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Brewing practice uses the same yeast to inoculate the following fermentation (repitching). Saccharomyces pastorianus , used to produce Lager beer, is widely reused, not changing its fermentation performance. However, S. cerevisiae , used to produce Ale beer, is partial or not even reused, due to its poor performance. It is hypothesized that cells modulate their wall polysaccharides to increase the cell-wall strength. In this work industrial S. cerevisiae and S. pastorianus brewer's spent yeasts with different repitching numbers were studied. Glucans were the main component of S. cerevisiae whereas mannoproteins were abundant in S. pastorianus. The major changes were noticed on glucans of both species, β 1,3-glucans decrease more pronounced in S. cerevisiae. The increase of α 1,4-Glc, related with osmotolerance, was higher in S. cerevisiae while β 1,4-Glc, related with cell-wall strength, had a small increase. In addition, these structural details showed different binding profiles to immune receptors, important to develop tailored bioactive applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Yeast flocculation is a natural event that led to get clear and stable products in brewing and another fermented products. However, when it is unsuccessful is necessary to employ filtration processes. The flocculin proteins, coded for family FLO genes, are responsible for the flocculation. In this study, we analyzed the transcriptome of two Saccharomyces pastorianus yeast strains. To get information about isoforms, molecular size and expression (in fpkm) of flocculins, we analyzed the genetic expression of FLO1, FLO5, FLO8, FLO9, FLO10 and FLO11 genes. Fermentations performed under standard conditions for lager beer kind and after two, and five fermentation days, samples taken and RNA purified. Our results showed differences at molecular size than previously reported. These ones could be responsible for the flocculation capacity of the strains. The structural analysis of the flocculins allows locating the difference in the domain between the brewing strains and the reference strains. [ABSTRACT FROM AUTHOR]

Very high gravity brewing can achieve effective energy saving and significant emission reduction, and thereby has been progressively applied in beer industries. However, the yeast cells encountered multiple environmental stresses during very high gravity brewing, resulting in the sluggish fermentation. To overcome this issue, a practical strategy, that is increasing the fermentation temperature, has been used. However, to which extent the temperature could be increased and whether the higher temperature would influence the viability and vitality of the cells that would be re-used for the next run of fermentation remains unclear. In this study, we compare the fermentation performance of three lager yeast under different temperatures (11 °C, 15 °C, 18 °C). Yeast cell growth and fermentation rate analysis show that a higher temperature can indeed increase the fermentation rates. However, the taste value and volatile compounds analysis indicated that different temperatures have also changed the flavor fingerprint dramatically. Meanwhile, lower cell viability and flocculation ability could be caused by the higher temperature. Hence, increasing the fermentation temperature in a reasonable range is an available method for coping sluggish problem in very high gravity brewing. • The impacts of different temperatures on VHG of lager beer was made. • E-tongue and GC-MS were applied to analysis the flavor with lager beer. • Yeast characters were discussed along with the fermentation performance. • Increasing temperature slightly is an available method for sluggish problem. [ABSTRACT FROM AUTHOR]

Lager beer with high content of cyclic adenosine monophosphate (c-AMP) and strong antioxidant activity was produced by supplementing six jujube cultivars (Ziziphus Jujuba cv. Hetian , Muzao , Huizao , Goutou , Jinsixiaozao , and Banzao) as adjuncts. Jujube supplementation significantly increased total phenolic and flavonoids contents of final beers, and therefore improved antioxidant activities based on DPPH, ABTS and FRAP methods, especially for Banzao supplementation, exhibiting the highest antioxidant activities, increasing by 31.00%, 20.81% and 43.66%, respectively, which were positively correlated with protocatechuic acid, p-coumaric acid and rutin levels. Furthermore, hierarchical cluster analysis revealed that jujube supplementation significantly influenced flavor formation in final beers. There were 17 new volatile compounds formation after jujube supplementation, including one alcohol, 11 esters, two acids and three aldehydes, suggesting the improved complexity of beer flavor. In addition, high contents of c-AMP ranging from 4.02 to 15.14 μg/mL were observed in final beers fermented by jujube supplementation, endowing beer with a new health function. [Display omitted] • Jujube was suggested as a promising adjunct for beer brewing. • Beer fermented by jujube supplementation exhibited stronger antioxidant capacity. • Jujube adjunct improved protocatechuic acid, p-comaric acid, and rutin contents. • Beer fermented by jujube supplementation exhibited high c-AMP level. • Jujube supplementation improved the aroma complexity of beer. [ABSTRACT FROM AUTHOR]

Five commercial lager beers were used to investigate the evolution of antioxidant activity and ageing compounds during storage. The relationships between antioxidant activity and ageing compounds were clarified by principal component analysis ( PCA). Results showed that total phenolic content ( TPC) and antioxidant activities of beers evaluated by different assays gradually decreased by 16.08-22.71% (average of 18.56%) and 1.99-78.79% (averages of 24.44-70.50%), which was accompanied by 100.50-269.35% (average of 178.77%) and 11.11-57.14% (average of 28.73%) of increases in total ageing compounds and thiobarbituric acid ( TBA) value, respectively, during 6 months of storage at 25 °C. Results from PCA elucidated that there were negative correlations between antioxidant activities and ageing compounds of beers during storage, and satisfactory discrimination among beers with different storage time could be achieved on the basis of antioxidant activities and typical ageing compounds selected. [ABSTRACT FROM AUTHOR]

This article examines the historical origins of bland American beer. The US was not strongly associated with a particular beer type until German immigrants popularised lager beer. Lager, refreshing and mildly intoxicating, met the demands of America's growing working class. Over time, American lager became lighter and blander. This article emphasises America's uncommonly strong temperance movement, which put the industry on the defensive. Brewers pushed their product as ‘the beverage of moderation,’ and consumers sought out light, relatively non-intoxicating beers. The recent ‘craft beer revolution’ is explained as a backlash aided by a changing consumer culture and improved information technology. [ABSTRACT FROM AUTHOR]

A new fast and sensitive method based on on-line solid-phase extraction on a fused-core precolumn coupled to liquid chromatography with fluorescence detection has been developed for ochratoxin A (OTA) and citrinin (CIT) determination in lager beer samples. Direct injection of 100 μL filtered beer samples into an on-line SPE-HPLC system enabled fast and effective sample extraction including separation in less than 6 min. Preconcentration of OTA and CIT from beer samples was performed on an Ascentis Express RP C18 guard column (5 × 4.6 mm), particle size 2.7 μm, with a mobile phase of methanol/0.5 % aqueous acetic acid pH 2.8 (30:70, v/v) at a flow rate of 2.0 mL min. The flow switch from extraction column to analytical column in back-flush mode was set at 2.0 min and the separation was performed on the fused-core column Ascentis Express Phenyl-Hexyl (100 × 4.6 mm), particle size 2.7 μm, with a mobile phase acetonitrile/0.5 % aqueous acetic acid pH 2.8 in a gradient elution at a flow rate of 1.0 mL min and temperature of 50 °C. Fluorescence excitation/emission detection wavelengths were set at 335/497 nm. The accuracy of the method, defined as the mean recoveries of OTA and CIT from light and dark beer samples, was in the range 98.3-102.1 %. The method showed high sensitivity owing to on-line preconcentration; LOQ values were found to be 10 and 20 ng L for OTA and CIT, respectively. The found values of OTA and CIT in all tested light, dark and wheat beer samples were significantly below the maximum tolerable limits (3.0 μg kg for OTA and 2000 μg kg for CIT) set by the European Union. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Saccharomyces interspecies hybrids are critical biocatalysts in the fermented beverage industry, including in the production of lager beers, Belgian ales, ciders, and cold-fermented wines. Current methods for making synthetic interspecies hybrids are cumbersome and/or require genome modifications. We have developed a simple, robust, and efficient method for generating allotetraploid strains of prototrophic Saccharomyces without sporulation or nuclear genome manipulation. S. cerevisiae × S. eubayanus , S. cerevisiae × S. kudriavzevii , and S. cerevisiae × S. uvarum designer hybrid strains were created as synthetic lager, Belgian, and cider strains, respectively. The ploidy and hybrid nature of the strains were confirmed using flow cytometry and PCR-RFLP analysis, respectively. This method provides an efficient means for producing novel synthetic hybrids for beverage and biofuel production, as well as for constructing tetraploids to be used for basic research in evolutionary genetics and genome stability. [ABSTRACT FROM AUTHOR]

Beer is one from the most popular alcoholic beverages worldwide. For consumer acceptance, a significant factor is its flavour and taste; carbonyl compounds play an important role as indicators of the deterioration of flavour and aroma in beers. The aim of this study was to characterize differences in the carbonyl profile from Czech and Spanish beers, based on tradition and modern technology, respectively. Headspace solid-phase microextraction and gas-chromatography mass spectrometry were used to compare lager beers. The technique of on-fibre derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBOA) was used to achieve satisfactory recovery and sensitivity. Statistical factor analysis showed three principal components, two of them explaining more than 79% of the variability and these results were related to ANOVA-significant difference analysis based on the country of origin. These two factors were related to Strecker aldehydes and Maillard products. PCA analysis scatterplot confirmed a significant difference between the Spanish and Czech beers, particularly with regard to the content of diacetyl and (E) -non-2-enal. [ABSTRACT FROM AUTHOR]

The aim of this research was to create mathematical models for describing the changes in beer properties by using two chemometric methods applied on the experimental data. The models are intended to be useful and trustworthy for calculating four beer properties based on three easily measured ones. For that purpose, lager and malt beer were packaged in glass bottles, while lager beer was also packaged in polyethylene terephthalate (PET). Samples were placed at room temperature in the dark for 6 months. Fifteen physical and chemical properties of the beer were measured before bottling, immediately after bottling and once per month for the next 6 months. Standard MEBAK and Analytica-EBC methods of analysis were applied. During the 6 month period, seven properties changed >1%. Two partial least squares regression methods [polynomial regression, partial least squares regression with polynomial regression (PLSR-PR) and response surface method (PLSR-RSM)] were used for modelling the relationships amongst multivariate measurements. Models with high statistical significance were determined and two PLSR methods were compared. Both chemometric methods were found to be suitable for modelling physical and chemical changes in the beers during their commercial shelf-life. The PLS-RSM method was found to be the more precise and confident method in describing property changes for lager and malt beer in glass bottles, while the polynomial regression model was found to be better for the lager beer packaged in PET. The R2 values determined for polynomial regression model were up to 0.939, while for the random surface method model the values were up to 1.000. Copyright © 2016 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]