Search Results (623)

Sea fennel (Crithmum maritimum L.) is an emerging crop valued for its nutritional and sensory properties and has been reported to exert health-promoting effects, including antioxidant, anti-inflammatory, antimicrobial, and cardioprotective activities, as well as potential benefits for gut health and metabolic regulation. Building on these features, the present study aimed to unlock the potential of sea fennel to produce novel pickles. Two independent batches were prepared using young leaves and stems of sea fennel fermented in brine. After fermentation, salt concentration was standardized in all prototypes, and two types of vinegar (apple and wine) were added at four acetic acid levels (0.05%, 0.2%, 0.5%, and 0.7%). All prototypes were subsequently subjected to mild pasteurization. During fermentation, physicochemical and microbiological parameters were monitored, while after pasteurization additional physicochemical, microbiological, volatile organic compound (VOCs), and sensory analyses were performed during storage. In both batches and across all prototypes, fermentation resulted in a significant pH decrease, dominance of lactic acid bacteria, inhibition of Enterobacteriaceae, and a gradual increase in yeasts. Following vinegar addition and pasteurization, pH, titratable acidity, and salt content remained stable over six months of storage in most prototypes, particularly those with 0.2% acetic acid. Pasteurization effectively inactivated lactic acid bacteria and Enterobacteriaceae in all prototypes, whereas yeasts and mesophilic bacteria persisted in low-acidity samples (0.05%). Therefore, the 0.05% acidity samples were later excluded due to mid-stage microbial spoilage. Batch-dependent differences were observed in color and sensory attributes, with batch 2 showing higher overall stability mainly in acidic flavor and aroma, particularly in prototypes with 0.2% acidity. VOCs analysis revealed profiles primarily driven by batch variation, with secondary modulation by vinegar type: sesquiterpenes remained stable, while γ-terpinene, limonene, and p-cymene were the dominant compounds, with greater stability observed in batch 2. Overall, the combined use of lactic acid fermentation, vinegar pickling, and mild pasteurization represents a promising strategy for preserving sea fennel and supports its potential as a vegetable crop. Full article

The effect of cold smoking on the physicochemical, microbiological, and aromatic properties of Formaella-type cheese has not been previously investigated. In this study, experimental Formaella-type hard cheeses (≤38% moisture) were produced using a multistep high-temperature cooking process and subjected to weak (20 min) and intense (60 min) cold smoking, alongside an unsmoked control. Cheeses were analyzed before and after smoking and during refrigerated storage (up to 90 days). Smoking significantly influenced pH, water activity, and colour parameters, with intensively smoked cheeses exhibiting lower pH, reduced lightness (L*), and increased redness (a*) and yellowness (b*). Microbiological analyses revealed low viable counts across all samples, attributed to severe cooking steps and vacuum storage. Smoking, particularly at high intensity, significantly reduced total mesophilic counts and enterococci, while Enterobacteriaceae, staphylococci, yeasts, and moulds were not detected after manufacture. The dominant microbiota consisted mainly of lactic acid bacteria, identified by MALDI-TOF MS, including Enterococcus durans, Ent. faecium, Leuconostoc lactis, Leuconostoc mesenteroides, Streptococcus thermophilus, Lacticaseibacillus rhamnosus, and Lactobacillus curvatus. Headspace-SPME-GC-MS analysis identified 75 volatile compounds, with free fatty acids, ketones, aldehydes, and lactones as the predominant groups. Smoking introduced characteristic phenolic and furan derivatives associated with smoky aroma. Overall, smoking intensity modulated microbial dynamics and aroma development without compromising microbiological quality. Full article

Plant fungal diseases, such as apple tree canker caused by Valsa mali, have caused severe losses in agricultural production. Traditional chemical fungicides induce drug resistance in pathogens and cause environmental pollution. Therefore, it is of substantial importance to screen efficient and environmentally friendly bacterial strains as potential biocontrol agents. The tea rhizosphere harbors abundant microbial resources, and previous research has identified microorganisms with antifungal activity existing in this environment. Therefore, in this study, we isolated antagonistic bacteria with broad-spectrum biocontrol potential from tea rhizosphere soil. In this study, a strain with strong antagonistic activity against V. mali was isolated from tea rhizosphere soil. Based on morphological characteristics, 16S rRNA gene sequencing, and whole-genome analysis, the isolated strain was identified as Bacillus velezensis and designated as LW-66. This strain demonstrated broad-spectrum antifungal activity against various plant pathogenic fungi, including Valsa mali, Fusarium graminearum, Bipolaris sorokinianum, Alternaria solani, and Exserohilum turcicum. The active extract of B. velezensis maintained strong stability across a wide range of temperatures (25–90 °C) and pH values (2–8), with stability decreasing only when the temperature reached 100 °C or pH ≥ 10. In a preventive assay using detached apple branches inoculated with V. mali, the control efficacy of LW-66 against apple tree canker reached more than 90%. Additionally, in a therapeutic assay using V. mali-infected potted apple seedlings, the LW-66 bone-glue bacterial agent achieved a survival rate of up to 90%. Whole-genome analysis revealed that the genome of LW-66 contains 13 predicted secondary metabolite biosynthetic gene clusters, seven of which showed high homology (≥92% similarity) with known antimicrobial gene clusters, including surfactin, bacillaene, macrolactin H, fengycin, difficidin, bacillibactin, and bacilysin. These gene clusters may be connected to the broad-spectrum antifungal activity of B. velezensis, as well as its ability to disrupt hyphal morphology. The volatile organic compounds produced by LW-66 inhibited V. mali growth by 91.70%. Collectively, these findings demonstrate that B. velezensis LW-66 has a wide antimicrobial range and strong antagonistic effects against multiple plant pathogenic fungi. Therefore, B. velezensis shows promise as a biocontrol agent for managing fungal diseases in plants, providing a basis for developing LW-66-derived biocontrol products aimed at controlling diseases such as apple tree canker. Full article

Artisanal cheese quality relies on a complex microbiota. The generalized use of commercial starter cultures has been associated with reduced microbial diversity, fueling interest in using indigenous lactic acid bacteria (LAB) as adjunct cultures. This study aimed to evaluate Ligilactobacillus salivarius SP36 as a starter or adjunct culture in ripened cheeses. Culture-based and culture-independent analyses were performed, together with the assessment of some physico-chemical parameters (pH, water activity, and color), including the profile of volatile compounds. All cheeses were microbiologically safe according to current EU legislation. The pH of the cheese made only with the SP36 strain was higher than those of the cheeses manufactured with a commercial starter (with or without strain SP36). L. salivarius SP36 modulated the aroma profile by increasing ethyl esters, alcohols, ketones, organic acids and sulphur compounds. LAB dominated all cheeses, with the highest microbial diversity in the cheese produced without the commercial starter. Lactiplantibacillus plantarum and Lacticaseibacillus paracasei isolates were obtained from all cheeses. Overall, L. salivarius SP36 seems a promising adjunct for mature cheeses, while autochthonous L. plantarum and L. paracasei isolates represent promising candidates for starter or adjunct cultures. Full article

Water kefir grains are complex probiotic granules that can efficiently ferment fruit and vegetable juices and significantly improve product flavor. However, the mechanisms of flavor formation remain unclear, which limits the process optimization of this technology. This study investigated the mechanisms involved in flavor formation during the fermentation of strawberry juice with water kefir grains. The results showed that as fermentation progressed, the total acidity increased, whereas the pH value and soluble solids content decreased. Additionally, the contents of citric acid and malic acid gradually decreased with fermentation, while the contents of lactic, acetic, and succinic acid increased, and three soluble sugars showed reduced levels. A total of 218 volatile compounds were identified. Eight dominant bacterial genera and one dominant yeast species were detected. Significant correlations between some key microorganisms and flavor compounds were observed. Specifically, Lactiplantibacillus was positively correlated with hexyl acetate. Meanwhile, Gluconobacter and Acetobacter were positively correlated with methyl (Z,Z)-9,12-octadecadienoate, isoamyl acetate, etc. In contrast, LAB such as Lacticaseibacillus and Schleiferilactobacillus showed the opposite correlations with these key flavor compounds. Saccharomyces showed a positive correlation with ethyl palmitate, ethyl propionate, phenylsuccinic acid, and 1-pentanol. The main flavor compound metabolic pathways were predicted and they were significantly related with yeasts, acetic acid bacteria, and lactic acid bacteria. Overall, this study offers a theoretical basis for the directional regulation and optimization of the flavor quality of strawberry juice fermented with water kefir. Full article

Conventional paints pose major environmental and health concerns due to their reliance on heavy-metal pigments and volatile organic compound (VOC)-emitting binders, emphasizing the need for sustainable alternatives. Previous formulations of biologic paints that combined bacteria-derived dsRED pigment protein and casein-based binders, while devoid of toxic components, suffered from prolonged drying times (~16 min), limiting their practical applicability. The present study addresses this key limitation by incorporating cellulose nanocrystals (CNC) and chitosan as biologic additives to enhance drying kinetics. Paint formulations containing 2%, 5%, and 10% of each additive were tested under controlled environmental conditions (20 °C, 60% relative humidity) following the GB/T 1728–2020 standard. Both CNC and chitosan significantly reduced drying time in a concentration-dependent manner (p < 0.001). The 10% CNC and 10% chitosan formulations achieved 61% and 44% reductions in drying time, respectively, relative to the unmodified biologic paint (12.96 ± 1.07 min at baseline). Regression analyses indicated that each 1% increase in CNC or chitosan concentration reduced drying time by 0.77 min and 0.58 min, respectively. The optimized paints exhibited acceptable drying times (5–7 min). These findings demonstrate an advancement in the development of biologically derived coatings, providing a feasible pathway toward safe and sustainable alternatives to conventional synthetic paints. Full article

Polytrichadelphus purpureus is a bryophyte distributed in tropical and subtropical regions. It represents an underexploited source of bioactive metabolites. In this study, the volatile fraction (VF) obtained by steam distillation was analyzed by gas chromatography (GC-MS and GC-FID) on a DB-5ms capillary column, identifying 86 volatile compounds, representing the 97% of the volatile profile. Sesquiterpene hydrocarbons (23.6%), alcohols (15.6%), and alkanes (14.1%) were the major group compounds. Major components include (Z)-falcarinol (14%), hexacosane (4%), β-Curcumene (3%), and oleic acid (3%), among others. In addition, the volatile fraction exhibited moderate in vitro inhibitory activity against Gram-positive bacteria (E. faecium, S. aureus), fungus A. niger at concentrations of 250 µg/mL and 500 µg/mL, respectively, and E. faecalis and L. monocytogenes (250–500 µg/mL) and a weak inhibition of acetylcholinesterase (IC₅₀: 392 µg/mL). These effects were evaluated for the first time in this species. While they are within the range reported for other plant-derived volatile fraction, they do not, on their own, justify claims of therapeutic efficacy. This study primarily advances our understanding of the genus Polytrichadelphus, suggesting potential as a source of bioactive sesquiterpenes for future phytochemical screening. Full article

Improving the flavour of soybean-based ingredients remains challenging as soybeans naturally contain compounds that generate green and beany notes. This study evaluated how the surface-growing food-grade fungus Penicillium nalgiovense (PN), alone and together with selected yeasts and lactic acid bacteria, alters the chemistry and sensory attributes of soybeans during solid-state fermentation. PN showed strong proteolytic activity in the monoculture fermentation, producing the highest accumulation of free amino acids (1324 mg/100 g), while its combination with Lactiplantibacillus plantarum (LP) further increased this to 1487 mg/100 g due to acid-assisted protease action. Sugar and organic acid profiles reflected distinct metabolic roles among the strains; for example, PNLP and PN-Debaryomyces hansenii (DH) depleted sucrose and glucose completely by 72 h, whereas DH retained substantial sucrose. Fermentation also altered the lipid profiles, where PN-Kluyveromyces marxianus (KM) showed the highest increase in polyunsaturated fatty acids, with linoleic and α-linolenic acid increasing more than twofold and threefold, respectively. Volatile analysis showed a significant decrease in hexanal (from 18.3 µg/g in control to <2.0 µg/g post fermentation) and an increase in esters, floral alcohols, and savoury compounds depending on the microbial pairing. Electronic tongue profiling showed that PN-fermented samples produced the strongest savoury taste signals. Overall, the work highlights how specific PN-yeast or PN-LAB combinations can be used to modulate flavour development in fermented soy-based substrates. Full article

Moroccan lben is a traditional spontaneously fermented milk widely consumed across the Maghreb. In this review, we synthesize data on spontaneously fermented milks from Morocco and the wider Maghreb–Middle Eastern region to infer the likely microbiota of Moroccan lben, with particular emphasis on dominant lactic acid bacteria such as Lactococcus lactis, Streptococcus thermophilus, Leuconostoc mesenteroides and lactobacilli sensu lato, alongside yeasts including Kluyveromyces marxianus and Saccharomyces cerevisiae. These communities drive a staged fermentation in which early mesophilic lactic acid bacteria (LAB) rapidly acidify the milk and initiate coagulation, intermediate heterofermentative LAB and yeasts generate key aroma compounds and mild effervescence, and late acid-tolerant lactobacilli contribute to flavor refinement and microbiological stability. We summarize how these bacteria and fungi collectively shape physicochemical, sensory and safety attributes through pH reduction, organic acid and bacteriocin production, proteolysis, and volatile formation, and discuss potential nutritional and health-related effects associated with bioactive peptides and putative probiotic strains. Finally, we identify major research gaps, including the need for high-resolution, culture-dependent and culture-independent studies, systematic safety assessments, and rational design of starter and adjunct cultures that reproduce traditional sensory profiles while improving process control. Full article

This review synthesizes recent evidence on the generation and behavior of volatile biomarkers throughout the main postharvest stages of coffee, highlighting their potential for technological standardization. During harvest, aldehydes, furans, and lactones reflect ripeness and the presence of physiological defects, thereby influencing the formation of other volatile groups in subsequent stages. During pulping and fermentation, the metabolism of yeasts and lactic and acetic acid bacteria produces alcohols, acids, and esters (such as 2-phenylethanol, ethyl acetate, and methyl phenylacetate), which function as biomarkers of proper mucilage management and a balanced initial fermentation. In drying, the evolution of aldehydes derived from lipid oxidation and the retention of aromatic esters provide insights into dehydration kinetics and the stability of green coffee against oxidation. Finally, during roasting, volatile pyrazines, furans, thiols, and phenols integrate the entire postharvest history of the bean and enable inferences about roast degree, thermal overexposure, and final aroma development. Overall, the volatile biomarkers described here provide a robust chemical basis for objective monitoring of the postharvest process and the differentiation of coffee lots, although further studies are needed to define critical ranges by origin and processing system, standardize analytical methodologies, and quantitatively link these compounds to commercial quality parameters. Full article

Fermentation with various microorganisms modifies the quality of coffee. In animal-digested coffee, enzymatic activity also affects coffee characteristics. However, limited information is available on in vitro coffee modification employing both mechanisms simultaneously in controlled conditions. In this study, robusta green beans were modified with selected bacterial species (Bacillus subtilis, Gluconobacter sp., Lactiplantibacillus plantarum) and pepsin, which was introduced at the soaking or fermentation stage. The characteristics of green and roasted coffee were analyzed, including the amount of basic aroma precursors, antioxidant activity, acrylamide concentration and volatile organic compound (VOC) content. The number of bacterial cells increased by 1.95–2.64 logCFU/mL during the modification process; pepsin addition did not affect their growth significantly. The use of acid-producing bacteria (APB) resulted in higher consumption of sucrose but also in greater retention of bioactive compounds and higher antioxidant activity. The acrylamide content in fermented and roasted beans was below 10 μg/100 g dry matter; the lowest values were reported after modification with L. plantarum. The combination of tested bacterial and enzymatic processes changed the content and composition of VOCs. Further research should focus on sensory attributes as the result of the combined modification process. Full article

Microbial volatile organic compounds (VOCs) mediate rhizosphere plant-microbe interactions, yet their integrated effects on plant microbiome assembly and host transcriptional regulation remain unresolved. Here we address this gap by investigating how two common VOCs, acetoin (AC) and 2,3-butanediol (BD), influence growth, rhizosphere communities, and root gene expression in the medicinal plant Pseudostellaria heterophylla using a split-pot system. Bacterial and fungal communities were monitored across three developmental stages via amplicon sequencing, alongside root transcriptome profiling during tuber enlargement. Contrasting with widely reported growth-promoting effects of microbial VOCs, both compounds significantly reduced tuber number and biomass. Bacterial communities remained taxonomically stable, shaped primarily by species replacement, with modest VOC responses but clear shifts across developmental stages. Fungal communities exhibited marked compositional restructuring and greater treatment sensitivity, particularly under BD. Neutral community modeling indicated predominantly stochastic bacterial assembly, while fungal assembly—especially under BD—showed stronger influence of deterministic processes. BD associated with broader transcriptional reprogramming than AC, including downregulation of photosynthesis, specialized metabolism, and defense pathways. Cross-omics network analysis revealed discriminant genera (e.g., Granulicella, Harposporium) that correlated strongly with host genes involved in stress response, development, and epigenetic regulation, with fungal taxa showing tighter associations with host expression than bacteria. Together, these findings establish a mechanistic framework for how microbial VOCs shape rhizosphere communities and host responses, with implications for microbiome-based strategies in medicinal plant cultivation. Full article

Environmental health and biosecurity in pig farms and surroundings are increasingly threatened by pathogenic bacteria carried by fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM_2.5) in enclosed piggeries. However, limited attention has been given to these pathogens and their association with the respiratory microbiome of pigs. Using high-throughput sequencing, we investigated the overall and pathogenic bacterial communities attached to PM_2.5 in pig houses, as well as those in the upper (URT) and lower respiratory tracts (LRT) of healthy fattening pigs. Concentrations of PM_2.5, particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀), ammonia (NH₃), total volatile organic compounds (TVOCs), and hydrogen sulfide (H₂S) were significantly higher inside the piggery than in the surrounding environment. The composition of PM_2.5-associated bacteria varied with sampling height and showed greater similarity to the microbiota of the URT, particularly the oropharynx, than to that of the LRT. Additionally, 140 core potential bacterial pathogens were identified via Venn analysis in both PM_2.5 and respiratory tracts. Co-occurrence network analysis and community assembly patterns revealed that microbial communities in PM_2.5 and the respiratory tract exhibit distinct interaction and assembly characteristics. These findings highlight the potential role of PM_2.5 as a vector for respiratory pathogens and underscore the importance of air quality management in pig farming to safeguard environmental health. Full article

This study aimed to quantitatively determine the composition of 25 essential oils (EOs) using gas chromatography–mass spectrometry (GC-MS) to assess their minimum inhibitory concentrations (MICs) against selected rumen microorganisms and to confirm their effects in in vitro tests on volatile fatty acid (VFA) formation. GC-MS analysis identified over 80 compounds across the tested oils. The MICs were determined for Butyrivibrio fibrisolvens, Prevotella albensis, Lactobacillus delbrueckii ssp. lactis, and Streptococcus bovis, revealing diverse sensitivities. The rumen bacteria’s sensitivity to essential oils varied by strain, with some microorganisms inhibited at low concentrations while others required higher doses, highlighting the potential for targeted modulation of the rumen microbiota. Amyris balsamifera and Zingiber officinale demonstrated strong inhibitory effects at low concentrations and simultaneously enhanced VFA production. In contrast, Lavandula officinalis showed inhibitory effects on VFAs. Amyris balsamifera and L. officinalis also exhibited methane reduction. These findings demonstrate that selected essential oils can modulate rumen microbiota and fermentation by either inhibiting or stimulating specific bacterial groups, highlighting their potential as natural modulators to improve rumen function and animal health. Full article

Diacetyl has been a known key volatile compound for almost one century, a metabolite naturally produced by different microorganisms during fermentation processes, with traditional applications in food products preparations. Since its discovery, diacetyl has been recognized and actively explored regarding its buttery aroma, which is beneficial for a variety of fermented dairy foods. It is primarily synthesized by lactic acid bacteria (LAB) and other microbial groups through citrate metabolism, a pathway that is strain-dependent and strongly influenced by environmental conditions. Moreover, beyond its sensory relevance, diacetyl has attracted increasing scientific attention because of its antimicrobial activity, including synergistic interactions with bacteriocins and other microbial metabolites, which may enhance food preservation and biotechnological strategies. In contrast, its presence merits attention and needs to be carefully monitored in alcoholic beverages such as beer and wine, where excessive accumulation may compromise product quality. Some studies suggested that diacetyl may have negative health influences and presents safety concerns, as inhalation exposure was associated with pulmonary toxicity and occupational diseases, and was even suggested as one of the risk factors in electronic cigarettes. Emerging studies suggest that diacetyl may exhibit pharmacological potential, including antioxidant, antifungal, and even neuroprotective properties, although research is still in early stages and merits deeper scientific evaluation. Considering its dual nature, beneficial and harmful, this review provides an overview of diacetyl’s properties, safety considerations, and promising applications in biotechnology, biomedicine, and fermented food systems, but with a focus on potential industrial and health hazards. In the current review, we have presented evidence for diacetyl’s beneficial properties and discussed its hazards. Full article