Assessment of Staling Aldehydes in Lager Beer under Maritime Transport and Storage Conditions.

Beer flavor stability is greatly influenced by external temperature, vibrations, and longer delivery times. The present study assessed the impact of transport and storage conditions on staling aldehyde evolution in lager beers across five sample groups (fresh, transport, and storage simulation, and their controls), which differed in their bottle opening system (either crown cap or ring pull cap). Maritime transport conditions (45 days of travel, vibrations of 1.7 Hz, and warm temperatures (21-30 °C)) were simulated, together with storage time in a distributor's warehouse (up to 75 days). The results revealed that the concentration of Strecker aldehydes increased more quickly after transport and storage simulation in beer bottles with the ring pull cap opening system, and the contents of 2-methylpropanal and 3-methylbutanal, in particular, were up to three times higher. Benzaldehyde content also increased significantly, by 33% on average, in these samples. Hexanal was only found in beers with a ring pull cap that underwent transport simulation. Further storage after transport simulation significantly reduced the content of 2-methylpropanal, 3-methylbutanal, and hexanal, by 73%, 57%, and 43%, respectively, suggesting the formation of a bound state. 5-hydroxymethylfurfural was continuously increased by 78.5% and 40.5% after the Transport and Transport & Storage simulations, respectively. Transport conditions lead to a slight increase, of 0.6 EBC units, in beer color.

Recent innovations in the production of selected specialty (non-traditional) beers.

Customer demand for product diversity is the key driving force for innovations in the brewing industry. Specialty beers are regarded as a distinct group of beers different from two major types, lagers and ales, without established definitions or boundaries. Specialty beers, including low- to no-alcohol beer, low carbohydrate beer, gluten-free beer, sour beer, probiotic beer, and enriched beer, are exclusively brewed and developed keeping in mind their functionality, the health and wellbeing of the consumer, and emerging market trends. Compared with conventional beer-brewing, the production of specialty beers is technologically challenging and usually requires additional process steps, unique microorganisms, and special equipment, which in turn may incur additional costs. In addition, the maintenance of quality and stability of the products as well as consumer acceptability of the products are major challenges to successful commercialization. A harmonious integration of traditional brewing practices and modern technological approaches may hold potential for future developments. In the present review, latest developments in the fermentative production of selected specialty beers are discussed.

Rapid Single Cell Detection of Lactic Acid Bacteria in the Beer Using Bioluminescence Method.

　In this study, we developed a system, known as MicroStarTM Rapid Microbe Detection System (RMDS) , to detect Lactobacillus brevis, which usually requires 2-4 days for examination by the conventional plate count procedure, for beer quality control using a bioluminescence method within 24 hr and also aimed to develop a technology to detect bacterial growth without the need for cultivation. We used a highly sensitive luminous reagent that increased the activity of the luciferin- luciferase reaction to 2.5×10－18 mol ATP/0.2 µl and could detect even a single lactic acid bacterial cell. The limitation of the method was that ATP derived from the beer hindered bacterial measurement and the supply of energy source to secure ATP of lactic acid bacterial cell. The sample beer was filtered through a membrane filter, avoiding the formation of beer foam to the best extent, the filter was cleaned with 10% ethanol and 0.1% sodium hydrogen carbonate solution, and incubated on a GMY agar plate (1% glucose, 0.2% malic acid, 0.67% yeast nitrogen base, 1% agar; pH 5.2) at room temperature for 2 hr. Post incubation of the filter, bacterial cell count was measured with RMDS. This method could overcome the hindrance of ATP measurement and could stably detect lactic acid bacteria without the need for cultivation.

Forced into aging: Analytical prediction of the flavor-stability of lager beer. A review.

Despite years of research, sensory deterioration during beer aging remains a challenge to brewing chemists. Therefore, sensorial and analytical tools to investigate aging flavors are required. This review aims to summarize the available analytical methods and to highlight the problems associated with addressing the flavor-stability of beer. Carbonyls are the major contributors to the aroma of aged pale lager beer, which is especially susceptible to deterioration. They are formed via known pathways during storage, but, as recent research indicates, are mainly released from the bound-state during aging. However, most published studies are based on model systems, and thus the formation and breakdown parameters of these adducts are poorly understood. This concept has not been previously considered in previous forced-aging analysis. Only weak parallels can be drawn between forced and natural aging. This is likely due to the different activation energies of the chemical processes responsible for aging, but may also be due to heat-promoted release of bound aldehydes. Thus, precursors and their binding parameters must be investigated to make appropriate technological adjustments to forced-aging experiments. In combination with sophisticated data analysis, the investigation of volatile indicators and non-volatile precursors can lead to more reliable predictions of flavor stability.

[The Student t-test is a beer test]. / De Student-t-toets is een biertoets.

The Student-t-test, one of the most used statistical tests in medicine, was developed by a beer brewer. From around 1900, the Irish Guinness brewery started recruiting scientists for the position of brewer in order to apply science to the production of beer in large quantities while maintaining consistency in terms of quality. One of these brewers was mathematician and chemist William Sealy Gosset (1876-1937). He developed statistical methods to deal with small sample surveys. Gosset's methods, and the accompanying t-distribution tables, enabled Guinness to take intelligent decisions about which ingredients to use, allowing them to produce high-quality beer that consistently tasted the same. Gosset wanted to publish his findings in scientific journals; however, the Guinness brewery was unwilling, as this could jeopardise their advantage over other breweries. They came to a compromise, in which Guinness allowed Gosset to publish his findings, as long as he used a pseudonym: Student. The Student's t-distribution remains one of the cornerstones of modern statistics.

Assessment of beer quality based on foamability and chemical composition using computer vision algorithms, near infrared spectroscopy and machine learning algorithms.

BACKGROUND: Beer quality is mainly defined by its colour, foamability and foam stability, which are influenced by the chemical composition of the product such as proteins, carbohydrates, pH and alcohol. Traditional methods to assess specific chemical compounds are usually time-consuming and costly. This study used rapid methods to evaluate 15 foam and colour-related parameters using a robotic pourer (RoboBEER) and chemical fingerprinting using near infrared spectroscopy (NIR) from six replicates of 21 beers from three types of fermentation. Results from NIR were used to create partial least squares regression (PLS) and artificial neural networks (ANN) models to predict four chemometrics such as pH, alcohol, Brix and maximum volume of foam. RESULTS: The ANN method was able to create more accurate models (R2 = 0.95) compared to PLS. Principal components analysis using RoboBEER parameters and NIR overtones related to protein explained 67% of total data variability. Additionally, a sub-space discriminant model using the absorbance values from NIR wavelengths resulted in the successful classification of 85% of beers according to fermentation type. CONCLUSION: The method proposed showed to be a rapid system based on NIR spectroscopy and RoboBEER outputs of foamability that can be used to infer the quality, production method and chemical parameters of beer with minimal laboratory equipment. © 2017 Society of Chemical Industry.

Improved quantification of important beer quality parameters based on nonlinear calibration methods applied to FT-MIR spectra.

During the production process of beer, it is of utmost importance to guarantee a high consistency of the beer quality. For instance, the bitterness is an essential quality parameter which has to be controlled within the specifications at the beginning of the production process in the unfermented beer (wort) as well as in final products such as beer and beer mix beverages. Nowadays, analytical techniques for quality control in beer production are mainly based on manual supervision, i.e., samples are taken from the process and analyzed in the laboratory. This typically requires significant lab technicians efforts for only a small fraction of samples to be analyzed, which leads to significant costs for beer breweries and companies. Fourier transform mid-infrared (FT-MIR) spectroscopy was used in combination with nonlinear multivariate calibration techniques to overcome (i) the time consuming off-line analyses in beer production and (ii) already known limitations of standard linear chemometric methods, like partial least squares (PLS), for important quality parameters Speers et al. (J I Brewing. 2003;109(3):229-235), Zhang et al. (J I Brewing. 2012;118(4):361-367) such as bitterness, citric acid, total acids, free amino nitrogen, final attenuation, or foam stability. The calibration models are established with enhanced nonlinear techniques based (i) on a new piece-wise linear version of PLS by employing fuzzy rules for local partitioning the latent variable space and (ii) on extensions of support vector regression variants (𝜖-PLSSVR and ν-PLSSVR), for overcoming high computation times in high-dimensional problems and time-intensive and inappropriate settings of the kernel parameters. Furthermore, we introduce a new model selection scheme based on bagged ensembles in order to improve robustness and thus predictive quality of the final models. The approaches are tested on real-world calibration data sets for wort and beer mix beverages, and successfully compared to linear methods, showing a clear out-performance in most cases and being able to meet the model quality requirements defined by the experts at the beer company. Figure Workflow for calibration of non-Linear model ensembles from FT-MIR spectra in beer production .

Screening for new brewing yeasts in the non-Saccharomyces sector with Torulaspora delbrueckii as model.

This study describes a screening system for future brewing yeasts focusing on non-Saccharomyces yeasts. The aim was to find new yeast strains that can ferment beer wort into a respectable beer. Ten Torulaspora delbrueckii strains were put through the screening system, which included sugar utilization tests, hop resistance tests, ethanol resistance tests, polymerase chain reaction fingerprinting, propagation tests, amino acid catabolism and anabolism, phenolic off-flavour tests and trial fermentations. Trial fermentations were analysed for extract reduction, pH drop, yeast concentration in bulk fluid and fermentation by-products. All investigated strains were able to partly ferment wort sugars and showed high tolerance to hop compounds and ethanol. One of the investigated yeast strains fermented all the wort sugars and produced a respectable fruity flavour and a beer of average ethanol content with a high volatile flavour compound concentration. Two other strains could possibly be used for pre-fermentation as a bio-flavouring agent for beers that have been post-fermented by Saccharomyces strains as a consequence of their low sugar utilization but good flavour-forming properties.

Predictive analysis of beer quality by correlating sensory evaluation with higher alcohol and ester production using multivariate statistics methods.

Sensory evaluation is regarded as a necessary procedure to ensure a reproducible quality of beer. Meanwhile, high-throughput analytical methods provide a powerful tool to analyse various flavour compounds, such as higher alcohol and ester. In this study, the relationship between flavour compounds and sensory evaluation was established by non-linear models such as partial least squares (PLS), genetic algorithm back-propagation neural network (GA-BP), support vector machine (SVM). It was shown that SVM with a Radial Basis Function (RBF) had a better performance of prediction accuracy for both calibration set (94.3%) and validation set (96.2%) than other models. Relatively lower prediction abilities were observed for GA-BP (52.1%) and PLS (31.7%). In addition, the kernel function of SVM played an essential role of model training when the prediction accuracy of SVM with polynomial kernel function was 32.9%. As a powerful multivariate statistics method, SVM holds great potential to assess beer quality.

The prevalence and impact of Fusarium head blight pathogens and mycotoxins on malting barley quality in UK.

Fusarium head blight (FHB) caused by Fusarium and Microdochium species can significantly affect the yield of barley grain as well as the quality and safety of malt and beer. The present study provides new knowledge on the impacts of the FHB pathogen complex on the malting and brewing quality parameters of naturally infected barley. Quantitative real-time PCR and liquid chromatography double mass spectrometry were used to quantify the predominant FHB pathogens and Fusarium mycotoxins, respectively, in commercially grown UK malting barley samples collected between 2007 and 2011. The predominant Fusarium species identified across the years were F. poae, F. tricinctum and F. avenaceum. Microdochium majus was the predominant Microdochium species in 2007, 2008, 2010 and 2011 whilst Microdochium nivale predominated in 2009. Deoxynivalenol and zearalenone quantified in samples collected between 2007 and 2009 were associated with F. graminearum and F. culmorum, whilst HT-2 and T-2, and nivalenol in samples collected between 2010 and 2011 correlated positively with F. langsethiae and F. poae, respectively. Analysis of the regional distribution and yearly variation in samples from 2010 to 2011 showed significant differences in the composition of the FHB species complex. In most regions (Scotland, the South and North of England) the harvest in 2010 had higher concentrations of Fusarium spp. than in 2011, although no significant difference was observed in the Midlands between the two years. Microdochium DNA was significantly higher in 2011 and in the North of England and Scotland compared to the South or Midlands regions. Pathogens of the FHB complex impacted negatively on grain yield and quality parameters. Thousand grain weight of malting barley was affected significantly by M. nivale and M. majus whilst specific weight correlated negatively with F. avenaceum and F. graminearum. To determine the impact of sub-acute infections of the identified Fusarium and Microdochium species on malting and brewing quality of naturally infected samples, selected malting barley cultivars (Optic, Quench and Tipple) were micromalted and subjected to malt and wort analysis of key quality parameters. F. poae and M. nivale decreased germinative energy and increased water sensitivity of barley. The fungal biomass of F. poae and F. langsethiae correlated with increased wort free amino nitrogen and with decreased extract of malt. DNA of M. nivale correlated with increased malt friability as well as decreased wort filtration volume. The findings of this study indicate that the impact of species such as the newly emerging F. langsethiae, as well as F. poae and the two non-toxigenic Microdochium species should be considered when evaluating the quality of malting barley.

[Alcoholism around the turn of the 20th century: the Belgian positions in European debates]. / L'alcoolisme au tournant du XXe siècle: les positions belges dans les débats européens.

In Europe, between 1880 and 1914, the alcoolism, one of the three social ills, represents more than ever a concern among the society's leaders against the ravages it causes in their working class. In this context, two schools of "anti-alcoholism" clash to policy matters: to prevent to only spirits or any form of alcohol beverage. Belgium, land of beer, forms an integral part of the debate...

An empirical evaluation of the US Beer Institute's self-regulation code governing the content of beer advertising.

OBJECTIVES: We evaluated advertising code violations using the US Beer Institute guidelines for responsible advertising. METHODS: We applied the Delphi rating technique to all beer ads (n = 289) broadcast in national markets between 1999 and 2008 during the National Collegiate Athletic Association basketball tournament games. Fifteen public health professionals completed ratings using quantitative scales measuring the content of alcohol advertisements (e.g., perceived actor age, portrayal of excessive drinking) according to 1997 and 2006 versions of the Beer Institute Code. RESULTS: Depending on the code version, exclusion criteria, and scoring method, expert raters found that between 35% and 74% of the ads had code violations. There were significant differences among producers in the frequency with which ads with violations were broadcast, but not in the proportions of unique ads with violations. Guidelines most likely to be violated included the association of beer drinking with social success and the use of content appealing to persons younger than 21 years. CONCLUSIONS: The alcohol industry's current self-regulatory framework is ineffective at preventing content violations but could be improved by the use of new rating procedures designed to better detect content code violations.

Effects of worts treated with proteases on the assimilation of free amino acids and fermentation performance of lager yeast.

The objective of this study was to investigate the changes in free amino acids (FAA) composition by supplementing three commercial proteases (Neutrase, Flavorzyme and Protamex) at the beginning of wort mashing, and monitoring the effects on the assimilation pattern of FAA and fermentation performance of lager yeast (Saccharomyces pastorianus) during normal and high gravity fermentations. Proteases supplementation significantly improved the extract yield and FAA level of mashed worts. Normal gravity worts treated with Flavorzyme and Neutrase exhibited higher fermentability, ethanol production and flavor volatiles concentration compared to the control worts, while these beneficial effects were observed in high gravity worts treated with Protamex and Neutrase. The reason for the above results is proposed to be the change in the assimilation pattern of FAA in lager yeast with increased wort gravity, especially for the improved assimilation ratios of Leu, Arg, Phe, His, Asp and Val. In normal gravity fermentations, there were strong correlations between the assimilation amounts of Lys, Leu, Arg and His and fermentability, while in high gravity fermentations, these good correlations were found with only Lys and His. The present study suggested that optimizing the composition of FAA by supplementing proteases during wort mashing was beneficial to beer brewing for improving fermentation performance of lager yeast and flavor volatiles formation.

Construction of self-cloning bottom-fermenting yeast with low vicinal diketone production by the homo-integration of ILV5.

The vicinal diketones (VDK), such as diacetyl and 2,3-pentandione, impart an unpleasant butter-like flavour to beer. Typically, these are required to be reduced below the flavour thresholds during the maturation (lagering) stages of the brewing process. To shorten beer maturation time, we constructed a self-cloning, bottom-fermenting yeast with low VDK production by integrating ILV5, a gene encoding a protein that metabolizes α-acetolactate and α-aceto-α-hydroxybutyrate (precursors of VDK). A DNA fragment containing Saccharomyces cerevisiae-type ILV5 was inserted upstream of S. cerevisiae-type ILV2 in bottom-fermenting yeast to construct self-cloning strains with an increased copy number of ILV5. Via transformation, ILV2 was replaced with the sulfometuron methyl (SM) resistance gene SMR1B, which differs by a single nucleotide, to create SM-resistant transformants. The wort fermentation test, using the SC-ILV5-homo inserted transformant, confirmed a consecutive reduction in VDK and a shortening period during which VDK was reduced to within the threshold. The concentrations of ethyl acetate, isoamyl acetate, isoamyl alcohol, 1-propanol, isobutyl alcohol and active isoamyl alcohol (flavour components) were not changed when compared with the parent strain. We successfully constructed self-cloning brewer's yeast in which SC-ILV5 was homo-inserted. Using the transformed yeast, the concentration of VDK in fermenting wort was reduced, whereas the concentrations of flavour components were not affected. This genetically stable, low VDK-producing, self-cloning bottom-fermenting yeast would contribute to the shortening of beer maturation time without affecting important flavour components produced by brewer's yeast.

Confirmation of brand identity of a Trappist beer by mid-infrared spectroscopy coupled with multivariate data analysis.

Authentication of foods is of importance both to consumers and producers for e.g. confidence in label descriptions and brand protection, respectively. The authentication of beers has received limited attention and in most cases only small data sets were analysed. In this study, Fourier-transform infrared attenuated total reflectance (FT-IR ATR) spectroscopy was applied to a set of 267 beers (53 different brands) to confirm claimed identity for samples of a single beer brand based on their spectral profiles. Skewness-adjusted robust principal component analysis (ROBPCA) was deployed to detect outliers in the data. Subsequently, extended canonical variates analysis (ECVA) was used to reduce the dimensionality of the data while simultaneously achieving maximum class separation. Finally, the reduced data were used as inputs to various linear and non-linear classifiers. Work focused on the specific identification of Rochefort 8° (a Trappist beer) and both direct and indirect (using an hierarchical approach) identification strategies were studied. For the classification problems Rochefort vs. non-Rochefort, Rochefort 8° vs. non-Rochefort 8° and Rochefort 8° vs. Rochefort 6° and 10°, correct prediction abilities of 93.8%, 93.3% and 97.3%, respectively were achieved.

Brewhouse-resident microbiota are responsible for multi-stage fermentation of American coolship ale.

American coolship ale (ACA) is a type of spontaneously fermented beer that employs production methods similar to traditional Belgian lambic. In spite of its growing popularity in the American craft-brewing sector, the fermentation microbiology of ACA has not been previously described, and thus the interface between production methodology and microbial community structure is unexplored. Using terminal restriction fragment length polymorphism (TRFLP), barcoded amplicon sequencing (BAS), quantitative PCR (qPCR) and culture-dependent analysis, ACA fermentations were shown to follow a consistent fermentation progression, initially dominated by Enterobacteriaceae and a range of oxidative yeasts in the first month, then ceding to Saccharomyces spp. and Lactobacillales for the following year. After one year of fermentation, Brettanomyces bruxellensis was the dominant yeast population (occasionally accompanied by minor populations of Candida spp., Pichia spp., and other yeasts) and Lactobacillales remained dominant, though various aerobic bacteria became more prevalent. This work demonstrates that ACA exhibits a conserved core microbial succession in absence of inoculation, supporting the role of a resident brewhouse microbiota. These findings establish this core microbial profile of spontaneous beer fermentations as a target for production control points and quality standards for these beers.

Isolation of a virulent Lactobacillus brevis phage and its application in the control of beer spoilage.

Beer quality can be compromised by the growth of certain lactobacilli, in particular Lactobacillus brevis and Lactobacillus plantarum, and various strategies have been used to control such bacterial spoilage. Biocontrol by means of bacteriophage is a reemerging approach for the suppression of spoilage bacteria in food and beverage matrices. A virulent phage capable of infecting L. brevis beer-spoilage strains was isolated and morphologically assessed by electron microscopy. The myophage SA-C12 was shown to be stable in beer and capable of controlling the growth of its host, L. brevis strain 56, in commercial beer. The results of this study indicate that bacteriophage-based treatments may be used as an alternative and natural strategy for the control of bacterial contamination of beer.

Influence of barley variety, timing of nitrogen fertilisation and sunn pest infestation on malting and brewing.

BACKGROUND: This paper presents a multivariate approach to investigate the influence of barley variety, timing of nitrogen fertilisation and sunn pest infestation on malting and brewing. Four spring and two winter barley varieties were grown in one location in southern Europe. Moreover, one of the spring varieties was infested with sunn pest, in order to study the effects of this pest on malting quality, and subjected to different nitrogen fertilisation timing regimes. The samples were micromalted, mashed, brewed and analysed. RESULTS: The data showed that even though the two winter barleys seemed to be the best regarding their physical appearance (sieving fraction I + II > 82%), this superiority was not confirmed in the malt samples, which showed low values of Hartong extract (27.1%) and high values of pH (6.07-6.11) and ß-glucan content (12.5-13.2 g kg(-1)), resulting in low-quality beers. The barley sample subjected to postponed fertilisation had a total nitrogen content (19.5 g kg(-1) dry matter) exceeding the specification for malting barley and gave a beer with a low content of free amino nitrogen (47 mg L(-1)) and high values of viscosity (1.99 cP) and ß-glucan content (533 mg L(-1)). The beer obtained from the barley sample subjected to pest attack had good quality parameters. CONCLUSION: All spring barleys gave well-modified malts and consequently beers of higher quality than the winter barleys. Moreover, postponed fertilisation was negatively related to the quality of the final beer, and sunn pest infestation did not induce important economic losses in the beer production chain.

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.

Occurrence of ochratoxin A in wine and beer samples from China.

A total of 125 wine and beer samples, including 42 white, 63 red wine and 20 beer samples, originating from several areas of China were analyzed for ochratoxin A (OTA). An analytical method based on immunoaffinity column (IAC) for clean-up and high performance liquid chromatography with fluorescence detection (HPLC-FD) was used to determine OTA. Positive results were further confirmed by LC-MS-MS. OTA was detected in 22 (17.6%) samples at levels of 0.02-1.18 ng/ml, which were below the EU maximum limit. The mean OTA concentration in red wine was slightly higher than in white wine. This study showed that OTA occurs in wine and beer in China but at levels that pose no danger of significant human exposure to OTA from this source.