Construction of a comprehensive beer proteome map using sequential filter‐aided sample preparation coupled with liquid chromatography tandem mass spectrometry

The quality traits of beer, which include flavor, texture, foam stability, gushing, and haze formation, rely on contributions from beer proteins and peptides. Large‐scale proteomic analysis of beer is gaining importance, not only with respect to authenticity of raw material in beer but also to improve quality control during beer production. In this work, foam proteins were first isolated from beer by virtue of their high hydrophobicity. Then sequential filter‐aided sample preparation coupled with liquid chromatography and tandem mass spectrometry was used to analyze both beer protein and foam protein. Finally, 4692 proteins were identified as beer proteins, and 3906 proteins were identified as foam proteins. In total, 7113 proteins were identified in the beer sample. Several proteins contributing to beer quality traits, including lipid transfer protein, serpin, hordein, gliadin, and glutenin, were detected in our proteins list. This work constructed a comprehensive beer proteome map that may help to evaluate potential health risks related to beer consumption in celiac patients.     

Study of Chromatographic Fingerprint of the Flavor in Beer by HS-SPME-GC

The chromatographic fingerprint of the flavor in beer, which was obtained by analyzing 28 beer samples (6 tastes) from 4 breweries, was established by Headspace Solid-phase Microextraction coupled with Gas Chromatogram Flame Ionization Detector (HS-SPME-GC-FID). After Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) were used to process the GC data, not only could 28 beer samples be classified into three main types (draft beer, traditional beer, and dark beer), but also the same main type of beer samples could be further classified individually according to the breweries and tastes. In addition, 18 volatile compounds were identified by Gas Chromatogram Mass Spectrum (GC-MS). The results showed that HS-SPME-GC-FID was convenient, rapid, and precise in classifying beer samples according to different main types, breweries, and even tastes. Therefore, the method established in this paper was potential to be used for the identification of beer types and even the quality control of beer.     

GC-MS法检测生物检材中的白酒和啤酒

用GC-MS法分析白酒和啤酒中的成分,统计出白酒、啤酒的各自特征成分并加以比较。对添加不同量白酒、啤酒及白酒与啤酒混合物的胃内容物进行检验,对饮用不同量白酒、啤酒及白酒与啤酒混合物的人员分别采集血样进行检验,统计并总结出胃内容物及血液中白酒、啤酒的区分检验方法。当生物检材中乙醇含量大于0．3mg／mL时,利用该方法可以区分检材中的白酒和啤酒。     

稻壳吸附剂提高啤酒稳定性的研究

利用稻壳良好的吸附特性,制备成吸附剂用于提高啤酒的稳定性。稻壳粉碎与稀硫酸混合,240℃密封干馏,再以高温灼烧活化,得到对单宁有较强吸附能力的稻壳吸附剂。以此吸附剂去除啤酒中的部分单宁,以提高酒体的胶体稳定性,试验表明,每100ml啤酒以0．4g吸附剂在15℃下搅拌吸30min,可使酒中单宁量下降16．7％,从而减缓了引起啤酒混浊的缔合反应,使酒体稳定性明显提高。与聚乙烯聚吡咯烷酮比较,具有吸附速度快、吸附单宁更强及成本低廉的优点。     

A survey of ochratoxin A and aflatoxins in domestic and imported beers in Japan by immunoaffinity and liquid chromatography.

Analyses of ochratoxin A (OTA) and aflatoxins (AFs) in 94 imported beer samples from 31 producing countries and in 22 Japanese beer samples were performed by immunoaffinity column and reversed-phase liquid chromatography (LC) with fluorescence detection. Recoveries of OTA from beer samples spiked at 25 and 250 pg/mL were 86.1 and 88.2%, respectively. Recoveries of AFs were 98.4 and 98.9%, 95.4 and 95.5%, 101.2 and 97.8%, and 98.9 and 96.0%, respectively, from beer samples spiked at 4.1 and 41 pg AF B1, 4.45 and 44.5 pg AF B2, 4.7 and 47 pg AF G1, and 4.65 and 46.5 pg AF G2/mL. Detection limits were 1.0 pg/mL for OTA, 0.5 pg/mL for AFs B1 and B2, and 1.0 pg/mL for AFs G1 and G2. OTA was detected in 86 (91.5%) of 94 imported beer samples at a mean level of 10.1 pg/mL and in 21 (95.5%) of 22 Japanese beer samples at a mean level of 12.5 pg/mL. AF B1 was detected in 11 of 94 imported beer samples at a level of 0.5-83.1 pg/mL and in 2 of 22 Japanese beer samples at 0.5 and 0.8 pg/mL. Except for one beer sample from Peru, the samples contaminated with AFs were also contaminated with OTA. Although OTA was detected in most samples from various countries, AFs were detected in the beer samples from only a limited number of countries where AF contamination might be expected to occur because of their warm climate.     

Magnetic mixed hemimicelles solid-phase extraction of xanthohumol in beer coupled with high-performance liquid chromatography determination

In this study, silica-coated magnetic nanoparticles (Fe(3)O(4)/SiO(2) NPs) modified by cetyltrimethylammonium bromide (CTAB) were synthesized. They were successfully applied for extraction of xanthohumol in beer based on magnetic mixed hemimicelles solid-phase extraction (MMHSPE) coupled with high-performance liquid chromatography-ultraviolet determination. The main factors influencing the extraction efficiency including the surfactant amount, the beer pH, the extraction time, the desorption condition and the maximum extraction beer volume were optimized. Under the optimized conditions, a concentration factor of 60 was achieved by extracting 120 mL beer sample using MMHSPE and the detection limit of xanthohumol is 0.0006 mg/L. The proposed method was successfully applied for determination of xanthohumol in various beer samples with the xanthohumol contents in the range of 0.031-0.567 mg/L. The satisfactory recoveries (90-103%) were obtained in analyzing spiked beer samples.     

The Role of Bioactive Phenolic Compounds on the Impact of Beer on Health

This review reports recent knowledge on the role of ingredients (barley, hop and yeasts), including genetic factors, on the final yield of phenolic compounds in beer, and how these molecules generally affect resulting beer attributes, focusing mainly on new attempts at the enrichment of beer phenols, with fruits or cereals other than barley. An entire section is dedicated to health-related effects, analyzing the degree up to which studies, investigating phenols-related health effects of beer, have appropriately considered the contribution of alcohol (pure or spirits) intake. For such purpose, we searched Scopus.com for any kind of experimental model (in vitro, animal, human observational or intervention) using beer and considering phenols. Overall, data reported so far support the existence of the somehow additive or synergistic effects of phenols and ethanol present in beer. However, findings are inconclusive and thus deserve further animal and human studies.     

Simultaneous determination of E-2-nonenal and beta-damascenone in beer by reversed-phase liquid chromatography with UV detection

A method for the simultaneous determination of E-2-nonenal and beta-damascenone in beer by reversed-phase liquid chromatography using UV detection is presented. The method consists of beer steam distillation, followed by an extraction/concentration step using Sep-Pak Plus C18 RP cartridges and determination by HPLC at 226 nm UV-absorption maximum. The identity of the compounds was confirmed by GC analysis with MS detection of the isolated fractions. A recovery factor of approximately 80% was obtained for beta-damascenone with a R.S.D. of 3%. E-2-Nonenal and beta-damascenone were monitored in a comparative study of fresh and either naturally and forced aged beer. The results obtained show that both compounds have a similar behaviour through an extended storage of beer and consequently can be used as good analytical markers of beer ageing. Nevertheless, the use of beta-damascenone seems to be more convenient because this compound appears in beer in higher concentrations than E-2-nonenal, thus making it easier to measure.     

啤酒主要成分的近红外光谱法测定

根据近红外光谱的振动吸收强度与有机分子官能团含量的线性关系,用偏最小二乘法,对啤酒的近红外光谱与其中的酒精度、原麦汁浓度以及总酸含量等3种主要成分进行了线性回归,并建立起相关的模型。用该模型对未知啤酒样品中的上述3种成分的含量进行预测,取得了令人非常满意的结果。可望作为啤酒厂的一种快捷而准确的检测方法予以推广。     

Electrospray ionization mass spectrometry fingerprinting of beer

After just simple degassing, dilution, pH adjustment and direct flow injection, characteristic fingerprint spectra of beer samples have been obtained by fast (few seconds) electrospray ionization mass spectrometry (ESI-MS) analysis in both the negative and positive ion modes. A total of 29 samples belonging to the two main beer types (lagers and ales) and several beer subtypes from USA, Europe and Brazil could be clearly divided into three groups both by simple visual inspection of their ESI(+)-MS and ESI(-)-MS fingerprints as well as by chemometric treatment of the MS data. Diagnostic ions with contrasting relative abundances in both the positive and negative ion modes allow classification of beers into three major types: P = pale (light) colored (pilsener, pale ale), D = dark colored (bock, stout, porter, mild ale) and M = malt beer. For M beers, samples of a dark and artificially sweetened caramel beer produced in Brazil and known as Malzbiers were used. ESI-MS/MS on these diagnostic beer cations and anions, most of which are characterized as arising from ionization of simple sugars, oligosaccharides, and iso-alpha-acids, yield characteristic tandem mass spectra adding a second and optional MS dimension for improved selectivity for beer characterization by fingerprinting. Direct ESI-MS or ESI-MS/MS analysis can therefore provide fast and reliable fingerprinting characterization of beers, distinguishing between types with different chemical compositions. Other unusual polar components, impurities or additives, as well as fermentation defects or degradation products, could eventually be detected, making the technique promising for beer quality control.     

Beer: An Ancient Yet Modern Biotechnology

The brewing of beer is a complex process that draws on a diversity of sciences and technology, of which chemistry is but one. This paper focuses on the chemistry of the brewing process and of the finished product. It examines each of the main classes of molecule found in beer, considers their contribution to quality and their origins in the brewing process. The study of beer and its production provides an excellent illustrative example for teaching how raw materials and the manner by which they are processed determine the acceptability of a product. Beer, whilst 90%+ water, contains a wide range of chemical species which establish its properties. Apart from ethanol (the common denominator amongst all alcoholic beverages), beer contains substances that determine its flavor, foam, and color. The flavorsome components of beer include the bitter iso-a-acids and aromatic essential oils from hops, along with esters, acids, sulfur-containing compounds and vicinal diketones from yeast. The foaminess of beer depends on the presence of carbon dioxide but also of surface-active materials like amphipathic polypeptides from malt and the bitter substances from hops. The color is due to Maillard reaction products generated largely during the kilning of malt. The malting and brewing processes (which are briefly described) are designed to maximize the extraction and digestion of barley starch and protein, yielding highly fermentable wort. The processes are also designed to eliminate materials that can have an adverse effect on beer quality, such as the haze-forming polyphenol from barley and hops and the lipids and oxygen that, together, can cause beer to stale.     

Preparation of novel solid-phase microextraction fibers by sol-gel technology for headspace solid-phase microextraction-gas chromatographic analysis of aroma compounds in beer

3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) was first used as precursor as well as selective stationary phase to prepare the sol-gel-derived TMSPMA-hydroxyl-terminated silicone oil (TMSPMA-OH-TSO) solid-phase mircroextraction (SPME) fibers for the analysis of aroma compounds in beer. TMSPMA-OH-TSO was a medium polarity coating, and was found to be very effective in carrying out simultaneous extraction of both polar alcohols and fatty acids and nonpolar esters in beer. The extraction temperature, extraction time, and ionic strength of the sample matrix were modified to allow for maximium sorption of the analytes onto the fiber. Desorption temperature and time were optimized to avoid the carryover effects. To check the matrix effects, several different matrices, including distilled water, 4% ethanol/water (v/v) solution, a concentrated synthetic beer, a "volatile-free" beer and a real beer were investigated. Matrix effects were compensated for by using 4-methyl-2-pentanol as internal standard and selecting the "volatile-free" beer as working standard. The method proposed in this study showed satisfactory linearity, precision and detection limits and accuracy. The established headspace SPME-gas chromatography (GC) method was then used for determination of volatile compounds in four beer varieties. The recoveries obtained ranged from 92.8 to 105.8%. The relative standard deviations (RSD, n = 5) for all analytes were below 10%. The major aroma contributing substances of each variety were identified via aroma indexes.     

Heterocyclic nitrogen compounds in whisky and beer

Summary Differences in the composition of the heterocyclic nitrogen compounds in whisky and beer were studied using capillary gas chromatography. The raw materials common to both whisky and beer lead to similar N-heterocycles being detected in both beverages. Pyridines, pyrazines, and thiazoles could be identified in both beverages. In addition, pyrroles were detected in beer and quinolines in whisky. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Evaluation of beer deterioration by gas chromatography-mass spectrometry/multivariate analysis: a rapid tool for assessing beer composition

Beer stability is a major concern for the brewing industry, as beer characteristics may be subject to significant changes during storage. This paper describes a novel non-targeted methodology for monitoring the chemical changes occurring in a lager beer exposed to accelerated aging (induced by thermal treatment: 18 days at 45 °C), using gas chromatography-mass spectrometry in tandem with multivariate analysis (GC-MS/MVA). Optimization of the chromatographic run was performed, achieving a threefold reduction of the chromatographic time. Although losing optimum resolution, rapid GC runs showed similar chromatographic profiles and semi-quantitative ability to characterize volatile compounds. To evaluate the variations on the global volatile signature (chromatographic profile and m/z pattern of fragmentation in each scan) of beer during thermal deterioration, a non-supervised multivariate analysis method, Principal Component Analysis (PCA), was applied to the GC-MS data. This methodology allowed not only the rapid identification of the degree of deterioration affecting beer, but also the identification of specific compounds of relevance to the thermal deterioration process of beer, both well established markers such as 5-hydroxymethylfufural (5-HMF), furfural and diethyl succinate, as well as other compounds, to our knowledge, newly correlated to beer aging.     

气相色谱-质谱法分析啤酒中酒花香气成分

利用顶空固相微萃取-气相色谱质谱技术(HS-SPME/GC-MS)建立了定量分析啤酒中19种源自酒花的微量香气成分的方法。研究了不同萃取头、萃取时间、萃取温度对萃取效果的影响,最终确定HS-SPME最佳萃取条件为采用PDMS萃取头对啤酒样品在50℃下萃取60 min。在最佳萃取条件下,采用啤酒为基体以减少基体干扰,建立标准曲线,随后在SIM模式下以萜品烯-4-醇为内标定量测定了啤酒中酒花香气物质的含量。19种物质的回收率在81.2%～116.8%之间,相对标准偏差(RSD)低于9.8%,在5个加标浓度下,R2大于0.99。相比于传统方法,本方法所需样品量少、灵敏度高、操作过程简便,能准确的检测出啤酒中酒花香气物质的含量。     

Towards the Use of Adsorption Methods for the Removal of Purines from Beer

Beer corresponds to a fermented alcoholic beverage composed of several components, including purine compounds. These molecules, when ingested by humans, can be catabolized into uric acid, contributing to uric acid’s level increase in serum, which may lead to hyperuricemia and gout. To assure a proper management of this disease, physicians recommend restrictive dietary measures, particularly by avoiding the consumption of beer. Therefore, it is of relevance to develop efficient methods to remove purine compounds from alcoholic beverages such as beer. In this review, we provide an introduction on fermented alcoholic beverages, with emphasis on beer, as well as its purine compounds and their role in uric acid metabolism in the human body in relation to hyperuricemia and gout development. The several reported enzymatic, biological and adsorption methods envisaging purine compounds’ removal are then reviewed. Some enzymatic and biological methods present drawbacks, which can be overcome by adsorption methods. Within adsorption methods, adsorbent materials, such as activated carbon or charcoal, have been reported and applied to beer or wort samples, showing an excellent capacity for adsorbing and removing purine compounds. Although the main topic of this review is on the removal of purine compounds from beer, other studies involving other matrices rather than beer or wort that are rich in purines are included, since they provide relevant clues on designing efficient removal processes. By ensuring the selective removal of purine compounds from this beverage, beer can be taken by hyperuricemic and gouty patients, avoiding restrictive dietary measures, while decreasing the related healthcare economic burden.     

Determination of Volatile Markers from Magnum Hops in Beer by In-Tube Extraction—Gas Chromatography—Mass Spectrometry

ABSTRACT

A chromatographic method was developed for the identification of volatile markers from Magnum hops in two types of beer. The study was initially performed with Magnum hop pellets and hop essential oil and subsequently with traditional and flavored beer during the primary fermentation. The volatile compounds were isolated employing the in-tube extraction (ITEX) technique followed by identification and quantification through gas-chromatography—mass spectrometry (GC-MS) operating in scan mode. The main authentication markers identified in traditional beer were from aromatic compounds, aldehydes and alcohol esters. The most predominant authentication marker compounds in beer flavored with Magnum hop essential oil were obtained from terpenoids, followed by acid esters, alcohol esters and alcohol classes. A unique feature of this study was represented by the discriminant markers for the authentication of Magnum hop variety, identified in hop pellets, hop essential oil and flavored beer. The application of this methodology can be used for optimization of brewing technology and process parameters in view of prolonging fruity hop flavor stability of Romanian beers.     

Separation and quantification of beer carbohydrates by high-performance liquid chromatography with evaporative light scattering detection

An HPLC method with an evaporative light scattering detector was optimized and validated for quantification of carbohydrates in beer. The chromatographic separation was achieved using a Spherisorb NH2, 5 microm chromatographic column and gradient elution with acetonitrile/water. The determinations were performed in the linear range of 0.05-5.0 g/L for fructose, 0.05-5.0 g/L for glucose, 0.05-15.0 g/L for maltose, 0.05-10.0 g/L for maltotriose, and 0.05-5.0 g/L for maltotetraose. The detection limits were 0.005 g/L for fructose, 0.008 g/L for glucose, and 0.01 g/L for maltose, maltotriose, and maltotetraose. The reliability of the method in terms of precision and accuracy was evaluated in three beer matrices, low alcohol beer, 6% alcohol beer, and beer made with part of adjuncts (4.5% alcohol). Relative standard deviations (RSDs) ranged between 1.59 and 5.95% (n = 10), and recoveries ranged between 94 and 98.4%.     

Development of an HPLC-Method for the Determination of E-2-Nonenal in Beer using Column Switching Techniques

Abstract

E-2-nonenal is an important compound formed during ageing of beer. It has a flavour threshold value of about 0.1 μg/l. A method is described for isolation of E-2-nonenal from beer by solid phase extraction. After extraction E-2-nonenal is derivatized with dansylhydrazine and analyzed with reversed phase HPLC using column switching techniques. The combination of on-line preconcentration of the derivative and heartcutting enables the analysis of E-2-nonenal in beer at natural levels.