Search Results (365)

The role of science and technology in enhancing beer quality is crucial amid growing market demands. This pilot study assessed the clarity and physicochemical stability of laboratory beers treated post fermentation with three clarifying (fining) agents: two chitosan-based and one collagen-based (fish bladder/isinglass). The beers were brewed with Polish barley malt and hops (alpha acids 7.5% and 14.5%). The measured parameters included pH, colour, turbidity, viscosity, surface tension, and foam volume. Within this small-scale, low-power dataset, both the collagen- and chitosan-based agents improved clarity, with the collagen agent showing the lowest turbidity in this sample. The clarifying agents also influenced the colour and surface tension, while the pH was largely unchanged. The foam volume increased with fining. Shelf-life checks suggested improved stability in clarified beers, with no clear differences between agents under these conditions. These findings are preliminary. The results should be interpreted cautiously due to the limited number of replicates. Larger scale studies with adequate replication are required before translating these observations into brewing practice. Chitosan's effectiveness as a clarifying agent aligns with its high charge density and ability to coagulate suspended particles. This study underscores the importance of selecting appropriate clarifying agents to optimize beer clarity and stability while maintaining essential physicochemical properties. These findings contribute to the brewing industry's efforts to meet consumer expectations for high-quality, stable beer products. Full article

Considering the importance of free amino acids (FAAs) and biogenic amines (BAs) in the production of fermented beverages (FB), the interest in the quantification of these compounds has been growing. So far, most of the analytical methods developed entail a derivatization step. While this technique allows for the detection of several compounds, it is often associated with scarce accuracy and poor resolution. To counteract the drawbacks, in this study, we aimed to develop a fast, simple, and effective method that combines the use of ultra-high-performance liquid chromatography (UHPLC) and high-resolution mass spectrometry (HRMS) to quantify underivatized FAAs and BAs in FBs. The method was successfully developed and validated: it allowed for the accurate and precise quantification of 20 FAAs—including leucine and isoleucine—and 12 BAs in just 12 min. Its applicability was demonstrated on commercial samples of wines, beers, ciders, saké, and vinegars. Full article

Potentially probiotic yeasts isolated from foodstuffs can be used as components in functional fermented beverages. To date, there have been no reports on the use of Saccharomyces cerevisiae var. boulardii, Pichia kudriavzevii, Metschnikowia pulcherrima, or Hanseniaspora uvarum isolates in the production of a traditional Polish beverage called underbeer (podpiwek). The aim of the study was to determine the usefulness of six isolates of the above-mentioned species as starter cultures for the fermentation of underbeer. First, the important characteristics of the yeasts, like ethanol tolerance and H₂S production, were examined. In the next stage, the wort was fermented by the tested yeasts, and cell viability, fermentation vigor, sugar assimilation, and production of metabolites, as well as properties of the beverage (pH, titratable acidity, color, and turbidity), were determined. Saccharomyces yeasts tolerated the addition of ethanol up to 16% (v/v), while Pichia, Metschnikowia, and Hanseniaspora tolerated up to 10% (v/v) ethanol, and all except H. uvarum produced H₂S. The yeasts remained viable in the beverages for 1 month at the required level, utilized glucose, fructose and partially complex carbohydrates, and produced ethanol (S. cerevisiae, P. kudriavzevii, and M. pulcherrima) and organic acids such as tartaric, malic, and citric acid. The underbeers became sour and showed varying turbidity and a color corresponding to pale-amber beers. All tested strains produced fermented beverages that were low- or non-alcoholic with different properties. This experiment may be a starting point for research into regional products as probiotic or synbiotic foods; however, further research is required for selection of the best strains for underbeer fermentation. Full article

Although vinegar is technically elaborated by a well-known bioprocess, the behavior and function of the microorganisms responsible for its production still need investigation. In vinegars obtained from raw materials and systems typical of Europe, the acetic acid bacteria species Komagataeibacter europaeus predominates due to its particular adaptive metabolism. This work addresses the study of several adaptation mechanisms of K. europaeus during acetic acid fermentation in a submerged semi-continuous production system. The aim is to analyze the molecular response and behavior of this species to increasing acidity gradients, up to 7–8% w/v acetic acid, applying a comparative proteomic approach in three matrices (synthetic alcoholic medium, dark craft beer, and dry fine wine). A total of 1070 proteins are identified, with 174 showing statistically significant changes in abundance (FDR < 0.05), particularly in pathways related to amino acid biosynthesis, fatty acid metabolism, and stress response. The proteomic patterns differ among substrates, with the synthetic alcohol medium inducing stress-related proteins and the dark craft beer enhancing lipid biosynthesis. These observations provide experimental evidence that the fermentation substrate modulates metabolic adaptation in K. europaeus, offering a rational basis for designing fermentation protocols that enhance bacterial resilience, thereby optimizing vinegar production processes. Full article

Fruit and sour beers are popular due to their unique sensory characteristics. Owing to changes in physicochemical parameters, mixed culture fermentation is a promising research area. The aim of the study was to evaluate how ethanol and lactic acid fermentation, combined with the addition of berry fruits during the beer production process, influence the physicochemical and sensory characteristics of sour fruit beers. Three worts differing in hopping system were produced: one classic sweet wort and two lacto-fermented. Strawberries or raspberries were added to the young beer. This research showed that acidification of wort, fruit addition, and limiting of hopping time had a positive effect on both technological and sensory characteristics. Despite pH differences, alcohol content in beers was similar (2.52–3.21% v/v). Production method influenced mainly lactic acid (0–2.30 g/L), pH (3.53–4.79), and glycerol (0.83–1.62 g/L) contents. Non-acidified beers had the highest dextrin (17.64–23.13 g/L) and glycerol (1.36–1.62 g/L) levels. The addition of strawberries increased phenolics (205.21–237.03 mg GAE/L), FRAP (0.82–1.17 mmol TE/L), and refreshment sensation, while raspberries mainly enhanced sensory atributes (colour, foam, fruitiness, aroma). Lactic fermentation did not show a clear effect on polyphenol content or antioxidant activity. The research offers practical insights into functional beer development, with its novelty of using mixed fermentation and fruit addition to shape characteristics. Full article

Although beer fermentation has traditionally been carried out with Saccharomyces, the boom in craft brewing has led to the use of non-conventional yeast species for beer production. This group also includes non-Saccharomyces starters, which are commonly used in winemaking and which have different technological characteristics compared to standard representatives of the Saccharomyces genus. One of the important characteristics of the non-Saccharomyces group is the richer enzyme profile, which leads to the production of beverages with different taste and aroma profiles. The aim of this study was to investigate sweet and hopped wort fermentation with seven strains of active dry non-conventional yeasts of Lachancea spp., Metschnikowia spp., Torulaspora spp. and a mixed culture of Saccharomyces cerevisiae and Torulaspora delbrueckii. One ale and one lager active dry yeast strain were used as control strains. The extract consumption, ethanol production, degree of fermentation, pH drop, as well as the yeast secondary metabolites formed by the yeast (higher alcohols, esters and aldehydes) in sweet and hopped wort were investigated. The results indicated that all of the studied types of non-conventional yeasts have serious potential for use in beer production in order to obtain new beer styles. For the purposes of this study, statistical methods, principle component analysis (PCA) and correlation analysis were used, thus establishing the difference in the fermentation kinetics of the growth in the studied species in sweet and hopped wort. It was found that hopping had a significant influence on the fermentation kinetics of some of the species, which was probably due to the inhibitory effect of the iso-alpha-acids of hops. Directions for future research with the studied yeast species in beer production are presented. Full article

The incorporation of Cannabis sativa L. seeds into barley wort was investigated to enhance the functional profile of beer. Hemp seeds (cv. Henola) were malted via controlled steeping, germination, and kilning, then added to barley malt at 10% and 30% (w/w) in both malted and unmalted forms. Standard congress mashing produced worts whose physicochemical parameters (pH, extract, colour, turbidity, filtration and saccharification times) were assessed, alongside profiles of fermentable sugars, polyphenols, B-group vitamins, and cannabinoids. Addition of hemp seeds reduced extract yield without impairing saccharification or filtration and slightly elevated mash pH and turbidity. Maltose and glucose levels declined significantly at higher hemp dosages, whereas sucrose remained stable. Wort enriched with 30% unmalted seeds exhibited the highest levels of trans-ferulic (20.61 µg/g), gallic (5.66 µg/g), trans-p-coumaric (3.68 µg/g), quercetin (6.07 µg/g), and trans-cinnamic (4.07 µg/g) acids. Malted hemp addition enhanced thiamine (up to 0.302 mg/mL) and riboflavin (up to 178.8 µg/mL) concentrations. Cannabinoids (THCA-A, THCV, CBDV, CBG, CBN) were successfully extracted at µg/mL levels, with the total cannabinoid content peaking at 14.59 µg/mL in the 30% malted treatment. These findings demonstrate that hemp seeds, particularly in malted form, can enrich barley wort with bioactive polyphenols, vitamins, and non-psychoactive cannabinoids under standard mashing conditions, without compromising key brewing performance metrics. Further work on fermentation, sensory evaluation, stability, and bioavailability is warranted to realise hemp-enriched functional beers. Full article

In the forest ecosystems of Central European Russia, the influence of forest edges on the spatial distribution of Drosophilidae was studied for the first time. The research was conducted during the period of 2021–2022 in the Republic of Mordovia. Beer traps baited with fermented beer and sugar were used to collect Drosophilidae. Two study plots were selected, differing in their forest edges, tree stands, and adjacent open ecosystems. In both cases, the forest directly bordered an open ecosystem. Edges serve as transitional biotopes, where both forest and meadow (open area) faunas coexist. Knowing that many drosophilid species prefer forest habitats, we designated forest interior sites as control points. Traps were set at heights of 1.5 m (lower) and 7.5 m (upper) on trees. A total of 936 specimens representing 27 species were collected. Nine species were common across all traps, while ten species were recorded only once. At the forest edges, 23 species were captured across both heights, compared to 19 species in the forest interiors. However, the total abundance at the forest edges was 370 specimens, while it was 1.5 times higher in the forest interiors. Both abundance and species richness varied between plots. Margalef’s index was higher at the forest edges than in the forest interiors, particularly at 1.5 m height at the edge and at 7.5 m height in the forest interior. Shannon and Simpson indices showed minimal variation across traps at different horizontal and vertical positions. The highest species diversity was observed among xylosaprobionts (9 species) and mycetophages (8 species). All ecological groups were represented at the forest edges, whereas only four groups were recorded in the forest interiors, with the phytosaprophagous species Scaptomyza pallida being absent. In general, both species richness and drosophilid abundance increased in the lower strata, both at the forest edge and within the interior. Using the R package Indicspecies, we identified Gitona distigma as an indicator species for the forest edge and Scaptodrosophila rufifrons as an indicator for the forest interior in the lower tier for both plots. In addition, Drosophila testacea, D. phalerata, and Phortica semivirgo were found to be indicator species for the lower tier in both plots, while Leucophenga quinquemaculata was identified as an indicator species for the upper tier at the second plot. Full article

Solid-state fermentation (SSF) involves the growth of microorganisms on solid substrates, mimicking natural environments of many species. Due to sustainability concerns, transforming agro-industrial by-products into value-added products through SSF has been increasingly studied. Brewer’s spent grain (BSG), the main by-product of beer production, mostly consists of barley grain husks, making BSG a great support for microorganism cultivation. Although autoclaving remains the standard sterilization and pretreatment method of substrates, electric field technologies and their attendant ohmic heating (OH) have great potential as an alternative technology. In the present work, pretreatment of BSG by OH was explored in SSF with Aspergillus niger to produce commercially valuable enzymes. OH favored the solubilization of phenolic compounds, total protein, and reducing sugars significantly higher than autoclaving. SSF of treated BSG led to the production of lignocellulosic enzymes, with xylanases being the most active, reaching 540 U/g, a 1.5-fold increase in activity compared to autoclaved BSG. Protease activity was also improved 1.6-fold by OH, resulting in 49 U/g. Our findings suggest that OH treatment is an effective alternative to autoclaving and that its integration with SSF is a sustainable strategy to enhance by-product valorization through enzyme production with many industrial applications, according to circular economy guidelines. Full article

Wild ales represent a diverse category of spontaneously fermented beers, influenced by complex microbial populations and variable ingredients. This study employed an integrated metabolomic profiling approach combining proton nuclear magnetic resonance (¹H NMR) spectroscopy, liquid chromatography–mass spectrometry (LC-MS), and spectrophotometric assays (DPPH and FRAP) to characterize the molecular composition and antioxidant potential of 22 wild ales from six countries. A total of 53 compounds were identified and quantified using NMR, while 62 compounds were identified by using LC-MS. The compounds in question included organic acids, amino acids, sugars, alcohols, bitter acids, phenolic compounds, and others. Ingredient-based clustering revealed that the addition of dark fruits resulted in a significant increase in the polyphenolic content and antioxidant activity. Concurrently, herb-infused and light-fruit beers exhibited divergent phytochemical profiles. Prolonged aging (>18 months) has been demonstrated to be associated with increased levels of certain amino acids, fermentation-derived aldehydes, and phenolic degradation products. However, the influence of maturation duration on the antioxidant capacity was found to be less significant than that of the type of fruit. Country-specific metabolite trends were revealed, indicating the influence of regional brewing practices on beer composition. Correlation analysis was employed to identify the major contributors to antioxidant activity, with salicylic, dihydroxybenzoic, and 4-hydroxybenzoic acids being identified as the most significant. These findings underscore the biochemical intricacy of wild ales and exemplify metabolomics’ capacity to correlate compositional variation with functionality and authenticity in spontaneously fermented beverages. Full article

A rising demand for low-gluten beer fuels research into enzymatic solutions. This study optimized Aspergillus niger prolyl endopeptidase (AN-PEP) application timing during brewing to reduce gluten while preserving physicochemical quality. Ale-type beers were produced with AN-PEP (2% v/v) added at mashing, boiling, post-boiling, or post-fermentation, plus a control. Three mashing profiles (Mash A, B, C) were also tested. Gluten was quantified by R5 ELISA (LOQ > 270 mg/L). Color, bitterness, ABV, and foam stability were assessed. Statistical analysis involved ANOVA and Tukey’s HSD (p < 0.05). Enzyme activity and thermal inactivation were also evaluated. Initial gluten levels consistently exceeded LOQ. Significant gluten reduction occurred only post-fermentation. Mashing, boiling, and post-boiling additions effectively lowered gluten to below 20 mg/L. Post-fermentation addition resulted in significantly higher residual gluten (136.5 mg/L). Different mashing profiles (A, B, C) with early enzyme addition achieved similar low-gluten levels. AN-PEP showed optimal activity at 60–65 °C, inactivating rapidly at 100 °C. Physicochemical attributes (color, extract, bitterness, ABV) were largely unaffected. However, foam stability was significantly compromised by mashing and post-fermentation additions, while preserved with boiling and post-boiling additions. AN-PEP effectively produces low-gluten beers. Enzyme addition timing is critical: while mashing, boiling, or post-boiling additions reduce gluten to regulatory levels, only the beginning of boiling or post-boiling additions maintain desirable foam stability. These findings offer practical strategies for optimizing low-gluten beer production. Full article

Beer production produces significant amounts of brewers’ spent grain (BSG), a lignocellulosic by-product with important environmental and economic impacts. Despite its high moisture content and rapid microbial breakdown, BSG has a stable, nutrient-rich composition, especially high in protein, fiber, and polyphenolic compounds. While its perishability limits direct use in food systems, BSG is often repurposed as livestock feed. Recent advances in bioprocessing and extraction technologies have expanded their use across different sectors. This review explores the composition of crude BSG and evaluates innovative valorization methods, including recovering bioactive compounds with pharmaceutical and nutraceutical value, and converting them into biofuels such as biogas, biodiesel, and bioethanol. Special focus is given to methods involving enzymatic hydrolysis, fermentation, and chemical extraction to isolate proteins, peptides, amino acids, sugars, and polyphenols. By analyzing emerging applications and industrial scalability challenges, this review highlights BSG’s growing role within circular economy models and its potential to promote sustainable innovations in both the brewing industry and the wider bioeconomy. Full article

The consumption of low-alcohol fermented beverages has been related to cardiovascular health improvements. Although the underlying mechanism is not completely understood, (poly)phenols have been proposed as one of the mediators. The objective of this study was to evaluate the impact of a controlled intervention with beer on (poly)phenols metabolism in individuals with and without metabolic syndrome (MetS). 20 participants (MetS and control) who consumed a standardized amount of beer during 6 weeks were recruited. Phenolic compounds were assessed in urine. Different changes in phenolic compounds associated with chronic beer consumption were found, particularly related to hesperetin conjugates and to the degradation of phenolic compounds derived from flavonoids and lignans. Noteworthily, MetS and control participants differed in baseline urine phenolic compound profiles and in their metabolization. Significant differences were found in the production and excretion of key (poly)phenols-derived metabolites, such as increased naringenin phase II conjugates in healthy subjects, or increased bacterial flavonoid catabolites. Certain relationships were observed between the phenolic compounds with metabolic and anthropometric variables. These findings suggest that beer-derived (poly)phenols are differentially metabolized according to metabolic-health status, and that they may contribute to certain metabolic health benefits through the modulation of specific metabolic pathways. Full article

Consumer demand for low-alcohol acidic beers is driving the use of non-conventional yeasts in the brewing process. In this study, the addition of mixed berries and fermentation with L. thermotolerans L31 are performed in crafting a low-alcohol acidic beer. Four different beers were brewed in the primary stage with either Saccharomyces cerevisiae or L. thermotolerans and with or without added berry mixture. Beer was fermented for 8 days at 20 °C, stored, and bottled. pH, density, alcoholic content, bitterness, and color of final beer were analyzed for all samples using analytical methods. Volatile compounds, anthocyanin content, and antioxidant activity were also evaluated. Sensory analysis was performed and correlated (PCA) with the analytical results. The obtained data indicated that beers brewed with L. thermotolerans were significantly more acidic and less bitter than S. cerevisiae beers. No difference in alcoholic content was found. Fruity aroma-associated compounds were present in L. thermotolerans beers, which correlated with the sensory analysis. Fruit beers were also redder and showed higher anthocyanin content and stronger antioxidant activity due to the presence of anthocyanins such as cyanidin, delphinidin, and malvidin from fruit, and other antioxidant compounds. Full article

The influence of different Saccharomyces cerevisiae (Sc) strains and hop varieties on the physical, chemical and sensory properties of beer was investigated. ISE77, an oenological Sc strain screened for the IRC7 gene and β-lyase activity, and a commercial yeast, as a control, were experimented with two hops (dry hopping), Mosaic^® (M) and Hallertau Mittelfrüh (HM). Both hop variety and yeast strain exerted a considerable influence on the organoleptic profile of the beer. Samples with M hops exhibited elevated levels of specific volatile compounds (e.g., limonene and linalool). ISE77 generated higher levels of esters, irrespective of the hop variety employed, imparting fruity and floral characteristics. Moreover, the beers fermented with ISE77 showed herbal and spicy notes. Regardless of the hop variety, samples brewed with the control yeast showed higher honey and caramel note levels. Beers fermented with ISE77 and HM exhibited remarkable similarities to those produced with ISE77 and M, particularly for some odour attributes (citrus, exotic fruits, and aromatic herbs). These attributes were more intense than in beers fermented with the control yeast and HM. This study demonstrated the potential of oenological Sc strains to achieve innovative brewing outcomes when combined with selected hops. Full article