Search Results (1,029)

Koji production is a critical process that determines the flavor and quality of the final soy sauce product. However, the complex mechanisms underlying microbial metabolism and the evolution of the physicochemical environment still require further analysis. This study focuses on three parallel koji rooms in an industrialized koji fermentation process. This work tracked the dynamics of physicochemical indices, volatile flavor compounds, and microbial communities over a full 40 h cycle. Data integration and correlation analysis elucidated the close linkage between the microbial community, the fermentation environment, and flavor formation. Koji moisture declined gradually, with faster losses at later fermentation stages. This physiological dehydration arose from microbial metabolic heat, forced aeration and structural loosening of koji, not simple physical evaporation. System pH displayed a typical U-shaped trend across fermentation. Values dropped early, most likely driven by accumulating organic acids, before rising from mid to late fermentation. This pH rebound was tentatively attributed to ammonia release from proteolytic breakdown, which may neutralize acidic compounds. These observations cast doubt on the conventional assumption that organic acid levels may be reliably estimated solely from pH measurements. Physicochemical analysis showed continuous accumulation of amino acid nitrogen (0.6–0.9 g/100 g) and total acidity throughout fermentation. By contrast, reducing sugar concentrations differed across individual koji rooms, presumably owing to divergent microbial adaptation in early fermentation. A total of 77 common compounds were identified, among which 13 key odor-active compounds with OAV ≥ 1, such as 4-vinylguaiacol and 3-methylbutyraldehyde, constitute the characteristic flavor profile of soy sauce starter culture. High-throughput sequencing uncovered a distinct ecological pattern: eukaryotic communities, dominated by Aspergillus oryzae, converged under controlled regulation. While prokaryotic communities differentiated dynamically, driven by spatial heterogeneity in the semi-open fermentation environment. Spearman correlation analysis further indicated potential functional partitioning: high-abundance taxa (e.g., Aspergillus oryzae, Weissella) were predominantly associated with macromolecular substrate degradation, whereas rare low-abundance taxa (e.g., Alternaria) displayed significant correlations with the biosynthesis of key characteristic flavor compounds. This study clarifies the synergistic regulatory mechanisms linking physicochemical conditions, microbial metabolism, and flavor precursor formation during industrial koji production. The findings establish a scientific foundation for optimizing process parameters and achieving standardized quality control in soy sauce manufacturing. Full article

Adolescence is a developmental stage marked by dynamic interactions between diet, the gut microbiome and endocrine maturation, creating a physiological environment in which early metabolic disturbances can rapidly translate into long-term cardiovascular vulnerability. This narrative review summarises the latest research on the diet–microbiome–hormone axis in adolescents, focusing on the metabolic pathways through which microbial metabolites influence host physiology. Short-chain fatty acids (SCFAs), microbially transformed bile acids and postbiotic signalling molecules regulate enteroendocrine communication, insulin sensitivity, vascular function and inflammatory tone, thereby linking dietary exposures to early cardiometabolic alterations. Dysbiosis, driven by ultra-processed dietary patterns, low fibre intake and reduced microbial diversity, promotes metabolic endotoxemia, neuroendocrine imbalance and endothelial impairment, all of which are recognised as early indicators of cardiovascular disease. A distinctive contribution of this review is the integration of PF into the adolescent cardiometabolic framework. This emerging biotechnological process enables the controlled production of structurally defined bioactive compounds, including angiotensin-converting enzyme (ACE) inhibitory peptides, targeted prebiotic oligosaccharides, fermentable substrates that promote SCFA formation, microbially derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), phytosterols and purified postbiotics. These compounds modulate several regulatory pathways, such as the renin–angiotensin–aldosterone system, lipid and bile acid metabolism, gut barrier stability, inflammatory signalling and endocrine axes involving glucagon-like peptide-1 (GLP-1), peptide YY (PYY), leptin, insulin sensitivity and growth hormone/insulin-like growth factor-1 (GH/IGF-1) dynamics. By situating precision fermentation within the broader context of adolescent metabolic susceptibility, this review highlights its potential to support microbiome resilience, stabilise hormonal regulation and mitigate early cardiovascular risk. However, further adolescent-specific clinical trials and long-term safety assessments are required to translate these advances into effective public health strategies. Full article

Methane production from Brosimum alicastrum seed coat was evaluated using a logistic model through three alkaline concentrations (0.19 M, 0.26 M, and 0.28 M) and three enzymatic activity levels (3000 U mL${}^{-1}$, 5000 U mL${}^{-1}$, and 7000 U mL${}^{-1}$) as pretreatments. Laccase was produced through submerged fermentation using T. hirsuta Bm-2 fungi, while NaOH served as the alkaline agent. Enzymatic pretreatment resulted in the highest specific CH${}_4$ yield (427.43 ± 2.28 mL CH${}_4$/g VS${}_{added}$), surpassing both alkaline pretreatment (235.61 ± 9.19 mL CH${}_4$/g VS${}_{added}$) and the control (102.54 ± 5.55 mL CH${}_4$/g VS${}_{added}$). Kinetic analysis of CH${}_4$ production indicated that cumulative CH${}_4$ production reached its stationary phase within 30 days of digestion. Moreover, enzymatic pretreatment exhibited the highest CH${}_4$ formation rate (0.15–0.16 h${}^{-1}$), except for the control, which had a slightly higher rate (0.22 h${}^{-1}$). The kinetic analysis revealed that the enzymatic pretreatment significantly improved the hydrolysis stage of Ramon’s seed coat, promoting higher cumulative CH${}_4$ production and leading to an increased specific CH${}_4$ yield. Full article

This investigation evaluated temporal variations in metabolic fingerprints, sensory properties, and functional traits of Aronia melanocarpa syrup throughout the fermentation stage followed by an additional 90-day preservation interval. Findings indicated that microbial transformation notably increased the cumulative polyphenolic levels, overall flavonoid concentrations, and DPPH free radical quenching efficiencies of the preparation, which stayed consistent over this duration. Non-targeted metabolomics screening recognized a combined 1918 chemical signatures, whereby phenylpropanoids, fatty acids, and terpenes represented critical components. A total of 1591 distinct metabolites were identified, demonstrating substantial accumulation inside the flavonoid synthesis and pyruvate catabolic pathways. Furthermore, 355 volatile substances were characterized, with aldehydes and esters acting as vital elements providing honey-scented and fragrant tastes. The cooperative impacts of brewing and aging improved the nutritive and gustatory merits of Aronia melanocarpa syrup, providing a theoretical framework for developing superior fermented commodities. Full article

Pear fruits host diverse microbial communities that influence postharvest quality, spontaneous fermentation, and susceptibility to microbial contamination. This study characterizes the fungal communities associated with naturally fallen overripe pears (Pyrus communis) using ITS2 amplicon sequencing combined with culture-dependent approaches. The fungal community exhibited low diversity and was dominated by Ascomycota (99%), primarily Saccharomycetes (91.8%), with Hanseniaspora, Aureobasidium, and Microcyclospora representing more than 90% of the total microbial community. Culture-dependent isolation confirmed Hanseniaspora uvarum as the dominant yeast species (~89%), followed by Metschnikowia spp. and Pichia spp. Pairwise co-culture assays, quantified using the Relative Interaction Index, demonstrated predominantly competitive interactions, with fast-growing H. uvarum exerting suppressive effects on slower-growing species. Among the isolated yeasts, Metschnikowia fructicola exhibited antibacterial activity against all tested bacteria Staphylococcus aureus, Listeria innocua and Salmonella typhimurium. The strongest antibacterial activity was exerted against the foodborne pathogen S. aureus. In a pear juice model system, co-cultivation with M. fructicola resulted in the elimination of S. aureus within four days, while yeast viability was maintained. These findings observe the fermentative yeasts distributed in overripe pears and demonstrate the potential of M. fructicola to inhibit bacterial growth under controlled conditions. The results provide a preliminary basis for further studies on fungal succession, yeast interactions, and the biocontrol potential of pear-associated yeasts. For broader ecological conclusions, larger-scale studies across locations, seasons, cultivars, and decay stages are required. Full article

Livestock production is a major source of agricultural methane (CH₄) and nitrous oxide (N₂O), making the synergistic mitigation of these two gases essential for meeting climate targets. Based on the EDGAR emission database from 2000 to 2024, this study employs international comparisons, spatial analysis, and STIRPAT-based scenario projections to characterize emissions from China’s animal husbandry and explore pathways for synergistic mitigation. The results reveal that China’s livestock CH₄ emissions exhibited a trend of early-stage fluctuation followed by a late-stage rebound, while N₂O emissions fluctuated sharply. The two gases are strongly synergistic yet driven by distinct mechanisms. China accounts for the largest share of global emissions and exhibits a distinctive emission structure—with comparable contributions from enteric fermentation and rice paddies—setting it apart from both pasture-based and intensive developed countries. High-emission areas are becoming increasingly concentrated in northern production regions. Under the baseline scenario, CH₄ and N₂O emissions are projected to peak in 2032 and 2030, respectively; under an ultra-low-carbon scenario, both gases peak around 2029, at substantially lower levels. Achieving synergistic mitigation calls for a regionally differentiated framework that combines top-down governance with bottom-up participation from farmers, integrating enteric fermentation control with optimized manure management to support a low-carbon transition. Full article

This study compared a self-induced anaerobic fermented product (SIAFP), prepared with Bacillus subtilis M6 and Lactiplantibacillus plantarum R101, with dry-form (DTFP) and wet-form (WTFP) two-stage fermented products in broilers. Three trials were conducted: Trial 1 evaluated the physicochemical properties and growth performance; Trial 2 assessed nutrient composition and apparent total tract digestibility; and Trial 3 determined the optimal dietary inclusion level of SIAFP. In Trial 1, SIAFP exhibited the lowest pH and the highest Lactiplantibacillus-like counts (p < 0.05), and all fermented product groups showed higher body weight gain and performance efficiency factor compared to the unfermented control (p < 0.05). In Trial 2, SIAFP contained higher crude protein and total amino acid contents, concomitant with improved hemicellulose digestibility (p < 0.05). In Trial 3, incremental dietary inclusion of SIAFP (0–3.75%) exerted linear or quadratic effects on body weight gain and feed conversion ratio (p < 0.05), with optimal performance observed within the range of 1.25–2.5%. In conclusion, SIAFP showed comparable growth-promoting effects to DTFP and WTFP, suggesting its potential as a practical alternative fermented feed product. Dietary inclusion at 1.25–2.5% effectively enhanced growth performance, which may be attributed to improved nutrient composition and digestibility in broilers. Full article

Variations in sweetness and bitterness among Madhuca longifolia flowers strongly influence their processing value and market acceptance, yet the chemo-diversity underlying these traits remains poorly characterized. This study aimed to unravel accession- and stage-specific differences by integrating physico-biochemical, elemental, and metabolic profiling across thirteen accessions (BM-1 to BM-13) from BUAT, Banda. Sensory and textural evaluations revealed wide diversity, with BM-5 displaying superior sweetness and aroma, whereas BM-6, BM-7, and BM-10 were differentiated by firmness, elasticity, and gumminess. Biochemical analyses across flower development showed that BM-5 consistently maintained higher sugars and β-carotene, while BM-1 exhibited marked reductions in sugars and total phenolics content; meanwhile, antioxidant activity increased with maturity, with BM-5 remaining the most stable. ICP-MS elemental analysis confirmed BM-5 as mineral-rich compared with lower-performing accessions. GC-MS metabolomic profiling of contrasting accessions (BM-1 and BM-5) across stages identified 303 volatile and semi-volatile metabolites, and multivariate analyses (PCA, VIP, volcano plots, pathway enrichment) revealed distinct stage- and accession-dependent patterns. Mature BM-5 was enriched in fermentation- and aroma-related metabolites such as melibiose, furfural, 5-HMF, and furaneol, whereas BM-1 accumulated defense-linked compounds including catechol, benzyl nitrile, and maltol. Overall, the integrated chemo-diversity landscape identifies BM-5 as a superior accession with high processing potential and value-addition prospects. Full article

The suckling phase is the critical window for rumen functional maturation, yet amino-acid-based interventions tailored to this stage remain scarce. L-citrulline (L-cit) bypasses hepatic first-pass metabolism, is converted to L-arginine peripherally, and resists ruminal microbial degradation, making it a candidate functional additive for early-life ruminants. This study evaluated whether dietary L-cit at 2 g·lamb⁻¹·d⁻¹ would improve rumen development and metabolic function in suckling Hu lambs. Twenty male Hu lambs were randomly assigned to a control (CON) or L-cit group (n = 10/group) and reared for 45 d (3 d adaptation + 42 d treatment). Growth and starter intake were assessed in all lambs; six lambs per group (n = 6) were subsequently slaughtered for rumen morphometry, gas chromatography–flame ionization detection (GC-FID) volatile fatty acid (VFA) quantification, 16S rRNA gene sequencing, and liquid chromatography–mass spectrometry (LC-MS) untargeted metabolomics. L-cit increased average daily starter intake by 25.96% (p = 0.036) and produced a 20.00% numerical but non-significant increase in average daily gain (ADG) (p = 0.203; Cohen’s d = 0.58). Rumen weight, volume, and papillary length, width, density, and epithelial thickness were all elevated (p < 0.05), whereas muscular thickness was unaffected (p = 0.162). Total VFA, acetate, propionate (+37.64%, p < 0.001), and butyrate were higher in the L-cit group; the molar proportion of propionate rose from 21.41% to 24.75%, and the acetate-to-propionate ratio declined from 2.90 to 2.44 (p = 0.005). Microbial richness (Chao1, Observed species) increased without altered evenness, and linear discriminant analysis effect size (LEfSe) identified L-cit-driven enrichment of propionate-generating and fiber-degrading genera, including Prevotellaceae_UCG-004, Ruminobacter, and the NK4A214_group. Of 539 differential metabolites (147 of which were annotated to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database), KEGG enrichment highlighted linoleic acid metabolism and purine metabolism as the biologically interpretable targets. Microbiota–metabolite correlations linked L-cit-enriched genera to up-regulated metabolites such as adenine. Dietary L-cit at 2 g·lamb⁻¹·d⁻¹ enhances starter intake, promotes rumen epithelial development, promotes a shift toward enhanced propiogenic fermentation within an acetate-dominant profile, and remodels the microbiota–metabolome axis, supporting its application as a functional additive during the suckling phase of ruminants. Because epithelial barrier integrity, oxidative stress, and inflammatory markers were not directly measured, these findings should be interpreted as morphological and association-based evidence, and further functional validation is required. Full article

This study investigated how three chili pepper varieties (Huanggong, millet, and long slender) affect fermentation dynamics, flavor formation, and microbial succession in spontaneously fermented chopped chili. Physicochemical analyses, sensory evaluation, GC–MS, electronic tongue analysis, and high-throughput sequencing were employed to characterize quality attributes, volatile flavor profiles, and microbial structures during the process. The results demonstrated that chili pepper variety significantly influenced fermentation behavior (pH range: 4.07–4.26; total acidity: 5.68–7.69 g/kg) and quality. Distinct differences were observed in acidification patterns, substrate utilization, sensory characteristics, and optimal fermentation stages Volatile flavor analysis revealed that chopped chili peppers produced from different varieties exhibited differentiated aroma profiles while sharing a common flavor framework composed of several key aroma-active compounds. Microbial community analysis indicated that the chili pepper variety drove distinct microbial succession patterns during the process, and dominant microbial groups showed significant correlations with the formation of specific flavor compounds. Overall, these findings demonstrate that chili pepper variety regulates flavor and quality formation in chopped chili peppers by modulating microbial community structure and metabolic activity, providing a scientific basis for raw material selection and targeted flavor control in fermented chili products. A total of 63–68 volatile compounds were identified across varieties, with OAV > 1 for 11–24 compounds. Three biological replicates were analyzed per time point. Full article

Fresh cowpeas have a limited shelf life at room temperature. Fermentation of cowpeas not only preserves their nutritional value but also prolongs their shelf life. This study categorized cowpea fermentation processes into natural and inoculated methods, focusing on analyzing physicochemical indices, acid production, and bacterial diversity throughout the cowpea fermentation process. We compared the moisture, protein content, and vitamin C levels of cowpeas. The acidification process was monitored using pH, total acid, and nitrite contents as indicators. Illumina MiSeq sequencing was employed to analyze the bacterial communities in fermented cowpeas at different fermentation stages. The experimental results indicated that during fermentation, pH, total acid content, and nitrite content all changed significantly. Lactobacillus exhibited high dominance in both natural fermentation and inoculated fermentation processes. Moreover, under inoculated fermentation conditions, its population size was significantly greater than that in natural fermentation. Analysis of bacterial community composition revealed that microbial diversity tended to decrease with prolonged fermentation time in both natural and inoculated fermentation systems. The results demonstrate that inoculation fermentation can shorten the fermentation cycle, lower nitrite levels, and confirm that lactic acid bacteria are the dominant microbial genus in vegetable fermentation. Full article

Modern dairy production has greatly increased milk yield, but high productivity is often accompanied by greater metabolic pressure, particularly during the transition period. Ketosis, fatty liver, and subacute ruminal acidosis are major disorders that limit health, efficiency, and sustainability in high-yielding dairy ruminants. This review examines the rumen microbiota as a central biological interface linking diet, ruminal fermentation, epithelial function, hepatic metabolism, and inflammation. Under homeostatic conditions, the rumen microbiota supports lactation by converting dietary fibre, starch, and nitrogen into volatile fatty acids, microbial protein, and other metabolites required for gluconeogenesis, milk component synthesis, and epithelial maintenance. However, under excessive nutritional or physiological stress, especially high-concentrate feeding and periparturient negative energy balance, this system may shift toward dysbiosis, acid accumulation, lipopolysaccharide release, epithelial barrier impairment, and activation of gut–liver inflammatory pathways. These changes can contribute to the occurrence and interaction of subacute ruminal acidosis, ketosis, and fatty liver. We further summarize key factors affecting rumen microbial stability, including diet structure, host variation, physiological stage, environmental stress, feeding management, and ruminal epithelial volatile fatty acid absorption. Finally, microbiome-oriented strategies, such as gradual dietary transition, nutritional preconditioning, probiotics, postbiotics, functional metabolites, host metabolic support, and epithelial-targeted interventions, are discussed. Maintaining rumen microbial homeostasis should be regarded as a core principle for balancing high milk yield with long-term metabolic health. Future research should move beyond descriptive profiling toward causal validation of host–microbe interactions and the development of microbiome-based early-warning and individualized nutritional management systems. Full article

The flavor profile of Longmen rice vinegar directly influences consumer purchase intention, and understanding its variation during fermentation is crucial for final product quality control. In this study, the flavor dynamics during the fermentation of Longmen rice vinegar were systematically investigated. Sensory evaluation indicated that acidity increased significantly during the acetic acid fermentation stage, while alcoholic and fermented odors decreased continuously. Instrumental analysis identified 129 volatile compounds, predominantly esters, alcohols, and acids. Based on relative odor activity value (r-OAV) analysis, acetic acid, 3-methylbutyl acetate, 2,3-butanedione, benzeneacetaldehyde, phenethyl alcohol, ethyl acetate, 2-phenylethyl acetate, ethyl 4-methyl-pentanoate, 3-methyl-1-butanol, and 3-methylbutanal were determined to be the major contributors to the overall aroma. Orthogonal partial least-squares discriminant analysis (OPLS-DA) further screened 21 key differential compounds. Significant variations in organic acid and amino acid contents during fermentation were also observed. Correlation analysis revealed relationships between key aroma compounds and organic, as well as amino, acids. These findings establish a foundation for monitoring flavor dynamics during the fermentation of Longmen rice vinegar. Full article

This study investigated the stage-dependent effects of salt, nitrite, heat treatment, and water activity (aW) on physicochemical and microbiological parameters during fermented meat manufacture. Eight formulations representing a fractional subset of a 2 × 2 × 3 × 2 factorial design were evaluated across four processing stages (pre-fermentation, post-fermentation, post-heat treatment, and post-drying). A stage-resolved multivariate analysis of variance (MANOVA) framework was applied, followed by univariate testing with Benjamini–Hochberg false discovery rate (FDR) correction. Results demonstrated that hurdle effects were strongly stage dependent. Nitrite and its interaction with salt were associated with early stage microbial variation (η² ≤ 0.72), while heat treatment was the dominant factor influencing microbial reduction at the post-processing stage. Notably, short high-temperature heat treatments were most effective at microbial reduction, followed by longer lower-temperature heat treatments, with the intermediate treatment being the least effective, indicating that equivalent time–temperature combinations did not yield equivalent microbiological outcomes. At the final stage, salt and nitrite were associated with compositional, microbial, and quality-related parameters, while aW influenced product structure and concentration effects but was not retained as an independent factor in the multivariate model. These findings indicate that hurdle effects evolve throughout processing and should be considered within a dynamic, stage-specific framework. The results provide a basis for the development of integrated reformulation strategies to reduce salt and nitrite levels while maintaining microbial stability and product quality. Full article

The alcoholic fermentation of wine is a complex, multivariable chemical process. This study proposes a cognitive system for the dynamic control of the industrial wine fermentation process based on acoustic emission signals. The core of the system uses machine learning algorithms to perform perception tasks and predict density as a relevant chemical parameter for control and decision-making during the process. A hydrophone submerged in the fermentation tank is used to monitor the process. At the TRL4 stage we are currently at, measurements were taken at a winery in the Rioja Designation of Origin and were acquired and stored during the alcoholic fermentation process to be used as input data. Manual measurements collected by the winemaker throughout the fermentation process were used to train and validate the results. The performance of the machine learning model was measured using statistical metrics. The results of the experiments show a high correlation between the density calculated using the model and the densities measured by the winemaker. The proposed system is a valid and innovative tool for controlling a process as multivariable as alcoholic fermentation. The anticipatory nature of the acoustic signal with regard to the evolution of temperature in the process is used as the starting point for the new proposal. Its application helps to ensure stable fermentation by reducing the thermal stress on yeasts caused by the thermal shocks of current temperature control systems, improving process control in wineries and serving as a cognitive system for control and decision-making. Full article