Search Results (166)

Yeasts are among the intrinsic factors affecting the quality of beer due to their impact on flavor. Apart from a long and rich brewing tradition of natural fermentations, involving different yeast and bacterial species in regions such as Belgium, non-Saccharomyces yeasts have not been the preferred industrial inoculation strains in both winemaking and brewing sectors. This is mainly due to their slower fermentation rates, lower alcohol tolerance, and limited ability to complete fermentation. This review explores the brewing characteristics of Torulaspora delbrueckii strains, focusing on the aromatic profile of the produced beers, in comparison with the well-known Saccharomyces cerevisiae brewing strains. The effect of fermentation parameters, as well as the use of mono- and mixed cultures with S. cerevisiae, is discussed. Specific T. delbrueckii strains have demonstrated the ability to ferment wort sugars and produce alcohol levels of up to 4–6% (v/v). The main volatile compounds produced include higher alcohols, such as isoamyl and phenyl ethyl alcohol, as well as esters and their acid precursors. Among these, ethyl hexanoate and ethyl octanoate are particularly important due to their contribution to fruity aromas. Mixed fermentations involving T. delbrueckii and S. cerevisiae have been shown to enhance ester production, resulting in improved aromatic complexity in the final product. Full article

Zearalenone (ZEN) is a pervasive mycotoxin contaminating global food and feed. While enzymatic degradation offers a promising, specific, and eco-friendly strategy for mycotoxin mitigation, the biotransformation of ZEN within acidic food matrices remains challenging due to the intrinsically low activity of zearalenone lactonase (ZENG). In this work, we synthesized a ZENG–hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) hybrid nanoflower (CaNF) via biomineralization under alkaline conditions. Compared to free ZENG, the as-prepared biohybrid nanoflower exhibited markedly enhanced acid tolerance and catalytic activity, achieving a 12-fold increase in ZEN degradation efficiency at pH 5.0. Furthermore, the biohybrid nanoflower demonstrated robust performance in various acidic food matrices, including corn juice, wort, beer, and corn steep liquor. This study presents a powerful enzymatic tool for the efficient biotransformation of ZEN in acidic food-related systems. Full article

The diversification of craft beer styles has stimulated interest in innovative yeast-driven strategies to enhance sensory complexity while maintaining process robustness and stylistic integrity. In this context, non-Saccharomyces yeasts represent promising biotechnological tools for modulating fermentation performance and flavor development in brewing systems. This study evaluated the application of Lachancea thermotolerans and Torulaspora delbrueckii in the production of a Porter-style beer using sequential inoculation with Saccharomyces cerevisiae. All fermentations were conducted in triplicate from a wort with an original gravity of 1042. The final alcohol content ranged from 4.82 to 4.99% (v/v), and apparent attenuation varied between 84.1 and 88.9%, with no significant differences among treatments (p > 0.05). Color (92–94 European Brewery Convention (EBC) and bitterness (~18 International Bitterness Units (IBU) remained within Porter-style parameters across all fermentations. Total acidity ranged from 0.19 to 0.21% (lactic acid equivalents), while volatile acidity was significantly higher in the L. thermotolerans treatment (0.55 g L⁻¹) compared with the control (0.22 g L⁻¹) (p < 0.05). Sequential inoculation influenced early fermentation kinetics and modulated selected sensory attributes. Quantitative Descriptive Analysis (n = 18 panelists) indicated higher aroma intensity and foam quantity in beers produced with L. thermotolerans, whereas T. delbrueckii was associated with moderate increases in foam persistence. The roasted character and overall stylistic perception remained stable across treatments. These findings indicate that sequential inoculation with selected non-Saccharomyces yeasts enables measurable sensory differentiation in dark beer matrices without compromising fermentative performance or stylistic integrity. The results support their controlled integration as technological tools for sensory innovation in Porter-style beers. Full article

To address traditional beer detection limitations, this study proposes a rapid NIRS-based method for detecting key indicators and verifying authenticity. Designing Single-task (STL) and Multi-task learning (MTL) strategies, it employs Variable Importance in Projection for wavelength selection. Deep spectral features were extracted utilizing a Multi-Head Attention (MHA)-fused Convolutional Neural Network (CNN-MHA), Long Short-Term Memory (LSTM-MHA), and hybrid CNN-LSTM-MHA networks. To further enhance model performance, the Bayesian Optimization Algorithm globally optimized network hyperparameters in STL, alongside hyperparameters and multi-task loss weights in MTL. Partial least squares regression, support vector machine regression, and partial least squares discriminant analysis models were established using these features. Results indicate that the MTL-based CNN-LSTM-MHA network effectively learns shared features across multiple tasks, significantly improving model generalization. Specifically, the coefficients of determination ($R^2$) for alcohol content and original wort concentration in the validation set were 0.996 and 0.997, respectively, with relative root mean square errors (rRMSE) of 2.024% and 2.515%. In the independent test set, the $R^2$ were 0.995 and 0.991, with rRMSE of 2.515% and 2.087%, respectively. Furthermore, 100% classification accuracy was achieved across all datasets. This method provides an efficient technical solution for beer market regulation and real-time detection in production processes. Full article

Driven by the growing demand for flavor diversification in the global craft beer market, conventional drum roasting for specialty malt faces limitations in time consumption and flavor retention. This study aimed to explore explosive puffing as a novel approach for specialty malt production. Base barley malt was treated via explosive puffing at 0.8 MPa to prepare puffed specialty malt, followed by comprehensive characterization of its physicochemical properties, volatile profile, and antioxidant activity, with brewing trials conducted at 15% grist substitution. Results showed that puffed malt reached a color of 183.15 EBC, with formation of roasted pyrazines and caramel-like furans, and a nearly 3-fold increase in total phenolic content and antioxidant capacity. At 15% addition, the puffed malt maintained wort free amino nitrogen and reducing sugar levels, while significantly enhancing beer color, roasted aroma, and antioxidant activity. These findings demonstrate that explosive puffing is a promising alternative to conventional roasting for producing specialty malt. Full article

The brewing process generates substantial by-products rich in potentially bioactive compounds (e.g., polyphenols and fermentation metabolites), providing a sustainable and appealing source of cosmetic ingredients. Oil-in-water (O/W) emulsions containing 20% (w/w) aqueous extracts from Bionda Triplo Malto beer, wort, and key brewing by-products (hops, yeast, and spent grain) were developed and evaluated using a combined in vitro–in vivo approach. Aqueous extracts were first screened on human immortalized dermal fibroblasts (BJ-5ta) at 0.25–1 mg/mL for cytocompatibility and antioxidant activity. Within this concentration range, no significant changes in cell viability or intracellular antioxidant capacity under UV stress were detected, suggesting cytocompatibility but limited inherent activity. When incorporated into O/W emulsions and tested at an active-equivalent concentration of 10 mg/mL, the formulations increased fibroblast metabolic activity and antioxidant response. In contrast, free extracts at 10 mg/mL showed concentration-dependent cytotoxicity for some matrices, with beer- and yeast-based emulsions demonstrating the strongest effects. The emulsions exhibited good physicochemical stability (pH ~5.7–6.2; viscosity 4750–5150 mPa·s), passed the ISO 11930:2012 challenge test, and were well tolerated in patch testing. In a double-blind, randomized split-forearm study on 50 healthy volunteers over 30 days, beer, yeast, and spent grain-based formulations improved skin parameters versus baseline. TEWL decreased (e.g., beer: 16.22 ± 5.12 to 10.77 ± 2.22 mg·m⁻²·h⁻¹; yeast: 16.29 ± 5.66 to 10.18 ± 1.08; spent grain: 14.45 ± 4.34 to 11.66 ± 2.28), hydration increased (beer: 35.15 ± 5.93 to 42.26 ± 3.78; yeast: 33.27 ± 4.87 to 42.92 ± 2.48; spent grain: 34.22 ± 5.19 to 41.16 ± 3.17, and elasticity improved for beer and yeast formulations (62.33 ± 3.27 to 70.24 ± 2.12 N/m) and yeast (61.21 ± 4.72 to 72.13 ± 5.55 N/m). Based on these findings, brewing-derived ingredients demonstrate potential as cosmetic actives, with formulation critically determining their clinical efficacy. Full article

As consumer attitudes shift, non-alcoholic and low-alcohol beers (NABLABs) have grown rapidly in popularity. This has driven interest in biological production methods that avoid the cost and flavor damage associated with post-fermentation dealcoholization. This review focuses on how barley wort composition and process conditions shape the metabolism of maltose- and maltotriose-negative non-Saccharomyces yeasts (NSYs), and how this, in turn, affects ethanol yield, flavor, and aroma in NABLABs. Key sections examine differences in carbohydrate utilization between Saccharomyces and NSYs, the influence of oxygen and Crabtree/Kluyver effects on carbon flux, and the roles of glycerol and organic acid formation as alternate carbon sinks that also contribute to mouthfeel, sweetness perception, and acidity. Particular attention is given to mashing strategies and enzyme additions used to redesign wort sugar profiles for NSYs, including high-temperature, low-gravity mashes and exogenous amyloglucosidase to increase glucose while limiting maltose and ethanol formation. The review also summarizes how the NSY-driven production of esters, higher alcohols, and the biotransformation of hop-derived precursors can offset excessive sweetness and “worty” off-flavors that commonly affect NABLABs. The use of NSYs opens an exciting array of opportunities for brewers to make NABLABs; however, challenges remain. Saccharomyces yeasts have centuries of brewing experience behind them and the adaptations needed for effective use of NSYs are still in development. Fundamentally, the challenge for NABLAB brewers using biological methods is to balance the desirable effects of fermentation while maintaining ethanol levels below the target threshold. This review outlines those challenges in detail and examines some of the approaches that are being used to solve them. Full article

A total of 35 commercially available beers (of various beer styles) produced in Poland were analysed in this study to assess the concentration of xanthohumol and isoxanthohumol, prenylated flavonoids originating from the hops, which are known to possess multiple health-benefitting properties. High-performance liquid chromatography coupled with a UV/VIS DAD detector was utilised to identify and quantify hop flavonoids. Additionally, physicochemical parameters, such as wort extract content, extract content, alcohol content, and degree of attenuation, were analysed in all the samples. The xanthohumol content of the Polish beers varied the most from the analysed flavonoids and ranged from 0.029 to 2.459 mg per L of the beer. The concentration of the isoxanthohumol was, on average, higher and ranged from 0.621 to 2.510 mg per L. Full article

The growing interest in functional beer production has led to the exploration of unconventional raw materials, such as hemp (Cannabis sativa L.), for brewing applications. This study aimed to evaluate the volatile organic compound (VOC) profile and the macro- and microelement composition of barley wort enriched with varying proportions (10% and 30%) of malted and unmalted hemp seeds, using solid-phase microextraction followed by gas chromatography–mass spectrometry (SPME–GC–MS) and atomic absorption spectrometry (AAS). A total of 64 VOCs were identified across four wort variants: control (barley malt only), 10% malted hemp, 30% malted hemp, and 30% unmalted hemp. The aroma profile was significantly influenced by compounds such as 2,3-butanediol, 1-hexanol, 3-methyl-1-butanol, 3-hydroxy-2-butanone, hexanoic acid, and 4-vinylguaiacol (p < 0.001). Principal component analysis (PCA) revealed clear separation between wort types based on the relative abundance of alcohols, acids, ketones, and phenols, indicating a progressive shift from sweet/malty toward acidic, green, and herbal aroma notes as hemp addition increased. Notably, unmalted hemp seeds resulted in a pronounced dominance of hexanoic acid, which may contribute to earthy and rancid sensory attributes. The evaluation of selected mineral elements showed that the key macroelements differentiating the worts were potassium, magnesium, phosphorus, and calcium, while among the microelements the distinguishing elements were manganese, iron, and sodium. These findings demonstrate the strong modulating effect of aromatic hemp-derived materials on the aroma composition and selected mineral content of brewing worts, supporting their targeted use in novel beer formulations. Full article

Hop polyphenols contribute to beer stability and possess a wide range of biological activities; however, information on how extraction conditions influence their recovery and antioxidant potential remains limited. This study aimed to compare hot-water extraction, simulating wort boiling, with 80% aqueous acetone extraction as initial sample preparation steps for assessing the polyphenol content and antiradical activity of hops. Sample sets of four Czech hop cultivars from two contrasting harvest years were examined. Group-type polyphenols, total polyphenols, anthocyanogens, flavanoids and UHPLC–HRMS flavonoid profiles were evaluated. Antiradical activity was evaluated by the DPPH assay. Extraction solvent markedly affected both the composition and antiradical properties of hop extracts. Aqueous acetone provided substantially higher yields of anthocyanogens and prenylflavonoids and consistently higher antiradical activity, particularly in cultivars with elevated α-acid content. In contrast, hot-water extracts yielded slightly higher total polyphenols but significantly lower anthocyanogens and reduced antioxidant capacity. Correlation analyses showed that antiradical activity in water extracts was strongly driven by polyphenol levels, whereas in acetone extracts it was influenced by additional constituents, including bitter acids. Extraction solvent critically determines the polyphenolic profile and antioxidant behavior of hop extracts. Aqueous acetone proved more effective for isolating bioactive polyphenol fractions relevant to antiradical performance. Full article

Umami taste in lager beer not only determined body fullness and the backbone of aftertaste, but also affected the controllability and interpretability of flavor expression across the entire brewing process. Based on stage-wise sampling, peptidomic profiles were established on wort fermentation day 0, day 1, day 3, and day 9. A total of 25,592 peptides were identified by reversed-phase liquid chromatography–quadrupole time-of-flight mass spectrometry (RPLC-QTOF-MS). Molecular informatics screening was performed using UMPred-FRL (a feature representation learning-based meta-predictor for umami peptides) and TastePeptides-Meta (a one-stop platform for taste peptides and prediction models), yielding 7255 potential umami peptides. From these, 145 peptides were further selected for molecular docking. In addition, 6 representative umami peptides were selected for receptor-level validation and structural analysis. Mechanistically, the umami receptor taste receptor type 1 member 1/taste receptor type 1 member 3 (T1R1/T1R3) belonged to class C G protein-coupled receptor (GPCR) and relied on the extracellular Venus flytrap (VFT) domain for ligand capture. Ligand-induced VFT conformational convergence transmitted changes to the transmembrane region and triggered signal transduction. Docking and energy decomposition indicated that the ionic group primarily contributed to orientation and anchoring. Salt-bridge or hydrogen-bond networks were formed around Lys228, Arg240, Glu206, Asp210, Asn141, and Gln138, thereby reducing conformational freedom. Meanwhile, hydrophobic side chains obtained major binding gains within a hydrophobic microenvironment formed by Val135, Ile137, Leu165, Tyr166, Trp78, and His79. These results reflected a synergistic mode in which charge pairing enabled positioning and hydro-phobic complementarity promoted VFT closure. To experimentally confirm sensory relevance, 6 representative peptides were individually spiked into 4 brewing-stage beer samples, which produced a clear stratification pattern across stages. Notably, peptides with favorable docking-derived binding propensity did not necessarily enhance umami perception, and several longer peptides showed persistent negative sensory shifts, supporting that binding affinity alone could not be treated as a proxy for perceived umami in the beer matrix. At the node level, the cumulative abundance of umami peptides showed a significant positive correlation with umami scores, with a Pearson correlation coefficient of r = 0.963 and p = 0.037. This result indicated good linear consistency between umami peptide content and the upward shift in umami taste in lager beer. Umami peptide clusters were further proposed as a more appropriate functional unit, and an umami peptide cluster database spanning the full process was constructed. This database provided a reusable resource for process control and flavor prediction. Full article

This study aims to identify an effective neural network architecture for the task of semantic segmentation of the surface of beer wort at the stage of primary fermentation, using deep learning methodologies. Four contemporary architectures were evaluated and contrasted. The following networks are presented in both baseline and optimized forms: U-Net, DeepLabV3+, Fast-SCNN, and SegNet. The models were trained on a dataset of images depicting real beer surfaces at the primary fermentation stage. This was followed by the validation of the models using key metrics, including pixel classification accuracy, Mean Intersection over Union (mIoU), Dice Coefficient, inference time per image, and Graphics Processing Unit (GPU) resource utilization. Results indicate that the optimized U-Net achieved the optimal balance between performance and efficiency, attaining a validation accuracy of 88.85%, mIoU of 76.72%, and a Dice score of 86.71%. With an inference time of 49.5 milliseconds per image, coupled with minimal GPU utilization (18%), the model proves suitable for real-time deployment in production environments. Conversely, complex architectures, such as DeepLabV3+, did not yield the anticipated benefits, thereby underscoring the viability of utilizing compact models for highly specialized industrial tasks. This study establishes a novel quantitative metric for the assessment of fermentation. This is based on the characteristics of the foam surface and thus offers an objective alternative to traditional subjective inspections. The findings emphasize the potential of adapting optimized deep learning architectures to quality control tasks within the food industry, particularly in the brewing sector, and they pave the way for further integration into automated computer vision systems. Full article

Intracellular metabolites markedly change in yeast during fermentation, especially under various stresses in beer post-fermentation. To address the current limitations in understanding the regulatory mechanisms in this complex environment, industrial brewing yeast was analyzed using integrated transcriptomics and proteomics across the post-fermentation phases, dynamically profiling the transcriptional levels and protein abundances of differentially expressed genes. As a result, 6110 differentially expressed genes (DEGs) and 3533 differentially expressed proteins (DEPs) were identified. Additionally, transcriptomics showed the induced expression of low-pH- and oxidative stress-related genes (HAL1, HAL4, YAP5), gluconeogenesis- and sugar transport-related genes (HXT, MAL, FBP), and mannan synthetic genes (FSK, MNN) during early post-fermentation. Moreover, heat-shock-related genes were upregulated throughout post-fermentation. Furthermore, proteomics revealed the sustained upregulation of glucosidase Scw, mannoprotein Pir, hexose transporter Hxt, and heat-shock proteins (Hsp). These findings indicate that yeast adapts to stress in the wort environment during post-fermentation by enhancing cell wall biosynthesis, activating heat-shock responses, and modulating metabolic pathways. These integrated omics analyses provide guidance for selecting robust, tolerant strains to industrial-scale stresses and improving beer flavor profiles, establishing a theoretical foundation for optimizing brewing and enhancing beer quality. Full article

Beer is a drink that has been a staple in human history, evolving from its beginning in antiquity to the present day. Nowadays, large breweries and other companies have set up laboratories focused on finding and developing new yeast strains for the brewing sector to meet consumers’ demand for new beer styles. Monascus spp. are ascomycota that have been known for hundreds of years. They are widely popular in Asian cuisine, especially in fermented foods. Studies show that Monascus spp. produce numerous food dyes and substances that positively influence human health. In the presented work, Monascus ruber was tested as a potential microorganism for the beer industry. Experiments included fermentation trials with Monascus ruber in four regimes: in aerobic condition, anaerobic condition, anaerobic condition with pH kept above 4.5, and in anaerobic condition with pH set to 4.5. As a reference, commercial Saccharomyces cerevisiae and Saccharomyces pastorianus were used. Fermentation parameters were evaluated by measurements of ethanol and extract level. The final product was tested for its colour in order to evaluate if monascus-derived pigments were present in the beverage. Moreover, a qualitative analysis of lovastatin and citrinin was performed in order to check if those monascus metabolites were present. Finally, small-scale consumer tests were performed in order to check the organoleptic properties of the obtained beverage. Results show that Monascus ruber is able to ferment beer wort in a similar manner as Saccharomyces strains, reaching a slightly lower degree of attenuation. Nevertheless, a longer lag phase was observed in monascus trials, except for the trial with preset pH at 4.5. The most visible change in the product was a reddish colour that appeared in the sample in aerobic conditions. The qualitative analysis showed that lovastatin and citrinin were present in the tested samples. Consumer tests show that experimental beer has a different taste than Saccharomyces-fermented products. Although the presented results are preliminary, they could be a good starting point for further research on monascus-based beverages. Full article

Recently acquired evidence indicates that bacteria can utilise yeasts as survival niches. This study investigated the presence of hidden, intracellular bacteria (endobacteria) within wild yeasts collected from natural ecosystems and evaluated whether biotechnological processes influenced these bacterial communities. We examined the microbiotas of 28 axenic cultures of wild yeasts; these were selected due to their potential brewing and biocontrol uses and were isolated from habitats associated with Quercus and Vitis. We also analysed the microbiotas present after these strains were used to ferment beer wort. Bacterial communities were characterised using 16S rRNA gene amplicon metagenomics. The results indicate that yeast strains and their endobacterial partners have coevolved, and their compositions are shaped by the environmental conditions. Substantial bacterial diversity was detected across strains in both axenic cultures and post-fermentation samples. The ecological origin of the yeast (oak- or grape-associated) did not significantly affect the endobacterial community structure. Across all samples, the dominant phyla were Proteobacteria, Actinobacteria, Firmicutes, and Cyanobacteria, with Proteobacteria representing over 90% of sequences. Most bacterial genera were shared between axenic and fermentation conditions. However, Escherichia and Comamonas predominated in axenic cultures, while Parvibaculum dominated after fermentation. These findings suggest that yeasts constitute stable microhabitats for bacterial communities, and their relative abundances can shift during fermentation processes. Full article