optimization by solid-phase microextraction in combination with gas chromatography with mass spectrometry for analysis of beer volatile fraction

A simple and sensitive method for the analysis of beer volatile compounds was optimised using headspace solid-phase microextraction (SPME) and gas chromatography with mass detection. Headspace SPME using a 75 μm Carboxen-polydimethylsiloxane (CAR-PDMS) fiber provided effective sample enrichment and enabled extraction of a wide variety of compounds. The reproducibility depended on the compounds, with a mean value of 1.4% for alcohols, 3.3% for ethers, 6.7% for aldehydes, 3.4% for acids, 1.7% for aromatic compounds, 2.4% for esters, 7.4% for hydrocarbons, 1.8% for alicyclic compounds, and 3.4% for heterocyclic compounds. The optimised methodology can be used to compare volatile profile from different types of beers and eventually to study the evolution of a particular beer during aging.

Determination of DMS and other Volatile Compounds in Beer by Headspace Capillary Gas Chromatography and Flame Ionisation Detection

La determination de volatils de la biere par chromatographie en phase gazeuse dans l'espace de tete avec la methode de detection par ionisation de flamme du Comite des Analyses de l'Institute of Brewing a ete evaluee par les membres du Comite des Analyses de l'European Brewery Convention et par quelques membres de l'American Society of Brewing Chemists. Les composes analyses etaient l'acetaldehyde, le dimethylsulfure, l'acetate d'ethyle, le n-propanol, les alcools isoamyliques et les acetates d'isoamyle. Les etalons internes utilises etaient l'ethylmethyl-sulfure et le n-butanol. Apres trois essais collaboratifs preliminaires, un quatrieme dernier essai a ete effectue sur trois bieres dans 15 laboratories. La repetabilite (r 95 ) et la reproductibilite (R 95 ) ont ete obtenues par 12 laboratoires. Compte tenu que trop de membres n'ont pas suivi exactement la methode proposee et que les valeurs de reproductibilite ont ete jugees insuffisantes, il a ete decide de ne pas inclure la methode dans l'Analytica EBC ent tant que methode officielle mais plutot comme methode guide avec la notice mentionnee ci-dessus.

A Simple Method for the Determination of Hydrogen Sulfide Concentration in Beer

We have evaluated a hydrogen sulfide (H2S) analyzer equipped with a gas-permeable tube as a possible method for the rapid determination of H2S in beer (HSA method). The H2S analyzer responded strongly to H2S and very weakly to other volatile compounds in beer, indicating that the selective determination of H2S is possible. Repeatability studies showed that the coefficient of variation for the HSA method was 0–8%. Recovery studies showed that H2S recovery using the HSA method was ≈100%. These results indicated that the H2S concentration can be determined with a high degree of accuracy using the HSA method. Furthermore, the HSA method is very simple and only requires 5 min/sample for the analysis.