Search Results (31)

Certain probiotic strains have been proposed to alleviate mental health conditions, such as anxiety and stress, by modulating the gut–microbiota–brain axis through the production of metabolites like gamma-aminobutyric acid (GABA). This study evaluated kefir-derived microbial strains for their GABA-producing capacity in mono- and co-culture systems using whey as the growth substrate. Based on the screening results, two microbial consortia were selected to develop fermented whey beverages with raspberry (FWF-R1 and FWF-R2). These beverages were characterized for their technological and functional properties over 21 days of refrigerated storage and following gastrointestinal digestion. Both formulations maintained stable acidity and showed a slight increase in viscosity during storage. The microbial counts remained above 8.5 log colony-forming units/mL, with high post-digestion viability, confirming their probiotic potential. The GABA levels increased progressively during storage, reaching 2.67 mM in FWF-R1 and 4.65 mM in FWF-R2, with recovery rates of 40–45% after digestion. The total phenolic content decreased moderately during storage but increased ~5-fold after digestion; the total anthocyanins declined by up to 70%. FWF-R2 achieved higher sensory acceptability and was preferred by 58% of consumers, emerging as the most promising formulation. These findings highlight the psychobiotic potential of these beverages and support the sustainable valorization of dairy and fruit by-products. Full article

Critical illness profoundly disrupts the gut microbiota leading to a state of dysbiosis characterized by reduced microbial diversity and overrepresentation of pathogenic taxa such as Enterobacteriaceae and Proteobacteria. This dysbiotic shift compromises gut barrier integrity and modulates immune responses, contributing to systemic inflammation and increasing susceptibility to nosocomial infections and multi-organ dysfunction. Nutritional strategies in the ICU significantly influence the composition and function of the gut microbiota. Enteral nutrition supports the maintenance of microbial diversity and gut mucosal health, whereas parenteral nutrition is associated with mucosal atrophy and further microbial imbalance. Emerging interventions, including the administration of probiotics, prebiotics, synbiotics, and fermented products like kefir, show promise in restoring microbial equilibrium and improving patient outcomes. This review presents current evidence on the alterations of the gut microbiota in critically ill patients, explores the systemic consequences of dysbiosis, and evaluates the impact of nutritional and microbiota-targeted therapies in improving patient outcomes. Full article

Background/Objectives: Lactobacillus kefiranofaciens HL1, isolated from kefir, exhibits antioxidant and anti-aging activities, defined here as improved cognitive function and reductions in oxidative stress and inflammatory markers. However, its poor milk viability limits application. This study developed a novel fermented milk by co-culturing HL1 with Lactococcus lactis subsp. cremoris APL015 (APL15) to enhance fermentation and health benefits. Methods: HL1 and APL15 were co-cultured to produce fermented milk (FM), and fermentation performance, microbial viability, texture, and syneresis were evaluated. A D-galactose-induced aging BALB/c mouse model was used to assess cognitive function, oxidative stress, inflammation, antioxidant enzyme activity, and gut microbiota after 8 weeks of oral administration. Results: FM reached pH 4.6 within 16 h, with high viable counts (~10⁹ CFU/mL) for both strains. HL1 viability and texture were maintained, with smooth consistency and low syneresis. In vivo, FM improved cognitive behavior (Y-maze, Morris water maze), reduced oxidative damage (MDA), lowered IL-1β and TNF-α, and enhanced brain SOD levels. FM-fed mice exhibited increased short-chain fatty acid producers, higher cecal butyrate, and reduced Clostridium perfringens. Conclusions: The co-cultured fermented milk effectively delivers HL1 and provides antioxidant, anti-inflammatory, and anti-aging effects in vivo, likely via gut–brain axis modulation. It shows promise as a functional food for healthy aging. Full article

This study investigated ten potential toxic metals (PTMs) in six milk and dairy product types and evaluated food safety (TDI, RDA), human exposure (EDI), non-carcinogenic risk (THQ, HI), and contamination levels (CF, PLI). Based on total PTM load, products ranked as: children’s milk > yogurt > protein milk > milk > ayran > kefir. Aluminum (Al) showed the highest average concentration in all products except ayran, where manganese (Mn) was dominant. Cadmium (Cd), mercury (Hg), and lead (Pb) were consistently at the lowest levels. Except for chromium (Cr) exposure from children’s milk, all average and maximum EDI values stayed below TDI and RDA thresholds. Children’s milk had the highest non-carcinogenic risk, while yogurt, kefir, milk, and ayran may also pose potential risks when maximum HI values are considered. Although CF values varied across products, PLI results showed all products had high levels of PTM contamination. Given the widespread consumption of dairy across all age groups, especially by sensitive populations like children, monitoring and controlling PTM levels is crucial alongside ensuring nutritional quality. Full article

This study analyzes the aromatic profiles of kiwi-based fermented beverages, inoculated with varying proportions of milk kefir grains and incubated under different shaking rates. The experiments were designed using response surface methodology and three consecutive batch cultures were performed under each experimental condition. At the end of each fermentation, the grains were separated from the beverage and reused as the inoculum for fermenting fresh kiwi juice in the subsequent batch. Based on the results, together with the previously determined microbiological and chemical characteristics, two beverages were identified as having broader aromatic profiles, lower contents of sugars, ethanol, and acids, and high counts of lactic acid bacteria (LAB) and yeasts (>10⁶ CFU/mL). These beverages were produced under relatively low agitation rates (38 and 86 rpm) and high inoculum proportions (4.33% and 4.68% w/v) during the second and third batch cultures, respectively. Over 28 days of refrigerated storage, the pH values of both beverages remained relatively stable, and the LAB counts consistently exceeded 10⁶ CFU/mL. Yeast counts, along with the production of ethanol, glycerol, lactic acid, and acetic acid, increased slightly over time. In contrast, the concentrations of citric acid, quinic acid, total sugars, and acetic acid bacteria declined by day 28. Full article

This study aimed to identify kiwi kefir-like beverages with high levels of viable probiotic cells and low levels of calories, acids, and alcohol. To achieve this, microbiological and chemical characterizations were conducted on beverages inoculated with varying amounts of kefir grains (GW) and incubated at different agitation speeds (A), following a second-order orthogonal factorial design. For each experimental condition, three 24-h batch cultures were performed using three successive passages of kefir grains. Higher GW levels promoted greater nutrient consumption and metabolite production. However, an intermediate GW (1.80 g) resulted in the highest growth of lactic acid bacteria (LAB), acetic acid bacteria (AAB), yeasts, and free biomass in the fermented medium. Optimal agitation levels also enhanced nutrient consumption, free biomass, and metabolite pro-duction. AAB and yeast counts increased with higher agitation speeds, while LAB counts de-creased. Three beverages, produced during the second (A = 86 rpm, GW = 2.81 g) and third (A = 38 rpm, GW = 2.60 g; A = 86 rpm, GW = 1.80 g) kefir grain passages, exhibited LAB and yeast counts above 10⁶; CFU/mL, along with low total sugar and ethanol concentrations. These beverages may be considered suitable as potentially probiotic, low-alcohol, and low-calorie functional drinks. Full article

The essential amino acid tryptophan yields a plethora of secondary metabolites with key roles in plants and animals. Its fate in different living organisms is crucial for their own health, and metabolic profiling is a valuable tool for investigating it. Among the various metabolites, those retaining the indole structure were examined for qualitative and quantitative profiling. Liquid chromatography coupled with a tandem mass spectrometry detector with an electrospray ionization source (HPLC-ESI-MS/MS), acquiring in multiple reaction monitoring (MRM) mode, was used to develop a selective and sensitive method for the simultaneous analysis of tryptophan and 10 indole structure-retaining metabolites of it. Satisfactory values were obtained for linearity (R² ≥ 0.99 for all compounds except two), sensitivity (LOD, within 6–31 ng/mL, and LOQ, within 17–94 ng/mL, where minimum and maximum values were relative to serotonin and 5-methoxytryptamin, respectively), reproducibility (interday and intraday precision and accuracy), and effect of the matrix (recovery and matrix effect). The method was then successfully applied to the analysis of different types of beverage, such as herbal products, like Eschscholzia californica and a sleep herbal tea marketed with added melatonin (consumed to reduce anxiety and improve sleep quality), and fermented beverages, like beer and kefir. High amounts of tryptophan (from 77 ng/mL in kefir to 26,974 ng/g in the sleep herbal tea) followed by lower contents of serotonin (from 29 ng/mL in kefir to 2207 ng/g in the sleep herbal tea), were found in all samples along with the serotonin pathway-related compounds 5-hydroxytryptophan and tryptamine. Melatonin was detected in the plant matrix Eschscholzia c. for the first time to our knowledge (446 ng/g) and in the fermented beverages (96 ng/mL in beer and 39 ng/mL in kefir), regardless of their vegetable or animal origin, along with the melatonin route metabolites 5-methoxytryptamine and tryptophan ethyl ester. The amount of melatonin in the sleep herbal tea (556,464 ng/g) was in strong agreement with the declared content. Suggested applications include the search for biomarkers in phytochemical characterization, mechanistic studies of tryptophan’s chemistry, valorization of foods, beverages, and tryptophan-rich agro-food by-products and waste for nutraceutical and pharmacological purposes. Full article

Kefir-based fermentation products exhibit antioxidant and anti-inflammatory effects against oxidative stress, inflammation, platelet activation and aggregation, and other related manifestations, thereby preventing the onset and development of several chronic diseases. Specifically, water kefir, a symbiotic culture of various microorganisms used for the production of several bio-functional fermented products, has been proposed for its health-promoting properties. Thus, water kefir grains and its apple pomace-based fermentation beverage were studied for bioactive amphiphilic and lipophilic lipid compounds with antioxidant, antithrombotic, and anti-inflammatory properties. Total lipids (TL) were extracted and further separated into their total amphiphilic (TAC) and total lipophilic content (TLC), in which the total phenolic and carotenoid contents (TPC and TCC, respectively) and the fatty acid content of the polar lipids (PL) were quantified, while the antioxidant activity of both TAC and TLC were assessed in vitro, by the ABTS, DPPH, and FRAP bioassays, along with the anti-inflammatory and antithrombotic activity of TAC against human platelet aggregation induced by the thrombo-inflammatory mediator, platelet-activating factor (PAF) or standard platelet agonists like ADP.ATR-FTIR spectra facilitated the detection of specific structural, functional groups of phenolic, flavonoid, and carotenoid antioxidants, while LC−MS analysis revealed the presence of specific anti-inflammatory and antithrombotic PL bioactives bearing unsaturated fatty acids in their structures, with favorable omega-6 (n-6)/omega-3 (n-3)polyunsaturated fatty acids (PUFA), which further support the findings that the most potent antioxidant, anti-inflammatory and antithrombotic bioactivities were observed in the TAC extracts, in both water kefir grains and beverage cases. The detection of such bioactive components in both the uncultured water kefir grains and in the cultured beverage further supports the contribution of water kefir microorganisms to the bioactivity and the bio-functionality of the final fermented product. Nevertheless, the extracts of the beverage showed much stronger antioxidant, anti-inflammatory, and antithrombotic activities, which further suggests that during the culture process for producing this beverage, not only was the presence of bioactive compounds produced by kefir microflora present, but biochemical alterations during fermentation of bioactive components derived from apple pomace also seemed to have taken place, contributing to the higher bio-functionality observed in the apple pomace—water kefir-based beverage, even when compared to the unfermented apple pomace. The overall findings support further studies on the use of water kefir and/or apple pomace as viable sources of antioxidant, anti-inflammatory, and antithrombotic amphiphilic bioactive compounds for the production of novel health-promoting bio-functional fermented products. Full article

The beneficial effect of milk kefir on respiratory heath has been previously demonstrated; however, water kefir and kefiran in the context of respiratory viral infections have not been investigated. Water kefir and kefiran could be alternatives to milk kefir for their application in persons with lactose intolerance or milk allergy and could be incorporated into vegan diets. Using mice models, this work demonstrated that the oral administration of water kefir or kefiran can modulate the respiratory Toll-like receptor (TLR3)-mediated innate antiviral immunity and improve the resistance to respiratory syncytial virus (RSV) infection. The treatment of mice with water kefir or kefiran for 6 days improved the production of interferons (IFN-β and IFN-γ) and antiviral factors (Mx2, OAS1, RNAseL, and IFITM3) in the respiratory tract after the activation of the TLR3 signaling pathway, differentially modulated the balance of pro- and anti-inflammatory cytokines, reduced RSV replication, and diminished lung tissue damage. Maintaining a proper balance between anti-inflammatory and pro-inflammatory mediators is vital for ensuring an effective and safe antiviral immune response, and the results of this work show that water kefir and kefiran would help to maintain that balance promoting a controlled inflammatory response that defends against infection while minimizing tissue damage. Full article

Chronic inflammatory bowel disorders (IBDs) are characterized by altered intestinal permeability, prompting inflammatory, oxidative stress, and immunological factors. Gut microbiota disorders impact brain function via the bidirectional gut–brain axis, influencing behavior through inflammatory cascades, oxidative stress, and neurotransmitter levels. This study highlights the potential effect of integrating lyophilized milk kefir alone and lyophilized milk kefir as solid carriers loaded with a self-nanoemulsifying self-nanosuspension (SNESNS) of licorice extract on an induced chronic IBD-like model in rats. Licorice-SNESNS was prepared by the homogenization of 30 mg of licorice extract in 1 g of the selected SNEDDS (30% Caraway oil, 60% Tween 20, and 10% propylene glycol (w/w)). Licorice-SNESNS was mixed with milk kefir and then freeze-dried. Dynamic TEM images and the bimodal particle size curve confirmed the formation of the biphasic nanosystems after dilution (nanoemulsion and nanosuspension). Daily oral administration of lyophilized milk kefir (100 mg/kg) loaded with SNESNS (10 mg/kg Caraway oil and 1 mg/kg licorice) restored normal body weight and intestinal mucosa while significantly reducing submucosal inflammatory cell infiltration in induced rats. Importantly, this treatment demonstrated superior efficacy compared to lyophilized milk kefir alone by leading to a more significant alleviation of neurotransmitter levels and improved memory functions, thereby addressing gut–brain axis disorders. Additionally, it normalized fecal microbiome constituents, inflammatory cytokine levels, and oxidative stress in examined tissues and serum. Moreover, daily administration of kefir-loaded SNESNS normalized the disease activity index, alleviated histopathological changes induced by IBD induction, and partially restored the normal gut microbiota. These alterations are associated with improved cognitive functions, attributed to the maintenance of normal neurotransmitter levels and the alleviation of triggered inflammatory factors and oxidative stress levels. Full article

Probiotics are “live microorganisms which, when administered in adequate amount, confer health benefits on the host”. They can be found in certain foods like yogurt and kefir and in dietary supplements. The introduction of bacterial derivatives has not only contributed to disease control but has also exhibited promising outcomes, such as improved survival rates, immune enhancement, and growth promotion effects. It is interesting to note that the efficacy of probiotics goes beyond the viability of the bacteria, giving rise to concepts like paraprobiotics, non-viable forms of probiotics, and postbiotics. Paraprobiotics offer various health benefits in children with intestinal dysbiosis, contributing to improved digestive health, immune function, and overall well-being. In this review, the potential of these therapeutic applications as alternatives to pharmacological agents for treating pediatric intestinal dysbiosis will be thoroughly evaluated. This includes an analysis of their efficacy, safety, long-term benefits, and their ability to restore gut microbiota balance, improve digestive health, enhance immune function, and reduce inflammation. The aim is to determine if these non-pharmacological interventions can effectively and safely manage intestinal dysbiosis in children, reducing the need for conventional medications and their side effects. Full article

The aim of the present study was to develop a fermented pistachio beverage as a plant-based alternative to milk-based drinks. For this purpose, a colloidal mill was used to finely grind and homogenize the pistachios to obtain a homogeneous consistency and prevent sedimentation. In addition, lactic acid bacteria fermentation was used to develop unique flavours and characteristics in the final product and to achieve microbiological stability for up to 30 days of storage a 4 °C. The formulated beverages were evaluated for chemical–physical characteristics (pH, organic acid production, and fructose, sucrose, and glucose content), nutritional profile (proximate composition, amino acid and GABA content), and volatile organic composition by HS-SPME-GC/MS analysis. The pistachio-based beverages were characterized by a good source of protein, fat, fiber, and minerals (mainly K and P). The colloidal mill contributed to creating a homogeneous texture and to making the nutrients readily available to the starter microorganisms, which reached concentrations above 10⁸ ufc/mL in the final products. The beverages were characterized by pronounced acidity and some by the presence of acetoin and 2,3-butanedione, volatile components associated with a yogurt- or kefir-like aroma. This innovative approach provides an alternative to traditional milk-based beverages and highlights the role of LAB in the development of nutritious and attractive plant-based beverages. Full article

Kefir has been associated with beneficial effects on its host’s health. The previous works examining the impact of kefir on the immune system focused on milk kefir or the exopolysaccharides and bacterial strains derived from it, while water kefir has not been evaluated. Furthermore, studies have focused on kefir’s ability to modulate immune system hemostasis and exert anti-inflammatory effects, while its specific action on antiviral immunity has not been investigated. Thus, the aim of this work was to examine the potential immunomodulatory effects of water kefir on the intestinal innate antiviral immunity mediated by Toll-like receptor-3 (TLR3). Adult BALB/c mice fed water kefir ad libitum, diluted 1:5, 1:10, or 1:20 in the drinking water, for 6 consecutive days. On day 7, the treated groups and the untreated control mice received an intraperitoneal injection of the TLR3 agonist poly(I:C). Two days after the TLR3 activation, the intestinal damage and the innate immune response were studied. The intraperitoneal administration of poly(I:C) induced inflammatory-mediated intestinal tissue damage, characterized by the upregulation of interferons (IFNs), pro-inflammatory mediators (TNF-α, IL-15, IL-6), and factors involved in epithelial destruction (RAE-1 and NKG2D). The histological analysis of small intestinal samples showed that mice receiving water kefir 1:5 exhibited reduced edema and a lower inflammatory cell infiltration. Kefir-treated mice had significantly lower levels of serum LDH, AST, and ALT as well as intestinal TNF-α, IL-15, IL-6, RAE-1, and NKG2D. This group also showed higher concentrations of intestinal IFN-β, IFN-γ, and IL-10. The treatment with 1:10 of water kefir reduced intestinal damage and modulated cytokines but its effect was significantly lower than the 1:5 treatment, while the water kefir 1:20 did not modify the parameters evaluated compared to control mice. The results indicate that water kefir exerts its immunomodulatory effects in a dose-dependent manner. The in vivo studies allow us to speculate that water kefir can induce two beneficial effects on the intestinal TLR3-mediated immune response: the enhancement of antiviral defenses and the protection against the inflammatory-mediated tissue damage. These protective effects of water kefir require further exploration to understand how water kefir, or its specific molecules/strains, can influence the immune response and to determine the extent of its protection against a real viral challenge. Full article

Nowadays, there has been a significant rise in the consumption of kefir, a functional beverage touted for its perceived health benefits. To offer a high-quality beverage to consumers, it is imperative to scrutinize and fine-tune the fermentation process. This study seeks to investigate the impact of fermentation time and the number of subcultures on the physicochemical, microbiological, and volatile composition, as well as the visual appearance, of kefir beverages obtained from four consecutive 24- or 48-h batch subcultures. All fermented beverages exhibited low lactose, ethanol and acids levels, with counts of viable probiotic lactic acid bacteria and yeast exceeding 10⁶ colony forming units/mL. The four kefir beverages from the 48-h batch subcultures notably showed the lowest total concentrations of volatile compounds, likely due to overfermentation and over-acidification of the beverages. This caused the separation of the whey and curd, along with the formation of large gas bubbles, negatively affecting the visual appearance of the products. These findings emphasize the importance of fine-tuning the fermentation process to ensure the production of high-quality kefir beverages that align with consumer preferences. The four beverages from the 24-h batch subcultures exhibited high microbiological and physicochemical stability during storage at 4 °C for 28 days. Full article

Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time. The taxonomic profiling of metagenomic reads revealed that Lactococcus species, such as Lc. lactis and Lc. cremoris prevailed in khuruud, bryndza, one sample of cottage cheese and khurunga. The latter one together with suluguni-like cheese microbiome was dominated by bacteria, affiliated to Lactobacillus helveticus (32–35%). In addition, a high proportion of sequences belonging to the genera Lactobacillus, Lactococcus and Streptococcus but not classified at the species level were found in the suluguni-like cheese. Lactobacillus delbrueckii, as well as Streptococcus thermophilus constituted the majority in another cottage cheese, kefir and ayran metagenomes. The microbiome of shubat, produced from camel’s milk, was significantly distinctive, and Lentilactobacillus kefiri, Lactobacillus kefiranofaciens and Bifidobacterium mongoliense represented the dominant components (42, 7.4 and 5.6%, respectively). In total, 78 metagenome-assembled genomes with a completeness ≥ 50.2% and a contamination ≤ 8.5% were recovered: 61 genomes were assigned to the Enterococcaceae, Lactobacillaceae and Streptococcaceae families (the Lactobacillales order within Firmicutes), 4 to Bifidobacteriaceae (the Actinobacteriota phylum) and 2 to Acetobacteraceae (the Proteobacteria phylum). A metagenomic analysis revealed numerous genes, from 161 to 1301 in different products, encoding glycoside hydrolases and glycosyltransferases predicted to participate in lactose, alpha-glucans and peptidoglycan hydrolysis as well as exopolysaccharides synthesis. A large number of secondary metabolite biosynthetic gene clusters, such as lanthipeptides, unclassified bacteriocins, nonribosomal peptides and polyketide synthases were also detected. Finally, the genes involved in the synthesis of bioactive compounds like β-lactones, terpenes and furans, nontypical for fermented milk products, were also found. The metagenomes of kefir, ayran and shubat was shown to contain either no or a very low count of antibiotic resistance genes. Altogether, our results show that traditional indigenous fermented products are a promising source of novel probiotic bacteria with beneficial properties for medical and food industries. Full article