Search Results (1,070)

The purified yeast strain H4, identified as W. anomalus through morphological, genetic, and phylogenetic analyses, was characterized and compared to a commercial Saccharomyces cerevisiae strain X16. W. anomalus H4 exhibited distinct morphological features. It demonstrated notable tolerance to 11% ethanol, 220 g/L glucose, and 200 mg/L octanoic acid, similar to X16, except for having a lower tolerance to SO₂. Survival analysis under various stress conditions revealed that ethanol and octanoic acid had the most detrimental effects, with 56% cell mortality at 13% ethanol and 400 mg/L octanoic acid. Transcriptomic analysis under octanoic acid stress showed that at 200 mg/L, 3369 differentially expressed genes (DEGs) were induced, with 1609 being upregulated and 1760 downregulated, indicating broad transcriptional reprogramming. At 400 mg/L, only 130 DEGs were detected, suggesting a more limited response. KEGG pathway analysis indicated that most DEGs at 200 mg/L were associated with the “ribosome” and “proteasome” pathways, reflecting disruptions in protein synthesis and turnover. At 400 mg/L, the DEGs were primarily related to “DNA replication” and “pyruvate metabolism”. These findings highlight the adaptive mechanisms of W. anomalus H4 to environmental stresses, particularly octanoic acid, and its potential for use in brewing and fermentation processes. Full article

Using drone cells to optimize Radio Access Networks is an exemplary way to enhance the capabilities of terrestrial Radio Access Networks. Drones fitted with communication and relay modules can act as drone cells to provide an unobtrusive network connection. The multi-drone-cell placement problem is solved using adapted Dispersive Flies Optimization alongside other meta-heuristic algorithms such as Particle Swarm Optimization and differential evolution. A home-brewed simulator has been used to test the effectiveness of the different implemented algorithms. Specific environment respective parameter tuning has been explored to better highlight the possible advantages of one algorithm over the other in any particular environment. Algorithmic diversity has been explored, leading to several modifications and improvements in the implemented models. The results show that by using tuned parameters, there is a performance uplift in coverage probability when compared to the default meta-heuristic parameters while still remaining within the constraints implied by the problem’s requirements and resource limitation. This paper concludes by offering a study and comparison between multiple meta-heuristic approaches, investigating the impact of parameter tuning as well as analyzing the impact of intermittent restarts for the algorithms’ persistent diversity. Full article

The main objective of this experiment was to investigate the technological potential of upcycling unsparged non-conventional brewers’ spent grains (BSGs) in bread-making and assess the comparative quality of bread enriched with non-fermented and lactic acid-fermented BSGs obtained from mashes brewed with starch adjuncts of buckwheat and oats. After the runoff of the first wort, unsparged non-conventional BSGs with approximately 75% moisture, acidic pH, and yield in the soluble extract above 56.6% (w/w d.m.) were used in substituting wheat flour with 5 and 15% (w/w d.m.) in bread-making recipes. The highest loaf volume value (318.68 cm³/100 g) was observed for 5% fermented buckwheat-BSG addition. Except for the samples with 5% fermented BSGs, specific volumes decreased. Crumb moisture was reduced by up to 22% for all samples, with this parameter related to bread weight. Bread porosity, elasticity, acidity, and overall sensory acceptability were better for fermented than non-fermented BSGs. The results proved that non-conventional BSGs with buckwheat and oats addition have the potential to be valorized in new bread assortments, and lactic acid fermentation applied to the BSGs is beneficial, even for overall sensory acceptability and quality of baked end-products. Technological, buckwheat-BSG was more convenient than oats-BSG. Further research continues to optimize and upscale Technology Readiness Levels. Full article

Chlorella vulgaris, a microalga rich in secondary metabolites and nutrients, offers a promising alternative for promoting microbial growth in food fermentation processes. This study aimed to evaluate the effects of C. vulgaris extracts on fermentation kinetics, sensory characteristics, phytochemical composition, antioxidant activity, and the abundance of volatile organic compounds (VOCs) in treated versus control beers. The bioactive compounds from C. vulgaris were extracted using an ultrasound-assisted method with water as the solvent. A German Pilsner-style lager beer (GPB) was brewed and supplemented with 0.5, 1, and 5 g/L of C. vulgaris extracts prior to primary fermentation. Yeast viability, °Brix, and pH levels were monitored to assess fermentation progress. Phytochemical composition was analyzed by quantifying total polyphenols and flavonoids. The antioxidant activity of the beer was evaluated using both the 2,2-diphenyl-1-picrylhydrazyl (DPPH^●) and hydrogen peroxide assays. The addition of C. vulgaris extracts resulted in increased yeast viability and slight variations in gravity during the 7-day fermentation period. Moreover, the beers supplemented with C. vulgaris extracts demonstrated higher levels of total polyphenols, flavonoids, and antioxidant activity compared to the GPB. Specific volatile organic compounds, including 2-methyl-1-propanol, 1-hexanol, isopentyl hexanoate, 2-methylpropyl octanoate, β-myrcene, and geranyl acetate, were significantly more abundant (p < 0.05) in the treated beers than in the control. Sensory evaluations revealed a favorable impact of the treatment on aroma scores compared to the GPB. Overall, the findings indicate that C. vulgaris extracts could be a valuable ingredient for developing functional beers with enhanced health benefits, particularly regarding antioxidant activity. Additionally, the results underscore the importance of exploring innovative approaches that utilize natural sources like Chlorella to enrich the nutritional profile and sensory qualities of fermented products. Full article

This paper integrates $L_1$-norm structural risk minimization with $L_1$-norm approximation error to develop a new optimization framework for solving the parameters of sparse kernel regression models, addressing the challenges posed by complex model structures, over-fitting, and limited modeling accuracy in traditional nonlinear system modeling. The first $L_1$-norm regulates the complexity of the model structure to maintain its sparsity, while another $L_1$-norm is essential for ensuring modeling accuracy. In the optimization of support vector regression (SVR), the $L_2$-norm structural risk is converted to an $L_1$-norm framework through the condition of non-negative Lagrange multipliers. Furthermore, $L_1$-norm optimization for modeling accuracy is attained by minimizing the maximum approximation error. The integrated $L_1$-norm of structural risk and approximation errors creates a new, simplified optimization problem that is solved using linear programming (LP) instead of the more complex quadratic programming (QP). The proposed sparse kernel regression model has the following notable features: (1) it is solved through relatively simple LP; (2) it effectively balances the trade-off between model complexity and modeling accuracy; and (3) the solution is globally optimal rather than just locally optimal. In our three experiments, the sparsity metrics of $SVs\%$ were 2.67%, 1.40%, and 0.8%, with test RMSE values of 0.0667, 0.0701, 0.0614 (sinusoidal signal), and 0.0431 (step signal), respectively. This demonstrates the balance between sparsity and modeling accuracy. Full article

Background: Common hops (Humulus lupulus L.) play a key role in brewing, providing the bitterness, flavor, and aroma of beer, and are widely used in supplements for their antibacterial, anti-inflammatory, and antioxidant properties. However, despite their broad applications, the allergenic potential of common hops remains underexplored, particularly when compared to the closely related Humulus japonicus. This preliminary study aimed to investigate the allergenic potential of common hops and their potential cross-reactivity with common pollen allergens. Methods: The immunoreactivity of hop stalks, leaves, and cones was assessed using antibodies against major allergens from birch (Bet v1a), mugwort (Art v1), and timothy grass (Phl p5b), as well as three sera from pollen-allergic patients. Slot Blot analysis was performed using phosphate-buffered saline extracts from the stalks, leaves, and cones of three hop cultivars, while Western Blotting followed SDS-PAGE protein separation. Results: The results revealed significant immunoreactivity in native hop proteins, with diminished reactivity observed in denatured proteins. Cross-reactivity between hop proteins and major pollen allergens was confirmed, indicating that hop proteins may contribute to allergic sensitization in pollen-sensitive individuals. Conclusions: These findings underscore the potential allergenic risks associated with the consumption or exposure to hop-containing products. Full article

The diversity of the microbial community structure plays a crucial role in the flavor and nutritional value of Shanxi aged vinegar in fermentation. Illumina Miseq high-throughput sequencing identified thirteen bacterial genera, with Lactobacillales (44.89%) and Acetobacter (21.04%) being the predominant species. Meanwhile, the fermentation characteristics of selected lactic acid bacteria strains isolated from Shanxi aged vinegar were studied in different media. The results showed that the biomass, and physical and chemical indices, as well as flavor compounds of the four strains of lactic acid bacteria in the simulated vinegar fermented grains medium were superior to those in barley and pea medium and sorghum juice medium. The bacterial interaction was conducted to investigate the effects on growth, the physicochemical indices, and flavor substances in order to determine the optimal combination. Furthermore, the interaction between pure cultures and co-cultures of lactic acid bacteria in a simulated vinegar culture medium was investigated, with a focus on the impact of this interaction on strain growth, fermentation characteristics, and flavor compound production. Compared with the pure culture, when strains L7 and L729 were co-inoculated, the reducing sugar content was 0.31 ± 0.01 g/100 g, total acid content was 3.02 ± 0.06 g/100 g, acetoin content was 2.41 ± 0.07 g/100 g, and total organic acid content was 3.77 ± 0.17 g/100 g. In terms of flavor compounds, the combined culture system exhibited higher levels of esters, aldehydes, and acids compared to pure cultures or other co-culture systems. This study revealed the fermentation characteristics of selected lactic acid strains in Shanxi aged vinegar under different conditions and their interaction in simulated vinegar fermentation media, which could provide theoretical support for the safety and health evaluation of aged vinegar. Full article

The well-known hop variety, Saaz, which gives the Pilsner lager beer its characteristic hop aroma, may be threatened by climate change in the future. Therefore, new Saaz-related hop varieties, including Saaz Late, Saaz Brilliant, Saaz Comfort, and Saaz Shine, were recently bred. A comparison study was carried out to evaluate whether these varieties are acceptable for traditional lagers. For this purpose, sensorial and chemical analyses of hops and related beers, namely, an analysis of hop resins and oils, were performed. Sensory profiles of Saaz varieties are very similar (fine, hoppy aroma; floral; herbal), except for Saaz Comfort, which has a slightly higher aroma intensity, and Saaz Shine, which has the most noticeable fruity scent, with traces of citrus. The chemical profiles are also very similar, with α-humulene, β-pinene, (E)-β-farnesene, β-caryophyllene, and myrcene being the most abundant. Decoction mashing and kettle hopping technology with bottom fermentation show that the compared varieties result in very similar lager beers with hoppy, floral, herbal, fruity, and spicy aromas. Typical hop oils include farnesol, linalool, methyl geranate, β-pinene, and limonene. The high concentration of farnesol in beer correlates with the concentrations of (E)-β-farnesene and farnesol in hops. New Saaz varieties are widely used to produce Pilsner lager without affecting the traditional sensory aroma of this widespread style. Varieties have a higher yield of approximately 25% and bitter acid concentrations of approximately 15%, with Saaz Comfort comprising approximately 100%. Furthermore, the concentration of hop oils is approximately 40% higher in Saaz Shine than a traditional Saaz variety. Moreover, Saaz Shine and Saaz Comfort have very good resistance to drought, which is an important property from a climate change perspective. Full article

Yearly, thousands of tons of wasted coffee grounds are produced according to high coffee consumption. Still, after the coffee brewing, wasted coffee grounds contain some amounts of caffeine (CAF). CAF, in turn, contains multiple O and N chelating atoms in its structure. These have a potential to be reductors for complexes of metals. In this context, within the present study, a set of CAF extracts derived from coffee beans and coffee grounds were obtained and then used for the one-step reduction of ReO₄⁻ ions with no additional toxic chemicals. Within this approach, CAF was applied as a secondary, green resource for the synthesis of unique rhenium nanoparticles (ReNPs) containing Re species at 0 and +6 oxidation states. The obtained ReNPs were identified and characterized with the use of X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Further, the capping and stabilization of ReNPs by CAF were verified with the aid of Fourier transformation infrared spectroscopy (FT-IR). The so-obtained “green” ReNPs were then used as a homogenous catalyst in the catalytic hydrogenation of 4-nitrophenol (4-NP). This new nanomaterial revealed a superior catalytic activity, leading to the complete reduction of 4-NP to 4-aminophenol within 40–60 min with a first-order rate constant of 0.255 min⁻¹. Full article

Global urbanization, population growth, and climate change have considerably impacted water resources, making sustainable water resource management (WRM) essential. Understanding the changes in hydrological components is important for effective WRM, particularly in cities such as Higashi-Hiroshima, which is known for its saké brewing industry. This study used the Soil and Water Assessment Tool (SWAT) with Hydrological Response Units (HRUs) to achieve high spatial precision in assessing the impacts of land use change and climate variability on hydrological components in a suburban catchment in western Japan. Over the 30-year study period (1980s–2000s), land use change was the main driver of hydrological variability, whereas climate change played a minor role. Increased surface runoff, along with decrease in groundwater recharge, evapotranspiration, and baseflow, resulted in an overall reduction in water yield, with a 34.9% decrease in groundwater recharge attributed to the transformation of paddy fields into residential areas. Sustainable WRM practices, including water conservation, recharge zone protection, and green infrastructure, are recommended to balance urban development with water sustainability. These findings offer valuable insights into the strategies for managing water resources in rapidly urbanizing regions worldwide, emphasizing the need for an integrated WRM system that considers both land use and climate change impacts. Full article

To investigate the dynamic changes and potential correlations between microbial diversity and volatile organic compounds (VOCs) during Chinese medium-temperature Daqu (MTD) manufacturing at different key stages, in this study, high-throughput sequencing (HTS) and gas chromatography–ion mobility spectrometry (GC–IMS) were employed to analyze the microbial diversity and VOCs of MTD, respectively. The results showed that Weissella, Staphylococcus, Thermoactinomyces, Kroppenstedtia, and Lactobacillus were the dominant bacterial genera, while Aspergillus, Alternaria, Thermoascus, Thermomyces, Wickerhamomyces, and Saccharomyces were the dominant fungal genera. A total of 61 VOCs were detected by GC–IMS, among which, 13 differential VOCs (VIP > 1) were identified, that could be used as potential biomarkers to judge the fermentation stage of MTD. Kroppenstedtia and Saccharopolyspora were positively correlated with 3-methyl-2-butenal and 2,2,4,6,6-pentamethylheptane-D, respectively, and both of these were positively correlated with butanal-D. Acetobacter, Streptomyces, and lactic acid bacteria (LAB) including Leuconostoc, Pediococcus, Weissella, and Lactobacillus were negatively correlated with their associated VOCs, while fungi were generally positively correlated with VOCs. Wickerhamomyces, Saccharomyces, and Candida were positively correlated with butan-2-one-M. This study provides a theoretical basis for explaining the mechanisms of MTD flavor formation and screening functional microorganisms to improve the quality of MTD. Full article

Obligate anaerobic beer spoilage bacteria have been a menace to the brewing industry for several decades. Technological advances in the brewing process aimed at suppressing aerobic spoilers gave rise to problems with obligate anaerobes. In previous studies, the metabolic spectrum of Pectinatus and Megasphaera species has been described, but their metabolism in the beer environment remains largely unknown. We used high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GCMS) to further characterize beer spoiled by 30 different strains from six beer-spoiling species of Pectinatus and Megasphaera (P. cerevisiiphilus, P. frisingensis, P. haikarae, M. cerevisiae, M. paucivorans, and M. sueciensis). We detected differences in carbohydrate utilization and the volatile organic compounds (volatilome) produced during beer spoilage by all six species. We were able to show that glycerol, one of the basic components of beer, is the common carbon source used by all strains. It appears that this carbon source allows for anaerobic beer spoilage by Pectinatus and Megasphaera despite the spoilage-preventing intrinsic barriers of beer (iso-α-acids, ethanol, low pH, scarce nutrients); thus, extrinsic countermeasures are key for prevention. Full article

Hierarchical porous carbon derived from discarded biomass for energy storage materials has attracted increasing research attention due to its cost-effectiveness, ease of fabrication, environmental protection, and sustainability. Brewed tea leaves are rich in heteroatoms that are beneficial to capacitive energy storage behavior. Therefore, we synthesized high electrochemical performance carbon-based composites from Tie guan yin tea leaf waste using a facile procedure comprising hydrothermal, chemical activation, and calcination processes. In particular, potassium permanganate (KMnO₄) was incorporated into the potassium hydroxide (KOH) activation agent; therefore, during the activation process, KOH continued to erode the biomass precursor, producing abundant pores, and KMnO₄ synchronously underwent a redox reaction to form MnO nanoparticles and anchor on the porous carbon through chemical bonding. MnO nanoparticles provided additional pseudocapacitive charge storage capabilities through redox reactions. The results show that the amount of MnO produced is proportional to the amount of KMnO₄ incorporated. However, the specific surface area of the composite material decreases with the incorporated amount of KMnO₄ due to the accumulation and aggregation of MnO nanoparticles, thereby even blocking some micropores. Optimization of MnO nanocrystal loading can promote the crystallinity and graphitization degree of carbonaceous materials. The specimen prepared with a weight ratio of KMnO₄ to hydrochar of 0.02 exhibited a high capacitance of 337 F/g, an increase of 70%, owing to the synergistic effect between the Tie guan yin tea leaf-derived activated carbon and MnO nanoparticles. With this facile preparation method and the resulting high electrochemical performance, the development of manganese oxide/carbon composites derived from tea leaf biomass is expected to become a promising candidate as an energy storage material for supercapacitors. Full article

In recent years, demand for low-alcohol and alcohol-free beers has been rising. Of the many methods of producing such beers, many have expensive implementation requirements or drawbacks in terms of beer quality. The exploration of non-Saccharomyces yeast species presents a promising opportunity to overcome these challenges. These yeasts, with their diverse metabolic capabilities and unique flavor profiles, offer the potential to create innovative and flavorful low-alcohol beers. The study investigates the feasibility of using selected non-Saccharomyces yeasts for brewing low-alcohol beers, focusing on fermentation kinetics, physicochemical parameters, and the sensory attributes of the final product. The evaluated yeast species were Kluyveromyces lactis MG971263, Metschnikowia pulcherrima MG971247 and MG971250, Torulaspora delbrueckii MG971248, Wickerhamomyces anomalus MG971261, and W. onychis MG971246. Two strains of Saccharomyces cerevisiae were used as a control. The results of the study show that selected non-Saccharomyces yeast species might be used to produce low-alcohol beers. The non-Saccharomyces yeast allowed the researchers to obtain beers with an alcohol content in the range of 0.5–1.05%, while the control beer brewed with US-05 had an alcohol content of 3.77%. Among the evaluated strains, the strains M. pulcherrima MG971250 and T. delbrueckii MG971248 were found to be rated better in a sensory evaluation than the brewed and low-alcohol strains of S. cerevisiae. Full article

Non-alcoholic beer is becoming more and more popular every year. Due to the high demand for such drinks, numerous breweries decided to produce non-alcoholic beer. There are various methods to create a beer with a reduced alcohol content. Among them are biological methods influencing the biochemistry of the brewing process and physical methods focused on removing ethanol from ready beer. Thus far, the most popular methods are vacuum rectification and reverse osmosis. This work evaluated another method called pervaporation for non-alcoholic beer production. During the study, low-alcohol beer (0.58 vol.%) was achieved from standard beer (3.62 vol.%) using pervaporation. The colour of the product remained unchanged at level 7 EBC. The concentration of ferulic acid decreased from 11.5 to 9.1 mg/dm³, and maltol was concentrated, reaching a concentration of 38 mg/dm³ in the final retentate during a 5 h process. Full article