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The brewing industry is constantly evolving, driven by the quest for novel flavours and fermentation characteristics that cater to evolving consumer preferences. This study explores the genetic and phenotypic diversity of European farmhouse yeasts, traditionally used in rural brewing practices and maintained outside of pure culture industrial yeast selection. We isolated landrace brewing yeast strains from diverse geographical locations across Europe, including Norway, Lithuania, Latvia, and Russia, and also included African farmhouse brewing strains from Ghana. Our genomic analysis using long-read and short-read whole genome sequencing uncovered a genetically distinct group that diverges from industrial brewing yeasts. This group, which is closely related to ale brewing strains, is preliminarily named the 'European Farmhouse' group and shows greater predicted admixture from Asian fermentation strains. Through genomic and phenotypic analyses, including flavour metabolite analysis via headspace gas chromatography-mass spectrometry, sugar metabolite analysis via high-performance liquid chromatography, and wort fermentation analysis, we found a broad spectrum of fermentation capabilities, from rapid and efficient fermentation to unique aroma and flavour compound profiles, potentially offering novel traits for brewing applications. This study highlights the importance of preservation of brewing cultural heritage knowledge and resources including yeast cultures. Key points: • A large set of geographically diverse farmhouse brewing strains were characterized • Norwegian and Baltic farmhouse brewing strains form a distinct genetic group • Farmhouse strains show considerable diversity in fermentation and flavour formation [ABSTRACT FROM AUTHOR]

Prodigiosin (PG)—a molecule with promising applications in many fields—was effectively biosynthesized in this study using a novel and eco-friendly fermentation substrate—i.e., beer brewing by-product (BBB). It was confirmed as a nutrient-rich substrate source of protein (22.18%), ash (10.1%), carbohydrate (1.98%), sugar, and abundant mineral elements. The cultural medium with a newly designed formula on a small flask containing 1.25% BBB/Casein (9/1), 0.025% FeSO4, and 0.125% Na2HPO4 for a notable PG yield achieved 6230 mg/L after 48 h. PG production on a bioreactor system also enhanced yield by 1.16 folds (reaching 7220 mg/L) and shortened fermentation time (only taking 10 h). This pure pigment was isolated and identified by analyzing UV/vis absorption, MALDI-TOF MS, and HPLC. The obtained PG was used for antifungal tests. Notably, in this work, most of PG's pathogen fungal inhibition activity are new findings. Of those, PG showed the most positive effect on Colletotrichum gloeosporioides F05 strain (causing on sweet potato roots) with inhibition rates of mycelial growth and spore germination achieved at 47 and 57%, respectively. In particular, PG also reduced resistance and wholly inhibited mycelium growth germinating from spores. Furthermore, PG showed the good interaction ability with multiple target proteins (CDC42, CYP51, CAS2, Pectate lyase B, and Beta tubulin) inhibiting C. gloeosporioides via docking simulation. The results of this study revealed useful scientific information related to the novel application of BBB in PG production and the new PG's effects in the management of fungal pathogens in crops. [ABSTRACT FROM AUTHOR]

Beer is made via the fermentation of an aqueous extract predominantly composed of malted barley flavoured with hops. The transforming microorganism is typically a single strain of Saccharomyces cerevisiae, and for the majority of major beer brands the yeast strain is a unique component. The present yeast used to make Guinness stout brewed in Dublin, Ireland, can be traced back to 1903, but its origins are unknown. To that end, we used Illumina and Nanopore sequencing to generate whole-genome sequencing data for a total of 22 S. cerevisiae yeast strains: 16 from the Guinness collection and 6 other historical Irish brewing. The origins of the Guinness yeast were determined with a SNP-based analysis, demonstrating that the Guinness strains occupy a distinct group separate from other historical Irish brewing yeasts. Assessment of chromosome number, copy number variation and phenotypic evaluation of key brewing attributes established Guinness yeast-specific SNPs but no specific chromosomal amplifications. Our analysis also demonstrated the effects of yeast storage on phylogeny. Altogether, our results suggest that the Guinness yeast used today is related to the first deposited Guinness yeast; the 1903 Watling Laboratory Guinness yeast. A genomic analysis of 22 S. cereviseae yeast strains used in beer brewing suggest that yeast used to brew Guinness form a distinct evolutionary sub-clade, and that the modern-day Guinness yeast is closely related to the 1903 Watling Laboratory Guinness yeast. [ABSTRACT FROM AUTHOR]

The brewing industry has experienced a significant boom in recent years through the emergence of, on the one hand, craft breweries that produce beers with unique organoleptic characteristics, and, on the other hand, the brewing of a significant number of beers using hybridized or genetically modified microorganisms with the aim of improving both the brewing processes and the final products. This review covers the influence from yeast strains on the organoleptic properties of the final beers and also the main hybridization and genetic modification methods applied to such yeast strains with the aim of improving the sensory characteristics of the product obtained and/or the brewing process. Different approaches to the phenotypic modification of the yeasts used in beer brewing have arisen in recent years. These are dealt with in this work, with special emphasis on the methodology followed as well as on the effects of the same on the brewing process and/or on the final product. [ABSTRACT FROM AUTHOR]

In the recent years, beer brewers are experimenting with using various substrates, other than traditional barley malt, water, hops, and yeast for beer production, because new adjuncts to the beer brewing can add new sensory and functional properties to this beverage. Novel potatoes with purple or red-colour flesh are a good and cheap starch source and are rich in bioactive components, which could increase the nutritive value of the produced beer. The aim of the study was to determine whether some part of barley malt can be replaced by the potatoes of purple-colour flesh and assessment of properties of such beer. Beer samples showed increased antioxidant activity, higher concentration of anthocyanins and polyphenol compounds, as well as modified composition of volatiles and lower ethanol content. Beer produced with the addition of 30% of purple potatoes showed acceptable organoleptic qualities in the sensory analysis. [ABSTRACT FROM AUTHOR]

To assess the impact of black-colored grain on Alternaria mycotoxin concentrations in different stages of the brewing process, brewing experiments were conducted in a microscale brewhouse. Different mixtures of visually unaffected and black-colored batches of two malt samples were used, which were obtained by an optical sorting device. The 13 Alternaria mycotoxins alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), tentoxin (TEN), alterperylenol (ALTP), altertoxins I and II (ATX I and II), altenuene (ALT) as well as the modified forms AOH-3-glucoside (AOH-3-G), AOH-9-glucoside (AOH-9-G), AME-3-gluoside (AME-3-G), AOH-3-sulfate (AOH-3-S) and AME-3-sulfate (AME-3-S) were analyzed in each processing step by liquid chromatography–tandem mass spectrometry (LC–MS/MS), and the toxin concentrations were balanced over the whole brewing process. Fungal DNA content in the starting material (mixtures) was determined by quantitative real-time polymerase chain reaction (qPCR). In this study, TeA was the only toxin to migrate into the final beer, while the AOH, AME, TEN, ALTP and ATX I toxins were mainly found in the spent grains. The observance of AOH-3-S and AME-3-S in some processing steps also showed the possibility of modification reactions during brewing. Furthermore, no distinct correlations between the fungal DNA and the analyzed mycotoxins could be observed in the starting material, while the amount of black colored grains only impacted toxin concentrations in one of the two used malt samples. Nevertheless, it was shown that optical sorting of malt batches might be a useful tool for the malting and brewing industry to prevent elevated mycotoxin concentrations. [ABSTRACT FROM AUTHOR]

The aim of the paper was to determine potential of using grape pulp, marc and must in the beer production process. Samples were fermented using non-Saccharomyces yeasts (Dekkera bruxellensis 3429, Metschnikowia pulcherrima MG970690) and Saccharomyces cerevisiae Safale US-05 was used as a control. Grape marc was obtained by pressing grape must with a press. Subsequently, the grape marc, must and pulp were pasteurized and, together with wort, volumetrically introduced into fermentation flasks for fermentation. Mass changes taking place during the process were analyzed. Real extract, alcohol, free amino nitrogen (FAN) content, pH, color, sugars and organic acid profile were determined in obtained beers. The research has shown that the yeasts Dekkera bruxellensis 3429 fermented similarly to Saccharomyces cerevisiae Safale US-05. The yeast D. bruxellensis 3429 produced more alcohol in the finished beers in most cases and assimilated more FAN than M. pulcherrima MG970690. The D. bruxellensis 3429 strain most effectively used L-malic acid. [ABSTRACT FROM AUTHOR]

Non-conventional yeasts can be isolated from a wide range of environmental sources and are often found in the beverage industry in mixed fermentations, in which the microbial community is usually not fully known. However, it is important to know the compositions of these starter cultures because in addition to enabling reproducibility during fermentation, other properties can be discovered. Thus, the objective of this work was to identify and characterize non-conventional yeasts isolated from the environment, evaluating their probiotic potential and possible use in beer brewing. Isolates were obtained from flowers, fruits, leaves and mixed-fermentation beers, with the species being identified by PCR. Yeasts with promising activity were evaluated regarding their growth under different pHs, temperature and the presence of organic acids. To explore probiotic potential, in vitro tests were performed for antimicrobial activity and co-aggregation with food-spoiling microorganisms, auto-aggregation and survival in simulated gastrointestinal tract conditions. In this study, Pichia kluyveri (LAR001), Hanseniaspora uvarum (PIT001) and Candida intermedia (ORQ001) were selected among 20 isolates for further study. P. kluyveri was the only strain that tolerated pH 2.5. Lactic acid was not inhibitory, but acetic acid and incubation at 37 °C had partially inhibitory effects on yeast growth. All yeasts tolerated α-acids from hops and up to 1% NaCl. Our results also suggest that these isolates are able to adhere to intestinal cells and positively influence the host to combat pathogens, as they showed auto-aggregation rates > 99% and antagonistic activity to pathogenic bacteria. The yeasts tolerated gastric environment conditions, but were more sensitive to pancreatic conditions. We conclude that these non-conventional yeasts have probiotic potential and promising application in beer fermentation. [ABSTRACT FROM AUTHOR]

Cereals for beer brewing have long been dominated by barley (Hordeum vulgare) and wheat (Triticum aestivum). Tritordeum, a novel amphiploid hybrid of South American barley (Hordeum chilense) and durum wheat (Triticum turgidum), is considered an interesting alternative. The aim of the study was to investigate how different malting regimes influence the malt quality of tritordeum from a beer brewing perspective. Tritordeum malt produced by a double wet steep regime with 6 days of germination exceeded commercial barley malt in amylase activity and free amino nitrogen content (FAN) while achieving equal levels of extract. A triple wet steep regime was not as successful, only yielding an increase in β-glucanase activity. FAN, extract, acidity and amylase activity in tritordeum sweet worts generally increased with germination, with all quality parameters except β-amylase activity plateauing after 5 days. Worts made from tritordeum malts generally had higher iron levels than worts made from the barley malt. A laboratory-scale brew of the best experimental tritordeum malt had the same alcohol content as the barley malt reference, confirming its potential as an alternative raw material. Elevated FAN and iron contents were retained throughout the brewing process. [ABSTRACT FROM AUTHOR]

There is a relationship between antioxidant activity and ageing stability of beer. The high-throughput antioxidant capacity assays ORAC and FRAP, which rely on specific reaction mechanisms, are validated as an addition to the established ESR-ST method with a focus on hop-derived antioxidants. Beers were brewed with systematic variations in hop variety, hop product, and the hopping regime (late hopping) to achieve sample beers varying widely in the concentrations of hop-derived antioxidants (α- and iso-α-acids, phenolic compounds). A significant positive correlation between phenolic compounds and the ORAC- and FRAP-values (p < 0.01) was found. The effect of individual resinous substances and free phenolic acids and flavonoids on the antioxidant capacity of beer (ORAC, FRAP, and ESR-ST) was proven in spiking trials. We found a correlation between the occurrence of the o-di-OH-group and the ORAC- and FRAP-values of phenolic compounds. Phenolic compounds did not react as anti- or prooxidants in the radical generation (ESR-ST). Higher concentrations of unisomerized α-acids significantly reduced ESR-signal intensity but had no significant effect on ORAC- or FRAP-values. Beers brewed with late hop addition, which yielded higher concentrations of unisomerized α-acids and phenolic compounds, had higher ORAC, FRAP-values and a reduced ESR-signal intensity. These three methods rely on different reaction principles, and therefore, different groups of hop-derived compounds act as antioxidants in these assays. A combination of the two high-throughput methods (ORAC, FRAP) and ESR-ST is advantageous for the evaluation of the antioxidant capacity of beers varying in hop-derived compounds. [ABSTRACT FROM AUTHOR]

Mashing is one of the key steps in beer brewing which influences the sensory quality of beer. Polyphenols can affect the quality and stability of beer. In pilot brewing experiments (200 l) of pale lager, the influence of the mashing on the content of polyphenols in beer was investigated for four variants, listed from the least to the most intensive: infusion (INF), single decoction (1DM), double decoction (2DM), and triple decoction (3DM). The profiles of proanthocyanidins, flavonoids, and prenylflavonoids were determined by UHPLC‒MS/MS. Antioxidant activity was measured using two methods, ARA-DPPH (1,1-dipyridyl-2-picryl hydrazyl) and RC-DCPI (2,6-dichlorophenol indophenol). The results showed a significant effect of decoction mashing on polyphenols in beer. The values of total polyphenols, reducing capacity RC-DCPI, and antiradical activity ARA-DPPH were higher for the decoction than for the infusion by 22%, 38%, and 26%, respectively. Flavanols and proanthocyanidins increased from INF to 3DM (by 16% and 38%, respectively). Even the hop-derived flavonols and prenylflavonoids increased from INF to 3DM by 10% and 37%, respectively. These results suggest that decoction mashing, especially the more intensive variants, results in a significant increase in all flavonoids in beer, with a possible benefit for the sensory stability of beer and/or the health of beer consumers. [ABSTRACT FROM AUTHOR]

Interspecies hybridization has been shown to be a powerful tool for developing and improving brewing yeast in a number of industry-relevant respects. Thanks to the popularity of heavily hopped 'India Pale Ale'-style beers, there is an increased demand from brewers for strains that can boost hop aroma. Here, we explored whether hybridization could be used to construct strains with an enhanced ability to release hop-derived flavours through β-lyase activity, which releases desirable volatile thiols. Wild Saccharomyces strains were shown to possess high β-lyase activity compared to brewing strains, however, they also produced phenolic off-flavours (POF) and showed poor attenuation. To overcome these limitations, interspecies hybrids were constructed by crossing pairs of one of three brewing and one of three wild Saccharomyces strains (S. uvarum and S. eubayanus). Hybrids were screened for fermentation ability and β-lyase activity, and selected hybrids showed improved fermentation and formation of both volatile thiols (4MMP, 3MH and 3MH-acetate) and aroma-active esters compared to the parent strains. Undesirable traits (e.g. POF) could be removed from the hybrid by sporulation. To conclude, it was possible to boost the release of desirable hop-derived thiols in brewing yeast by hybridization with wild yeast. This allows production of beer with boosted hop aroma with less hops (thus improving sustainability issues). [ABSTRACT FROM AUTHOR]

There is a growing appreciation for the role that yeast play in biotransformation of flavour compounds during beverage fermentations. This is particularly the case for brewing due to the continued popularity of aromatic beers produced via the dry-hopping process. Here, we review the current literature pertaining to biotransformation reactions mediated by fermentative yeasts. These reactions are diverse and include the liberation of thiols from cysteine or glutathione-bound adducts, as well as the release of glycosidically bound terpene alcohols. These changes serve generally to increase the fruit and floral aromas in beverages. This is particularly the case for the thiol compounds released via yeast β-lyase activity due to their low flavour thresholds. The role of yeast β-glucosidases in increasing terpene alcohols is less clear, at least with respect to fermentation of brewer's wort. Yeast acetyl transferase and acetate esterase also have an impact on the quality and perceptibility of flavour compounds. Isomerization and reduction reactions, e.g. the conversion of geraniol (rose) to β-citronellol (citrus), also have potential to alter significantly flavour profiles. A greater understanding of biotransformation reactions is expected to not only facilitate greater control of beverage flavour profiles, but also to allow for more efficient exploitation of raw materials and thereby greater process sustainability. Key points: • Yeast can alter and boost grape- and hop-derived flavour compounds in wine and beer • β-lyase activity can release fruit-flavoured thiols with low flavour thresholds • Floral and citrus-flavoured terpene alcohols can be released or interconverted [ABSTRACT FROM AUTHOR]

A historical beer, dated to the German Empire era, was recently found in northern Germany. Its chemical composition represents a unique source of insights into brewing culture of the late nineteenth century when pioneer innovations laid the foundations for industrial brewing. Complementary analytics including metabolomics, microbiological, sensory, and beer attribute analysis revealed its molecular profile and certify the unprecedented good storage condition even after 130 years in the bottle. Comparing its chemical signature to that of four hundred modern brews allowed to describe molecular fingerprints teaching us about technological aspects of historical beer brewing. Several critical production steps such as malting and germ treatment, wort preparation and fermentation, filtration and storage, and compliance with the Bavarian Purity Law left detectable molecular imprints. In addition, the aging process of the drinkable brew could be analyzed on a chemical level and resulted in an unseen diversity of hops- and Maillard-derived compounds. Using this archeochemical forensic approach, the historical production process of a culturally significant beverage could be traced and the ravages of time made visible. [ABSTRACT FROM AUTHOR]

2,2-Dibromo-3-nitrilopropionamide (DBNPA) has been used as a biocide in industrial water applications due to its instantaneous antimicrobial activity and rapid chemical breakdown. In this study, DBNPA is considered a potential alternative for antibiotics used for bacterial control during corn-to-ethanol fermentation. A method using LC/MS/MS was developed to accurately quantify DBNPA in water. When this method was applied to quantify DBNPA concentration in a fermentation matrix, DBNPA was found to be unstable and to decay rapidly, preventing validation of the method or quantitation. This method was then used to evaluate the degradation rate of DBNPA in whole stillage, which is the nonvolatile residue produced by removal of ethanol from corn-based fermentation beer by distillation through the relative decrease in measured signal. In addition, a method was developed and validated to quantify bromide, one of the degradation products of DBNPA, in whole stillage using LC/MS/MS. The degradation rate of DBNPA in whole stillage was found to display first-order kinetics with a calculated half-life of 85 min. Laboratory analytical chemistry results on DBNPA degradation were confirmed based on a bacterial viability assay in field trials. [ABSTRACT FROM AUTHOR]

Brewers' spent grain (BSG) represents the 85% of the total residue produced during the beer brewing process, with a global annual production volume exceeding 30 Mtons. The current study concerns the application of solid state fermentation (SSF) as a bioprocess where the nutritional value of BSG is improved for further use as animal feed with increased value. The investigated SSF procedure was initiated by the edible fungi Pleurotus ostreatus, which constitutes a natural source of proteins, β-glucans, and various metabolites (vitamins, nutrients, etc.). Herein, the SSF of BSG resulted in a significant increase of protein content by 49.49%, a 10-fold increase of 1,3-1,6 β-glucans, and a respective reduction of cellulose by 11.42%. The application of this method is expected to provide some useful information on the utilization of BSG as substrate for fungi-initiated SSF, a bioprocess allowing the significant reduction of the environmental impact caused by the beer brewing industry and simultaneously producing animal feed with higher protein content and improved nutritional characteristics. Such studies contribute to confront the unavailability of proteinaceous animal feed observed in the last decade. [ABSTRACT FROM AUTHOR]

Malt is an important raw material in brewing beer. With the increasing development of craft beer, brewing malt has contributed diverse colours and abundant flavours to beer. While "malty" and "worty" were commonly used to describe the malt flavour of beer, they are still inadequate. This study focused on developing of a sensory lexicon and a sensory wheel for brewing malt. Here, a total of 22 samples were used for sensory evaluation. The panels identified 53 attributes to form the lexicon of brewing malt, including appearance, flavour, taste, and mouthfeel. After consulting with the experts from the brewing industry, 46 attributes were selected from the lexicon list to construct the sensory wheel. Based on the lexicon, rate-all-that-apply analysis was used to discriminate between six samples of different malt types. The principal component analysis results showed that malt types were significantly correlated with sensory features. To further understand the chemical origin of sensory attributes, partial least squares regression analysis was used to determine the association between the aroma compounds and sensory attributes. According to the colour range and malt types, 18 samples were used for sensory descriptive analysis and volatile compounds identification. Seven main flavours were selected from the brewing malt sensory wheel. 34 aroma compounds were identified by headspace solid phase microextraction gas chromatography-mass spectrometry-olfactometry. According to the partial least squares regression results, the aroma compounds were highly correlated with the sensory attributes of the brewing malt. This approach may have practical applications in the sensory studies of other products. [ABSTRACT FROM AUTHOR]

Hops (Humulus lupulus L.) are known worldwide for their application in the food industry by providing both aroma and flavor to the beer. Considering its popularity as an indispensable brewing crop, a lot of information can be found in the literature about the bioactive compounds present in hop cones. However, current research pointed that hop application can go further than brewing. The present review updates the emerging technologies used to extract hop bioactive compounds in comparison with the conventional ones. The main characteristics, extraction conditions, and extracted compounds of these environmentally friendly extraction methods are highlighted, helping to understand their importance and industrial applications, especially considering hop phytochemicals and their potential for the food industry. In addition, considering this still little addressed potential, this work summarizes the use of hops in different food matrices and emphasizes the relevant aspects that circumvent it. The development of "hopped products" in addition to their potential use as food preservatives expanded the hop industrial perspectives. Among the non-beer foods, meat products, minimally processed vegetables, bread, and premium products, including non-alcoholic beverages, showed up as great options to hop compound incorporation. Consumer perception based on current trends for hopped products also indicates interesting prospects for industrial spread. [ABSTRACT FROM AUTHOR]

Aiming at the mitigation of the toxicologically relevant styrene formed during wheat beer brewing, different malting parameters, such as steeping temperature, germination temperature, withering and kilning temperatures applied during kiln-drying, and aeration rate, were evaluated for their suitability to reduce the content of cinnamic acid, the precursor of styrene, in malts of barley and wheat, responsible for the input of the undesired precursor into the brewing process. According to the results of the present study, higher steeping temperatures, higher germination temperatures, lower aeration rates, and lower withering temperatures during malting are beneficial for the overall reduction of cinnamic acid in wort produced with barley and wheat malts. Thereby, the withering temperature showed the highest impact among the investigated parameters, able to reduce the soluble cinnamic acid content in wort by up to 72%, followed by the germination temperature in combination with the aeration rate and the steeping temperature with reduction capacities of 52 and 16%, respectively. Additionally, a kilning temperature of 200 °C led to the absence of enzyme activities in dark malts, which might also be the main reason for the low phenolic acid contents found in the corresponding wort, finally causing the low concentrations of styrene but also to a certain extent of desired vinyl aromatics in dark wheat beers. [ABSTRACT FROM AUTHOR]

Hop (Humulus lupulus L.): Traditional and Present Use, and Future Potential. Hop (Humulus lupulus) is best known for its use in beer brewing owing to its bittering flavor and floral aroma. Today, the brewing industry uses as much as 98% of the produced hop crop worldwide. However, there are many other uses, some of them known since prehistoric times. Hops, the cone–like female structures called strobili, are the most frequently used part of the hop plant, but other tissues are of interest as well. The present review compiles existing knowledge of the chemical and pharmacological properties, traditional and present uses and further use potential, genetic resources, and breeding attempts in H. lupulus, and discusses climate change challenges to hop production. It contains hundreds of phytochemicals, and some of the secondary metabolites have definite potential pharmacological and medicinal value, but further investigations are desirable. Hop substances are potential alternatives, e.g., in antimicrobial, cancer, metabolic syndrome, and hormone replacement therapy treatments, as well as insecticides, preservatives, and fragrances. There are presently a few hundred cultivated hop varieties, and new cultivars are being developed and tested. Future hop breeding efforts with different quality and adaptation targets can utilize existing genetic resources, such as wild populations and landraces present in many regions. [ABSTRACT FROM AUTHOR]

Ethyl-acetate is important for the flavor and aroma of the alcoholic beverages, therefore, there have been extensive efforts toward increasing its production by engineering yeast strains. In this study, we reported a new approach to breed non-genetic modified producing yeast strain with higher ethyl-acetate production for beer brewing. First, we demonstrated the positive effect of higher acetic acid concentration on inducing the expression of acetyl-CoA synthetase (ACS). Then, we applied adaptive laboratory evolution method to evolve strain with higher expression level of ACS. As a result, we obtained several evolved strains with increased ACS expression level as well as ethyl-acetate production. In 3 L scale fermentation, the optimal strain EA60 synthesized more ethyl-acetate than M14 at the same time point. At the end of fermentation, the ethyl-acetate production in EA60 was 21.4% higher than M14, while the other flavor components except for acetic acid were changed in a moderate degree, indicating this strain had a bright prospect in industrial application. Moreover, this study also indicated that ACS1 played a more important role in increasing the acetic acid tolerance of yeast, while ACS2 contributed to the synthesis of cytosol acetyl-CoA, thereby facilitating the production of ethyl-acetate during fermentation. [ABSTRACT FROM AUTHOR]

The use of non-conventional yeast species to obtain interesting flavors and aromas has become a new trend in the fermented beverages industry. Among such species, Brettanomyces bruxellensis (B. bruxellensis) has been reported as capable of producing desirable or at least singular aromas in fermented beverages like beer and wine. However, this yeast can also produce an aromatic defect by producing high concentrations of phenolic compounds like, 4-ethylguaiacol and particularly 4-ethylphenol (4-EP). In the present study, we designed a mutant screening method to isolate B. bruxellensis mutants with reduced 4-EP production. More than 1000 mutants were screened with our olfactory screening method, and after further sensory and chemical analysis we were able to select a B. bruxellensis mutant strain with a significant reduction of 4-EP production (more than threefold) and less phenolic perception. Notably, the selected strain also showed higher diversity and concentration of ethyl esters, the most important group of odor active compounds produced by yeasts. Based on these results, we consider that our selected mutant strain is a good candidate to be tested as a non-conventional yeast starter (pure or in co-inoculation) to obtain wines and beers with novel aromatic properties. [ABSTRACT FROM AUTHOR]

Saccharomyces paradoxus is commonly isolated from environmental samples in Northern Europe and North America, but is rarely found associated with fermentation. However, as novelty has become a selling point in beer markets, interest toward non-conventional and local yeasts is increasing. Here, we report the first comprehensive investigation of the brewing potential of the species. Eight wild strains of S. paradoxus were isolated from oak trees growing naturally in Finland, screened in a series of fermentation trials and the most promising strain was selected for lager beer brewing at pilot scale (40 l). Yeasts were evaluated according to their ability to utilize wort sugars, their production of flavour-active aroma volatiles, diacetyl and organic acids, and sensorial quality of beers produced. All strains could assimilate maltose but this occurred after a considerable lag phase. Once adapted, most wild strains reached attenuation rates close to 70%. Adaptation to maltose could be maintained by re-pitching and with appropriate handling of the adapted yeast. Fermentation at 15 °C with the best performing strain was completed in 17 days. Maltose was consumed as efficiently as with a reference lager yeast, but no maltotriose use was observed. Bottled beers were evaluated by a trained sensory panel, and were generally rated as good as, or better than, reference beers. S. paradoxus beers were considered full-bodied and had a relatively clean flavour profile despite the presence of the clove-like 4-vinyl guaiacol. In conclusion, S. paradoxus exhibits a number of traits relevant to brewing, and with appropriate handling could be applied industrially. [ABSTRACT FROM AUTHOR]

In the yeast Saccharomyces cerevisiae, the mitochondrial branched-chain amino acid (BCAA) aminotransferase Bat1 plays an important role in the synthesis of BCAAs (valine, leucine, and isoleucine). Our upcoming study (Large et al. bioRχiv. 10.1101/2020.06.26.166157, Large et al. 2020) will show that the heterozygous tetraploid beer yeast strain, Wyeast 1056, which natively has a variant causing one amino acid substitution of Ala234Asp in Bat1 on one of the four chromosomes, produced higher levels of BCAA-derived fusel alcohols in the brewer's wort medium than a derived strain lacking this mutation. Here, we investigated the physiological role of the A234D variant Bat1 in S. cerevisiae. Both bat1∆ and bat1A234D cells exhibited the same phenotypes relative to the wild-type Bat1 strain—namely, a repressive growth rate in the logarithmic phase; decreases in intracellular valine and leucine content in the logarithmic and stationary growth phases, respectively; an increase in fusel alcohol content in culture medium; and a decrease in the carbon dioxide productivity. These results indicate that amino acid change from Ala to Asp at position 234 led to a functional impairment of Bat1, although homology modeling suggests that Asp234 in the variant Bat1 did not inhibit enzymatic activity directly. Key points: • Yeast cells expressing Bat1A234Dexhibited a slower growth phenotype. • The Val and Leu levels were decreased in yeast cells expressing Bat1A234D. • The A234D substitution causes a loss-of-function in Bat1. • The A234D substitution in Bat1 increased fusel alcohol production in yeast cells. [ABSTRACT FROM AUTHOR]

Sorghum has been used for brewing European beers but its malt generally lower beer yields and alcohol contents. The aim of this research was to produce lager beers using worts from sorghum malted with and without Aspergillus oryzae inoculation. Worts adjusted to 15° Plato from the sorghum malt inoculated with 1% A. oryzae yielded 21.5% and 5% more volume compared to sorghum malt and barley malt worts, respectively. The main fermentable carbohydrate in all worts was maltose. Glucose was present in higher amounts in both sorghum worts compared to barley malt worts. Sorghum–A. oryzae beer had similar specific gravity and alcohol compared to the barley malt beer. Sorghum–A. oryzae beer contained lower amounts of hydrogen sulfide, methanethiol, butanedione, and pentanedione compared to barley malt beer. Sorghum–A. oryzae lager beer had similar yield and alcohol content compared to the barley malt beer but differed in color, key volatiles and aromatic compounds. [ABSTRACT FROM AUTHOR]

Key message: Seven novel alleles of SBEIIb and one allele of SSIIa co-segregated with the ASV phenotype and contributed to distinct starch quality traits important for food-processing applications. Sorghum is an important food crop for millions of people in Africa and Asia. Whole-genome re-sequencing of sorghum EMS mutants exhibiting an alkali spreading value (ASV) phenotype revealed candidate SNPs in Sobic.004G163700 and Sobic.010G093400. Comparative genomics identified Sobic.010G093400 as a starch synthase IIa and Sobic.004G163700 as a starch branching enzyme IIb. Segregation analyses showed that mutations in Sobic.010G093400 or Sobic.004G163700 co-segregated with the ASV phenotype. Mutants in SSIIa exhibited no change in amylose content but expressed lower final viscosity and lower starch gelatinization temperature (GT) than starches from non-mutant plants. The sbeIIb mutants exhibited significantly higher amylose levels and starch GT and lower viscosity compared to non-mutant starches and ssIIa mutants. Mutations in SBEIIb had a dosage-dependent effect on amylose content. Double mutants of sbeIIb and ssIIa resembled their sbeIIb parent in amylose content, starch thermal properties and viscosity profiles. These variants will provide opportunities to produce sorghum varieties with modified starch end-use qualities important for the beer brewing and baking industries and specialty foods for humans with diabetes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The purpose of lautering in beer brewing is to separate the wort, which contains soluble malt components from the solids, the brewer's spent grains. Lautering is a critical point in wort production and its primary objective is the efficient recovery of extract. Lautering is a special type of cake filtration; the particle sedimentation behavior of the mash results in an inhomogeneous filter cake whose structure has an impact on its chemical composition. Components of interest within the filter cake are polysaccharides, such as starch byproducts, β-glucan, and arabinoxylan, as well as proteins, lipids, polyphenols, and metal ions. The distribution of these components within the inhomogeneous filter cake is presented in this review. Lautering is a combination of separation and extraction. During extraction, the solubility of each filter cake component is different. Therefore, in this paper, lautering is considered from a new angle—a chromatographic viewpoint. The initial concentration of the components in malt is compared to their degree of retention in the filter cake and extraction into the wort. Differences in the analyses of brewer's spent grains due to different sampling points within the filter cake are addressed in this review. This new information is important for the use of spent grains in biotechnological processes and enables a more accurate comparison of components from different brewer's spent grain analyses. [ABSTRACT FROM AUTHOR]

Acetaldehyde is synthesized by yeast during the main fermentation period of beer production, which causes an unpleasant off-flavor. Therefore, there has been extensive effort toward reducing acetaldehyde to obtain a beer product with better flavor and anti-staling ability. In this study, we discovered that acetaldehyde production in beer brewing is closely related with the intracellular NADH equivalent regulated by the citric acid cycle. However, there was no significant relationship between acetaldehyde production and amino acid metabolism. A reverse engineering strategy to increase the intracellular NADH/NAD+ ratio reduced the final acetaldehyde production level, and vice versa. This work offers new insight into acetaldehyde metabolism and further provides efficient strategies for reducing acetaldehyde production by the regulating the intracellular NADH/NAD+ ratio through cofactor engineering. [ABSTRACT FROM AUTHOR]

Incompletely degraded corn starch particles often seriously inhibit wort filtration and decrease a brewery's beer productivity. Herein, the inhibiting factors of starch hydrolysis and the application of amylases to degrade residual starch were evaluated. The results showed that resistant starch and the amylopectin of corn starch were not the inhibiting factors. Almost all residual starch left in the spent grain layer was proved to be degradable by amylases. Mesophilic α-amylase was selected through a comparison of nine amylases, which increased the wort filtration rate by 44%. However, >6% of corn starch was still left after mashing when a high ratio of corn starch to water (>1:3.5) was used in liquefaction. The low water content in liquefaction was proved to be the key inhibiting factor. Considering the existing equipment and brewing technology, the application of mesophilic α-amylases should be a simple and effective method for enhancing the hydrolysis of corn starch and accelerating the wort lautering process during a high-adjunct-ratio beer brewing process. [ABSTRACT FROM AUTHOR]

The beer-brewing process produces high amounts of nutrient-rich wastewater, and the increasing number of microbreweries worldwide has created a need for innovative solutions to deal with this waste. In the present study, fungal biomass production and the removal of organic carbon, phosphorus and nitrogen from synthetic brewery wastewater were studied. Different filamentous fungi with a record of safe use were screened for growth, and Trametes versicolor, Pleurotus ostreatus and Trichoderma harzianum were selected for further work. The highest biomass production, 1.78 ± 0.31 g L of dry weight, was observed when P. ostreatus was used for the treatment, while T. harzianum demonstrated the best capability for removing nutrients. The maximum reduction of chemical oxygen demand, 89% of the initial value, was observed with this species. In the removal of total nitrogen and phosphorus, no significant difference was observed between the species, while removal of ammonium varied between the strains. The maximum reduction of ammonium, 66.1% of the initial value, was also found in the T. harzianum treatment. It can be concluded that all treatments provided significant reductions in all water-quality parameters after 3 days of growth and that the utilisation of filamentous fungi to treat brewery wastewater, linked to a deliberate strategy to use the biomass produced, has future potential in a bio-based society. [ABSTRACT FROM AUTHOR]

The natural interspecies Saccharomyces cerevisiae × Saccharomyces eubayanus hybrid yeast is responsible for global lager beer production and is one of the most important industrial microorganisms. Its success in the lager brewing environment is due to a combination of traits not commonly found in pure yeast species, principally low-temperature tolerance, and maltotriose utilization. Parental transgression is typical of hybrid organisms and has been exploited previously for, e.g., the production of wine yeast with beneficial properties. The parental strain S. eubayanus has only been discovered recently and newly created lager yeast strains have not yet been applied industrially. A number of reports attest to the feasibility of this approach and artificially created hybrids are likely to have a significant impact on the future of lager brewing. De novo S. cerevisiae × S. eubayanus hybrids outperform their parent strains in a number of respects, including, but not restricted to, fermentation rate, sugar utilization, stress tolerance, and aroma formation. Hybrid genome function and stability, as well as different techniques for generating hybrids and their relative merits are discussed. Hybridization not only offers the possibility of generating novel non-GM brewing yeast strains with unique properties, but is expected to aid in unraveling the complex evolutionary history of industrial lager yeast. [ABSTRACT FROM AUTHOR]

Objectives: To study enhanced barley germination by chitooligosaccharide as an elicitor for improving the quality of malt. Results: Barley germination for both radical and leaf sprouts was enhanced when chitooligosaccharide was added to the steeping water in the first steeping cycle. The activities of hydrolases (α-/β-amylase, proteinase and β-glucanase) and antioxidases (superoxide dismutase and catalase) in the resultant malt were increased in a dose-dependent manner when chitooligosaccharide was supplemented in the steeping water. Maximal promotion was at 1 mg chitooligosaccharide/l for α-/β-amylase and proteinase, and at 10 mg/l for β-glucanase, superoxide dismutase and catalase. Malt quality, including free α-amino nitrogen content, Kolbach index, malt extract content, diastatic power, wort viscosity and the ratio of glucose, maltose and maltotriose, was significantly improved by chitooligosaccharide in seed priming at 1 mg/l. Conclusion: Application of chitooligosaccharide in the steeping water promotes barley germination and improves the quality of malt. [ABSTRACT FROM AUTHOR]

Objectives: To identify a biological preservative that can protect beer from microbial contamination, which often results in the production of turbidity and off-flavor. Results: The antimicrobial activity of a chitooligosaccharide against beer-spoilage bacteria and its effect on the fermentation performance of brewer's yeast was studied. Chitooligosaccharide with an average 2 kDa molecular weight was the best at inhibiting all tested beer-spoilage bacteria. The application of chitooligosaccharide in the brewing process did not influence the fermentation of brewer's yeast. The change in beer performance induced by the contamination of Lactobacillus brevis could be effectively controlled by application of chitooligosaccharide in the beer brewing process. Conclusion: The experimental data suggested that chitooligosaccharide should be an excellent preservative to inhibit beer-spoilage bacteria in the brewing process and in the end product. [ABSTRACT FROM AUTHOR]

The effect of a-acetolactate decarboxylase (ALDC) on the diacetyl content of beer was studied. Diacetyl is known as an off-flavor compound in beer due to its buttery flavor. ALDC is known to reduce diacetyl by bypassing the diacetyl formation pathway. Herein, beer was brewed with two-row barley (Jinyang) and six-row barley (Dahyang) cultured in Korea with the addition of ALDC. The formation of diacetyl is reversely affected by free amino nitrogen, such as valine. ALDC (0.02, 0.04, and 0.06 unit/mL) was added to the samples, and the physicochemical properties of the resulting beer were analyzed to determine the quality. Diacetyl content was decreased in proportion to the enzyme concentration. The diacetyl content in samples made from Jinyang and Dahyang decreased by 25 and 15%, respectively. The diacetyl content in both was acceptable for microbrewery. [ABSTRACT FROM AUTHOR]

"While the found content of 6.2 g/L niacin in the historical beer is plausible for a lager beer of the time (compare 10.3 g/L in a strong beer of 1872 SP 34 sp ), no niacin signal above the detection limit could be found in modern equivalent (Fig. Its low content in nowadays beers (5 mg/L SP 37 sp ) cannot be attributed to higher concentrations in historical barley cultivars with levels being consistent between 80 and 120 µg/g SP 33,34,38,39 sp ." now reads: "While the found content of 6.2 mg/L niacin in the historical beer is plausible for a lager beer of the time (compare approx. 10.3 mg/L in a strong beer of 1872 SP 34 sp ), no niacin signal above the detection limit could be found in modern equivalent (Fig. [Extracted from the article]

The increased additive amount of adjuncts in the raw materials of Chinese beer requires the usage of protease to release more water-soluble proteins. Here, a metallo-neutral protease suited for brewing industry was purified from Bacillus amyloliquefaciens SYB-001. A 5.6-fold purification of the neutral protease was achieved with a 4-step procedure including ammonium sulfate precipitation, ion-exchange, hydrophobic interaction, and gel-filtration chromatography. The molecular mass of the enzyme was estimated to be 36.8 kDa. The protease was active and stable at a wide range of pH from 6.0-10.0 with an optimum at pH 7.0. The highest activity of the purified enzyme was found at 50 °C. The existence of manganese ion would specifically enhance the protease activity. Comparing with other commercial neutral proteases in China, adding the new neutral protease during mashing process would release more amino acids from wort such as aspartic acid, arginine, methione, and histidine, resulting in a better amino acid profile in wort. Moreover, the wort processed with the new neutral protease had a higher α-amino nitrogen concentration, which would ensure a vigorous yeast growth and better flavor. The study of the enzyme could lay a foundation for its industrial application and further research. [ABSTRACT FROM AUTHOR]

A widely cultivated cocoyam variety, Xanthosoma sagittifollium, was assessed for its suitability for lager beer production, using malted Sorghum vulgare (white variety) for saccharification of the substrate. The three-mash decoction method was used. Results showed that the cocoyam was superior to barley and sorghum as a substrate because of its potentially higher carbohydrate content (71-78%) compared to barley (65%) and sorghum (70-73%). The percentage wort extract was 13.3-14.5 degrees plato compared to 7-12 for barley and 13 degrees for the tuber crop, cassava. The kiln dried Xanthosoma sagittifollium gave a dark bager beer with good aroma (68%) and very good flavour (73%) when compared with a commercial lager beer (Monarch) as standard (100%). The alcohol content (4.16% w/v) and the specific gravity (1013) were within the range (4.0-6.4%) and (1011-1019), respectively, specified by the Standard Organization of Nigeria. Although the bitterness value 40 EBU, was higher than the typical range 16-30 EBU, the taste panel indicated this was acceptable. The pH was 4.68 compared with the standard 4.36, while the acidity (as % lactic acid) was 0.36 compared to 0.24 for some commercial products. [ABSTRACT FROM AUTHOR]

The characteristics of yeast carbohydrate metabolism in a multistage bioreactor system for rapid beer fermentation were investigated. The yield of biomass in a continuous stirred-tank reactor (CSTR) was approx 10%, whereas the yield in an immobilized yeast packed-bed reactor (PBR) was below 1.0%. The overall ethanol productivity per extract consumed was slightly higher than for conventional beer fermentation owing to the restricted growth of immobilized yeast. The organic acid composition was different from a conventional fermentation broth, i.e., higher amount of succinate and lower amount of acetate. Virtually no acetate was produced in the CSTR. Succinate was produced in both the CSTR and PBR, but the amount produced per extract consumed was approximately two times larger in the CSTR. A large amount of a-acetolactate was produced in an early stage of a continuous operation of the PBR. However, once the immobilized yeast growth had stabilized, the productivity was lowered to approx 0.07 mg/(10 mg extract). Control of the amino acid composition of the wort fed to the PBR was not effective in repressing the production of α-acetolactate in the PBR. A strategy for controlling minor byproducts of carbohydrate metabolism in a multistage beer fermentation system was discussed. [ABSTRACT FROM AUTHOR]

Main aim of our project was to set up a complex innovation system which gives a chance to produce high value special organic beer made of einkorn. Therefore all the stakeholders of the production chain from breeding till the end user brewery were involved in the innovation. This kind of research resulted in a marketable high value organic beer product. It belongs to the recently favourable beverage fashion of healthy foods in a premium category market niche. The field technology for successful einkorn production and growing seed production was developed thanks to this project. As no long cultivation knowledge was in the background, several technological steps were still open. To be able to set up economically seed production technology, half-farm and farm scale experiments were carried out to optimize several important factors, such as plant density, fertilizer needs, optimal harvest time, etc. The technology improvement was run together with the development of seed production system under diverse ecological conditions. Our new R & D & I work in Elixbeer project is aimed at creating an organic beer brand based on Hungarian Cereal varieties, aiming at the development of special organic beers and malted drinks and organic malt. Several type of organic cultivation of malting barley, triticale, wheat and rye will be tested on farm level at Körös Maros Biofarm Ltd. under supervision of GK Ltd. and MTA ATK and a new organic cultivation technology will be developed. The preceding Alkobeer project focused on organic bred einkorn wheat and on the organic einkorn beer made from it. The compliance of organic ingredients and the brewing process is certified over a batch certificate. The batch certification process covers the whole value chain starting from the breeding of modern einkorn varieties, across the recipe and technology development, the production and purchasing of row materials, the brewing and the trading process. The einkorn beer is certified organic, from the field to the bottle. Researchers of MTA ATK focused their activity mainly on organic einkorn breeding in ALKOBEER project. MTA ATK produced several new crossing combinations using einkorn lines, to produce new einkorn varieties for brewing. The results of their activity are two new einkorn genotypes. One of them, Mv Menket was registered in 2011. Mv Menket is a semi-dwarf einkorn variety with outstanding lodging resistance, recommended for intensive organic farming. The new line, MvA6-13, is a traditional type of einkorn. It was applied for variety registration in 2013. MvA6-13 is a high yielding quality with low protein content. Methods of maintenance breeding and organic seed production of einkorn were developed by MTA-ATK. Cereal Research Ltd. has also strong crop plant breeding programmes, producing a wide range of varieties, two row, six row, feed, malting barley, triticale and wheat which are successfully marketed across Eastern Europe. Our spring type malting barley varieties GK Habzó and GK Toma are potentially promising raw materials for craft beer brewing. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the Ancient Egyptians used malted wheat and barley as the main ingredients in beer brewing, but the chemical determination of the exact recipe is still lacking. To investigate the constituents of ancient beer, we conducted a detailed IR and GC-MS based metabolite analyses targeting volatile and non-volatile metabolites on the residues recovered from the interior of vats in what is currently the world's oldest (c. 3600 BCE) installation for large-scale beer production located at the major pre-pharaonic political center at Hierakonpolis, Egypt. In addition to distinguishing the chemical signatures of various flavoring agents, such as dates, a significant result of our analysis is the finding, for the first time, of phosphoric acid in high level probably used as a preservative much like in modern beverages. This suggests that the early brewers had acquired the knowledge needed to efficiently produce and preserve large quantities of beer. This study provides the most detailed chemical profile of an ancient beer using modern spectrometric techniques and providing evidence for the likely starting materials used in beer brewing. [ABSTRACT FROM AUTHOR]