Search Results (2,481)

Efficient utilization of lignocellulosic biomass by the rumen microbiome is critical for improving feed efficiency in ruminants, yet the development of stable, functionally specialized microbial consortia remains limited. This study aimed to assemble substrate-adapted rumen microbial consortia using an ecology-guided enrichment approach. Rumen fluid collected from cannulated Angus × Hereford heifers was sequentially enriched over 10 generations on four substrates with distinct cell wall characteristics: alfalfa, barley straw, carboxymethyl cellulose (CMC), and xylan. Fermentation parameters, including gas production and volatile fatty acids (VFAs), and bacterial community dynamics were analyzed, and selected consortia (alfalfa and xylan) were evaluated for stability following one month of cryopreservation. Across enrichments, total VFA concentrations declined (e.g., xylan: 109.8 mM (G0) to 56.37 mM (G10)), accompanied by reduced gas production and decreased alpha diversity, indicating substrate-driven selection. Distinct functional profiles emerged, including increased propionate in alfalfa consortia, higher acetate in barley straw, lactate–propionate cross-feeding with CMC, and caproate production (6.3 mM at G10) in xylan enrichments associated with Caproiciproducens and Megasphaera. Cryopreserved consortia retained core community structure and fermentation characteristics upon revival. These results demonstrate that substrate-driven enrichment can generate stable, functionally specialized rumen consortia and provide a framework for developing ecologically compatible microbial communities with potential applications in improving rumen fermentation efficiency. Full article

This study investigated the effects of red grape pomace powder (GPP) on spontaneously fermented salamis produced from the meat of retired cows and young bulls of the Cinisara dairy breed. The use of GPP and meat from these animal categories was motivated by the valorization of low-commercial-value agri-food resources and the enhancement of sustainable local production chains. Plate count analyses showed typical fermentation dynamics, with lactic acid bacteria (LAB), coagulase-negative staphylococci, and yeasts reaching approximately 7 log CFU/g, and confirmed the absence of major foodborne pathogens. Illumina sequencing further characterized the bacterial community, identifying Latilactobacillus as the dominant genus at the end of ripening, with relative abundance (RA) of up to 65% in GPP-enriched trials. Physicochemical analyses showed progressive changes during ripening, including weight loss, pH decrease, color development, and increased proteolysis. GPP supplementation contributed to the stabilization of a*, chroma, and hue values, while reducing lightness during ripening. Oxidative stability measurements showed that GPP derived polyphenols effectively limited oxidative reactions, especially secondary lipid oxidation. GPP also modulated the volatile profile by increasing ester formation and introducing plant-derived compounds. Sensory evaluation revealed higher color intensity and aroma in enriched salamis, along with higher bitterness and lower structural homogeneity, especially in those produced from retired cows. Consumer surveys conducted in two retail settings indicated strong interest in this innovation, with over 80% of respondents willing to pay a 10–20% price premium. Overall, GPP emerges as a promising functional ingredient for enhancing, diversifying, and valorizing fermented salamis produced from dairy cattle meat, supporting both product innovation and sustainability-oriented strategies. Full article

This study evaluated the effects of replacing whole-crop maize silage with varying proportions of Pennisetum giganteum silage on rumen fermentation, microbial composition, and metabolic function in beef cattle. A single-factor completely randomized design was employed using 50 healthy crossbred Simmental cattle aged 11–12 months (average body weight: 251.08 ± 51.54 kg). Animals were randomly assigned to five groups, with 10 replicates per group and one animal per replicate. Diets contained 0% (Group A), 25% (Group B), 50% (Group C), 75% (Group D), or 100% (Group E) Pennisetum giganteum silage replacing whole-crop maize silage over a 67-day feeding period, including a 7-day adaptation phase. Rumen fluid samples were collected via rumen catheter at the end of the trial to assess bacterial diversity and functional characteristics. Increasing the proportion of Pennisetum giganteum silage resulted in quadratic changes in volatile fatty acids (VFAs) and propionate (PA) concentrations (p < 0.05), while ammonia nitrogen (NH₃-N) increased linearly (p < 0.05). No significant differences were observed in α- or β-diversity among groups (p > 0.05). Group C exhibited significantly higher relative abundances of Verrucomicrobiota and Prevotellaceae_UCG_003 compared with the other groups (p < 0.05). At the phylum level, Proteobacteria increased linearly, whereas Spirochaetota decreased linearly; at the genus level, Treponema decreased linearly (p < 0.05). LEfSe analysis indicated enrichment of g__Prevotellaceae_UCG_003 and o__WCHB1_41 in Group C, while the relative abundances of f__Enterobacteriaceae and g__Citrobacter were elevated in Group E. Under the conditions of this study, replacing 50% of whole-crop maize silage with Pennisetum giganteum silage enhanced rumen fermentation efficiency and modulated key microbial populations in beef cattle. Full article

This study investigated the effects of fermented Chinese chive (FCC) juice supplementation on growth performance, blood parameters, meat quality, and fresh meat volatile compounds in Small-Tailed Han sheep. Sixty sheep were randomly assigned to a control group (CG; basal diet) or an FCC juice treatment group (TG; basal diet supplemented with 1.0 mL/kg feed offered on an as-fed basis), with three pens per treatment and 10 sheep per pen. FCC juice significantly increased average weight gain (AWG) and average daily gain (ADG) (p < 0.05), whereas carcass traits were not significantly affected (p > 0.05). Most meat quality traits, antioxidant indices, and serum biochemical parameters were unchanged, although serum glucose (GLU) and cholesterol (CHO) decreased in the FCC juice treatment group (p < 0.05). GC × GC-TOF/MS analysis showed that FCC juice altered the volatile profile of fresh sheep meat. Compared with the control group, the FCC juice treatment group showed higher relative contents of aldehydes, ketones, and heterocyclic compounds, but lower contents of hydrocarbons and acids. Seventeen differential volatile compounds were identified using VIP > 1 and FDR-adjusted p < 0.05, with esters representing the major upregulated class. Based on the published odor descriptors of the identified volatile compounds, the FCC juice treatment group showed stronger green and apple-like aroma-associated characteristics. Overall, FCC juice showed a modest positive effect on growth performance and altered the volatile compound profile of fresh sheep meat; however, flavor-related findings should be regarded as preliminary because of the limited slaughter sample size and the absence of direct sensory validation. Full article

In our preliminary work, a clam sauce prepared by fermentation with Aspergillus oryzae 3.042 (AO) exhibited desirable flavor and quality; however, the process was prolonged (exceeding 30 d), and a high salt concentration (6–15%) was necessary to prevent spoilage. Consequently, shortening production cycle and reducing salt content without compromising product quality became a new objective. Enzymatic hydrolysis has long been recognized as an efficient approach in seasoning production, with enzyme efficacy being a key competitive factor. Accordingly, an AO-derived aminopeptidase–protease complex (AOAP) was optimized and prepared as a preparatory step. In this study, AOAP was applied to hydrolyze clam meat to evaluate its potential for producing a seasoning base. A two-step enzymatic hydrolysis process was employed. In the first step, the highest hydrolysis degree (29.1%) was achieved using alkaline protease (AP). The resulting hydrolysate was subsequently subjected to secondary hydrolysis with AOAP, achieving a degree of hydrolysis as high as 49.8%. Sensory evaluation revealed a significant reduction in bitterness and enhancement of umami in the final hydrolysate, a finding corroborated by electronic tongue analysis. Further characterization via LC-MS and amino acid (aa) analysis showed that a substantial number of bitter and umami peptides were released following AP treatment; however, the number of these peptides was markedly reduced after a subsequent AOAP hydrolysis, with concurrent substantial changes in the peptide profile. In the two-step hydrolysate, umami peptides mostly contain 3–10 aa, whereas bitter peptides typically contain only 3–5 aa. The content of free aa increased from 369.17 mg/100 g in the control to 3026.25 mg/100 g in the two-step hydrolysate, half of which were bitter, indicating the debittering efficiency of AOAP. Electronic nose analysis revealed similar flavor profile and characteristic presence of nitrogen oxides in all hydrolysates. GC-MS analysis further demonstrated that, after combined enzymatic hydrolysis, the short-chain aldehydes and ketones responsible for the fishy odor in the raw material almost completely disappeared, while long-chain aldehydes with pleasant aromas were generated. These findings suggest that the secondary hydrolysis step using AOAP can effectively improve the overall flavor profile of the clam hydrolysate, which may support its potential applicability in seasoning production, though further optimization and scale-up validation are needed. Full article

The effects of direct inoculation of compound culture starter (Lactiplantibacillus plantarum and Saccharomyces cerevisiae) on the color, texture, and flavor qualities of fermented pork liver, sausage, and jerky were investigated. The results showed that inoculation with Lactiplantibacillus plantarum and Saccharomyces cerevisiae could significantly increase the lightness value (L*) and chroma value (C*) values of meat products and promote the color development of products. Meanwhile, it can also improve the tenderness of the products. The post-inoculation fermentation process enhanced the diversity and concentration of flavor compounds, improving the overall flavor of the product, and a total of 11 characteristic flavor compounds were identified. Inoculated fermentation reduced the levels of pentanal and methanethiol, which were unpleasant odor components in pork liver. In addition, inoculation fermentation could reduce the concentration of nonanal, which contributes to rancid fat odor in jerky. Inoculated fermentation enriched the flavor profile of meat products through the dual effects of “removing gamey flavor and enhancing aroma”. The results also showed that, after inoculation, the umami taste of meat products was enhanced, and bitter and sour tastes were inhibited. In conclusion, Lactiplantibacillus plantarum and Saccharomyces cerevisiae could serve as an excellent culture starter for industrial production, providing a feasible path for green and healthy meat processing. Full article

In this study, an acid-tolerant and high-fermentation performance strain of Kazachstania humilis (K. humilis 3-8) was screened from sourdough isolates and co-cultured with Fructilactobacillus sanfranciscensis (F. sanfranciscensis 5) to prepare liquid sourdough, which was further applied in mantou production. The effects on physicochemical properties, nutritional characteristics, and microbial interactions were investigated. K. humilis 3-8 exhibited strong gas production and acid tolerance, achieving a dough volume increase of 72.19% after 3 h fermentation. In co-culture, F. sanfranciscensis 5 maintained stable growth, while its metabolites significantly inhibited the growth of K. humilis 3-8 during mid-fermentation. The co-fermented dough showed decreased pH and increased total titratable acidity. Metabolomic analysis indicated enhanced carbohydrate metabolism and amino acid metabolism, suggesting carbon–nitrogen metabolic interactions between the two strains. When applied to Mantou production, the optimized co-culture system substantially enhanced product functionality, increasing resistant starch content by 76.7% (from 23.02% to 40.68%). Total phenolic content and antioxidant capacity were markedly enhanced. These findings elucidate complex microbial interactions governing sourdough ecosystems and establish a scientific foundation for the targeted improvement of traditional fermented cereal products through rational strain selection and process optimization. Full article

This study aimed to develop a high-value plant-based probiotic beverage via the co-fermentation of Lactobacillus plantarum (P8) and Bifidobacterium animalis subsp. lactis (V9) with almond hull homogenate as the fermentation substrate. Single-factor experiments combined with Box–Behnken response surface methodology were adopted to optimize the key fermentation parameters (compound bacteria ratio, inoculation amount, temperature, and fermentation time), with the probiotic proliferation multiple set as the response value. Furthermore, the physicochemical properties, active component contents, and antioxidant-related indicators of the fermented product were systematically determined and analyzed. The results showed that the optimal fermentation conditions were as follows: a P8:V9 ratio of 1:1, an inoculation amount of 0.1%, a fermentation temperature of 28 °C, and a fermentation time of 66 h. Under these optimal conditions, the viable probiotic count increased by 320-fold relative to the initial viable count, and the fermentation effectively induced the transformation of the bound bioactive components in the almond hull, with the free-flavonoid content increasing by 20.40% and the total polyphenol content decreasing by 6.16% in the fermented product, which reflected the dynamic conversion of nutrient components during the fermentation process. Meanwhile, the antioxidant capacity of the almond hull fermented product was significantly improved compared with the unfermented control. This study confirms the feasibility of almond hull as a suitable matrix for probiotic fermentation, and the findings provide a scientific basis for the development of plant-based synbiotic products and the high-value resource utilization of almond hull as an agricultural by-product. Full article

Green tea is highly popular due to its richness in polyphenols exhibiting broad bioactivities. Tea polyphenols, primarily catechins and flavonoids, demonstrate health benefits following biotransformation by the gut microbiota to overcome limited bioavailability. However, metabolites and interaction between green tea polyphenol and the gut microbiota remains to be fully elucidated. This study investigates the biotransformation of metabolites and interaction between human gut microbiota (HGM) and green tea extract (GTE) through in vitro anaerobic fermentation. Temporal bioactivity assessments demonstrated that fermentation-enhanced antioxidant capacity and inhibition potential of α-glucosidase, α-amylase and pancreatic lipase peak at 6 h, showing strong correlations with polyphenol and flavonoid biotransformation kinetics. Using the untargeted metabolomics approach, 55 characteristic differential compounds during the fermentation process in GTE were characterized, including 15 catechins, 29 flavonoids, five organic acids and six other phytochemicals. Furthermore, nine microbial-transformed metabolites derived from GTE flavonoids were identified and the corresponding metabolic pathways were proposed simultaneously. Analysis of 16S rRNA gene sequencing revealed that GTE significantly enhanced gut microbiota diversity and induced structural reorganization, specifically enriching genera such as Bacteroides, Bifidobacterium, Lactococcus and Enterococcus, which are likely involved in flavonoid biotransformation of GTE. Thus, the findings provide new insights for elucidating microbiota-mediated metabolites of green tea polyphenol, and their bidirectional interactions in the human gut. Full article

We aimed to develop kombucha-vinegar beverages inspired by switchel (a beverage that combines apple cider vinegar and ginger extract), using pecan shell aqueous extract (PSE) and green tea infusion (GTI) in the preparation of kombucha vinegar, and to assess its effects on physicochemical characteristics, antioxidant activity, and sensory acceptance. Combinations of PSE and GTI (100:0, 75:25, 50:50, 25:75, and 0:100) were tested as substrates to produce kombucha vinegar with an initial sugar concentration of 80 g/L. After, the initial sucrose concentration was tested (80 to 60 g/L) using two of the previous formulations (50% of PSE and 50% of GTI; 25% of PSE and 75% of GTI), that showed better results in antioxidant capacity and sensory characteristics, particularly bitterness, which was attributed to the addition of higher amounts of pecan nutshell extract (100 and 75%). The formulation with 60 g/L of sucrose and higher pecan shell extract (50%) was chosen, allowing a beverage with less sugar at the end of kombucha fermentation. An increase in antioxidant potential was observed during the fermentations, with this being a highlight of this study. Kombucha vinegar beverages inspired by switchel were developed (50% PSE and 50% GTI, 60 g/L of sucrose), with the use of ginger extract or juice fruits (apple, pineapple, or white grape), in order to make the beverage palatable to consumers. The samples without ginger showed the highest antioxidant capacity values. In the sensory evaluation using acceptability and the check all that apply method (CATA), the beverages without ginger showed acceptability ranging from 74.4% (addition of white grape juice) to 84.0% (addition of pineapple juice), being described as refreshing, healthy, and energizing. Full article

To protect wine authenticity and quality, two Sardinian red wines, Carignano del Sulcis and Cannonau di Sardegna, were characterized using an FT-IR and untargeted GC–MS integrated approach. FT-IR-derived oenological parameters, together with GC–MS profiles of polar low-molecular-weight metabolites, were subjected to multivariate statistical analysis. Compared with Cannonau, Carignano exhibited higher color intensity, greater density, and higher contents of glucose, lactic acid, and malic acid. Discriminant analysis of GC-MS data revealed that Carignano was characterized by uronic acids and arabitol, suggesting possible exposure to Botrytis. In contrast, Cannonau was characterized by 2,3 butanediol and ethyl-tartrate, indicating more pronounced yeast fermentative activity, consistent with the lower residual glucose content measured by FT-IR. Classification analysis demonstrated that the different wineries exert significant influence on the final characteristics of the wine. Overall, the findings demonstrated the effectiveness of this integrated analytical approach as a promising tool for wine authentication. Full article

Despite increasing interest in beer-derived umami peptides, their formation during lager beer fermentation and their potential roles in receptor recognition and sensory perception remain insufficiently understood. Therefore, this study combined peptidomics, in silico screening, receptor-oriented analysis, and sensory evaluation to investigate the dynamic changes in umami-related peptides throughout lager beer fermentation and to explore their possible sensory relevance. Peptide profiles varied markedly across the fermentation process, indicating continuous proteolysis and dynamic restructuring of the peptide pool. From these profiles, candidate umami peptides were screened, and representative short peptides with plausible receptor-binding characteristics were selected for further evaluation. These peptides showed measurable taste activity and were mainly associated with modulation of the umami–bitterness–aftertaste dimension, whereas their effects on aroma and overall balance were limited. In addition, the abundance of umami-related peptides was positively associated with perceived umami intensity. Overall, the results suggest that fermentation-derived peptides may contribute to taste perception in lager beer and provide a basis for further studies on flavor-oriented brewing and process regulation. Full article

The brewing industry remains at the forefront of technological innovation, with growing interest in alternative yeasts. Saccharomyces cerevisiae var. boulardii, a well-established probiotic yeast, has attracted attention for its potential to produce probiotic-enriched beers, offering an option for moderate consumers seeking functional beverages. This mini-review brings together current research on the use of S. boulardii in craft brewing, focusing on fermentation performance, flavour and sensory characteristics, and potential health-related functions. While often regarded as a variant of S. cerevisiae, S. boulardii shows comparable or greater cell growth, increased acetic acid production at the expense of glycerol, and lower alcohol yield compared to S. cerevisiae. Despite these differences, beers brewed with S. boulardii exhibit similar volatile compound profiles and sensory characteristics to those produced with S. cerevisiae. In terms of health-related attributes, S. boulardii-fermented beers show higher antioxidant activity, the presence of malto-oligosaccharides with prebiotic potential, and the ability of yeast to survive both storage and gastrointestinal transit. Strategies explored to optimise its brewing performance and customer acceptance include co-fermentation with S. cerevisiae, modified mashing protocols, and natural flavour additions. Overall, the available evidence supports S. boulardii as a promising yeast for developing probiotic-enriched beers. Further research is needed to validate current findings at commercial scales, investigate host–microbiome interactions following beer consumption and develop strategies that balance probiotic efficacy and desirable beer appearance over shelf life. The paper may assist brewers in making informed decisions about deploying S. boulardii, aligning consumer interest in functional beverages with the enjoyment of beer. Full article

Daqu is the core saccharifying and fermenting agent in Baijiu production and a pivotal factor in flavor formation. Challenges that often hinder traditional strong-flavor Daqu brewing include low enzymatic activity and insufficient aroma. Therefore, we have developed a novel Daqu brewing system. Furthermore, we investigated the differences in flavor profiles between traditional and novel Daqu by performing headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). We comparatively analyzed the microbial communities, metabolic functions, and flavor compositions in the two Daqu types via absolute quantitative metagenomics. Functional microorganisms were significantly enriched in the novel Daqu, which exhibited enhanced carbohydrate metabolism and a highly robust acidic environment owing to the fostering of core functional genera such as Aspergillus, Saccharomyces, and Pediococcus. This significantly increased the aldehyde and organic acid levels, which resulted in pronounced aldehydic and acidic sensory characteristics. Carbohydrate-Active EnZyme (CAZy) profiling confirmed the significantly elevated abundance of glycoside hydrolases (GHs) and glycosyltransferases (GTs) in novel Daqu, which improved starch bioconversion and synthesis of flavor precursors. Thus, this study shows that novel Daqu promotes ethanol accumulation and the synthesis of flavor compounds like acetals by strengthening the core microbiota and metabolic networks. These findings provide a theoretical foundation for enriching the aromatic complexity of Baijiu. Full article

The rumen microbiota plays a key role in nutrient fermentation and short-chain fatty acid (SCFA) production in ruminants. However, the impacts of different feeding regimes on rumen microbial composition, functional potential, and metabolic outputs remain unclear. In this study, rumen fluid samples were collected from 12 Longdong goats (Capra hircus), which were divided into four groups based on feeding regime and coat color: housed white goats (n = 3), housed black goats (n = 3), grazing white goats (n = 3), and grazing black goats (n = 3). Samples were analyzed using high-throughput sequencing combined with functional annotation (KEGG and CAZy) and targeted SCFA profiling. Distinct differences in microbial community composition were observed primarily between feeding regimes, with enrichment of taxa related to carbohydrate degradation and fermentation. Functional analyses revealed significant shifts in metabolic pathways, particularly those associated with carbohydrate metabolism, energy production, and glycan biosynthesis. Several glycoside hydrolase and glycosyltransferase families showed differential abundances across groups. Consistently, SCFA concentrations varied significantly among feeding regimes. Correlation analyses further demonstrated strong associations between key microbial taxa, functional pathways, and specific SCFAs. Overall, these results indicate that feeding regime, rather than coat color, plays a dominant role in shaping rumen microbial structure, functional capacity, and fermentation characteristics, providing insights into microbial mechanisms underlying rumen metabolism and informing feeding strategy optimization. Full article