Search Results (51)

This study examined Kefiran, an exopolysaccharide derived from milk kefir grains, as a novel biopolymer for encapsulating phenolic extracts from sunflower cake and its antimicrobial properties in the development of natural and functional food ingredients. Kefiran was obtained from kefir grains using three extraction protocols: hot water (M1), hot water with 30% trichloroacetic acid (M2), and mild heat combined with ultrasound at 60 °C (M3). The ultrasound-assisted method produced the highest carbohydrate concentration. Spectrophotometric assays (phenol–sulfuric and Bradford), Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and water-holding capacity were employed to characterize the composition, structure, and morphology of the extracts, revealing well-preserved polysaccharide fingerprints and a highly porous microstructure, consistent with their potential application in food systems. Kefiran was then evaluated as an encapsulating agent in complex coacervation at pH 3.75, using three Kefiran-based wall formulations (M1, M2, and M3) with gum arabic and whey protein isolate (WPI) as co-wall materials, and their performance was compared with gum arabic and WPI controls. Across formulations, coacervate microcapsules achieved high encapsulation efficiencies (83–93%), tunable particle sizes, and predominantly negative zeta potentials, indicative of good colloidal stability. The Kefiran extract and coacervate microcapsules demonstrated significant antioxidant and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, with minimum inhibitory concentrations ranging from 250 to 1000 µg/mL. The findings support ultrasound-extracted Kefiran as a multifunctional biopolymer suitable for bioactive delivery and as a natural antimicrobial component in advanced functional food formulations. Full article

This study evaluated the fermentation kinetics and properties of kefir beverages produced from whole milk using milk kefir grains (MKGs) or water kefir grains (WKGs) over 48 h. MKGs showed higher initial microbial loads and promoted rapid acidification, with pH decreasing from 6.70 to 4.99 and significant production of lactic acid (10.58 g/L) and ethanol (5.17 g/L), compared with WKGs (final pH 6.20, <0.5 g/L lactic acid, and <0.3 g/L ethanol). However, the final concentration of acetic acid in WKG fermentation (1.93 g/L) was comparable to that in MKG fermentation (2.02 g/L). Microbial populations increased in both systems, exceeding 10⁶ CFU/mL—one of the requirements for conferring probiotic relevance to a beverage—with MKGs reaching higher counts. Lactose and protein consumption were greater in MKGs, suggesting more intense metabolic activity. Fermentation enhanced nutritional value by increasing vitamins B2, B3, B5, and pyridoxine, while vitamin D3 decreased. Mineral composition remained largely unchanged. Volatile analysis identified 31 compounds: MKGs favored fatty acids and lactones associated with creamy notes, whereas WKGs promoted ester formation and fruity aromas. Overall, both grain types produced microbiologically safe beverages with distinct biochemical and sensory profiles, demonstrating the feasibility of using WKGs for milk fermentation. Full article

Kefir grains are a valuable source of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) with potential applications in fermented dairy products. In this study, LAB isolated from kefir grains originating from five regions were screened for EPS production and probiotic-related properties. Three strains, Lactiplantibacillus plantarum XZ61, Lactobacillus kefiranofaciens EG10, and Lentilactobacillus kefiri EG12, were selected based on high EPS yield, antimicrobial activity, antioxidant capacity, and tolerance to acidic and bile salt conditions. After optimization, the highest EPS yield (539.57 μg/mL) was obtained from strain EG10.The purified EPS consisted of two molecular weight fractions (≈1.4 and 23~25 kDa) and was rich in mannose (33.38~61.58%). Among the three EPS, EG10-EPS exhibited superior emulsifying and flocculating properties comparable to commercial stabilizers, as well as notable ABTS^•+ and hydroxyl radical scavenging activities. Furthermore, co-fermentation of L. kefiranofaciens EG10 with conventional yogurt starter cultures significantly improved exopolysaccharide content, water-holding capacity, texture, and antioxidant activity of fermented milk, particularly in cow milk. These results demonstrate the potential of kefir-derived EPS-producing LAB as natural functional cultures for fermented dairy applications. 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

Obesity is a complex metabolic disorder characterized by excessive accumulation of adipose tissue, resulting from an imbalance between energy intake and expenditure. It is associated with an increased risk of chronic diseases such as type 2 diabetes, cardiovascular disease, and cancer. Kefiran is a water-soluble exopolysaccharide produced by lactic acid bacteria, Lactobacillus kefiranofaciens, in kefir grains, composed primarily of glucose and galactose. It has garnered scientific interest due to its antioxidant, anti-inflammatory, and antimicrobial properties. Rice Kefiran (RK) is a functional food made with culturing L. kefiranofaciens in a medium containing rice. It is standardized to contain at least 5 mg/g of kefiran. This study investigated the anti-obesity effect of RK on a high-fat diet (HFD)-induced obese mouse model. HFD-fed mice exhibited marked increases in body weight gain (10.3 g vs. 2.0 g in controls) and adipose tissue mass (2.4 g vs. 0.4 g in controls). RK administration significantly attenuated weight gain to 8.3 g and 6.0 g at doses of 10 and 50 mg/kg, respectively, and reduced adipose tissue mass to 2.2 g (RK10) and 1.7 g (RK50). Oral glucose tolerance testing revealed impaired glucose clearance in HFD-fed mice, with blood glucose levels of 403.5 mg/dL at 15 min and 314.6 mg/dL at 120 min, compared with 348.8 mg/dL and 232.2 mg/dL in controls. RK treatment improved glucose tolerance, particularly at 50 mg/kg, reducing glucose levels to 359.0 mg/dL at 15 min and 263.8 mg/dL at 120 min. Biochemical analyses demonstrated that RK significantly reduced serum total cholesterol (213.6 mg/dL in HFD vs. 178.0 and 184.0 mg/dL in RK10 and RK50), triglycerides (379.0 mg/dL in HFD vs. 228.8 and 234.6 mg/dL), and non-esterified fatty acids (0.89 mEq/mL in HFD vs. 0.54 and 0.35 mEq/mL), while phospholipid levels remained unchanged. Furthermore, RK increased serum nicotinamide phosphoribosyltransferase (NAMPT) levels from 15.8 ng/mL in HFD-fed mice to 30.0 and 50.0 ng/mL in the RK10 and RK50 groups, respectively, and restored hepatic NAD⁺/NADH ratios toward control levels (1.78 µmol/L in HFD vs. 1.90 µmol/L and 2.07 µmol/L in RK10 and RK50). Gene expression analysis showed that RK increased Nampt mRNA expression and decreased the mRNA expression of adipogenic and lipogenic genes, including Srebp-1c, Acc-1, and Fas. These findings suggest that RK may ameliorate obesity-related metabolic disturbances and its associated metabolic dysfunctions by modulating lipid metabolism, glucose tolerance, and NAD⁺ biosynthesis pathways. Full article

Water kefir is a non-dairy fermented water drink which includes lactic acid bacteria, acetic acid bacteria and yeasts which provide probiotic as well as antioxidant properties. Prunus armeniaca (apricot) is a promising raw material to develop a functional beverage because it is rich in carotenoids, vitamins, and phenolics. Coconut water is a natural hydrating substance and plant-based substrate. The aim of this study was to prepare and characterize apricot-coconut water kefir beverage, (ACWB) a fermented beverage having 20 g (w/v) dried apricot, 8 g (w/v) brown sugar, and 8 g (w/v) water kefir grains fermented together in 100 mL coconut water and compare its physicochemical, microbial, and antioxidant properties with a control sample excluded with dried apricot but having same concentration of rest of the ingredients. After fermentation, total soluble solids (TSS), pH, titratable acidity (TA), water activity (aw), total bacterial count (TBC), DPPH radical-scavenging activity, and total phenolic contents (TPC) were measured. ACWB exhibited significantly higher values (p < 0.05) in terms of TSS (10.07 ± 0.01 °Brix), TA (0.298 ± 0.01%), and TBC (1.92 × 10⁷ CFU/mL), with lower pH (3.98 ± 0.07) and aw (0.94 ± 0.02) compared to the control. Enhanced antioxidant activity (DPPH = 62.7 ± 0.86%) and TPC (19.92 ± 0.32 mg CE/100 mL) confirmed its superior bioactive potential. Sensory evaluation of ACWB also found it to be more preferred, with statistically significant difference in majority of the tested attributes. The apricot supplement enhanced the fermentation activity, microbial growth, as well as the antioxidant capacity of the end product, creating a stable, tangy, and nutritionally enriched non-dairy functional beverage that could be consumed by healthy and lactose intolerant consumers. Full article

Nowadays, consumer demand for functional foods with health benefits has grown significantly. In response to this trend, a variety of potentially probiotic foods have been developed—most notably kefir and kefir-like beverages, which are highly appreciated for their tangy flavor and health-promoting properties. Traditionally, kefir is made by fermenting cow’s milk with milk kefir grains, although milk from other animals—such as goats, ewes, buffalo, camels, and mares—is also used. Additionally, non-dairy versions are made by fermenting plant-based milks (such as coconut, almond, soy, rice, and oat) with the same type of grains, or by fermenting fruit and vegetable juices (e.g., apple, carrot, fennel, grape, tomato, prickly pear, onion, kiwifruit, strawberry, quince, pomegranate) with water kefir grains. Despite their popularity, many aspects of kefir production remain poorly understood. These include alternative production methods beyond traditional batch fermentation, kinetic studies of the process, and the influence of key cultivation variables—such as temperature, initial pH, and the type and concentration of nutrients—on biomass production and fermentation metabolites. A deeper understanding of the fermentation process can enable the production of kefir beverages tailored to meet diverse consumer preferences. Full article

Functional beverages enhance the nutritional value of their ingredients by increasing the levels of bioactive components, such as probiotics. To achieve consumer acceptance, functional beverages must be both palatable and nutritious. This study investigates the fermentation of quinoa and cherimoya at two temperatures (25 °C and 32 °C) using water kefir grains. The aim was to create a fermented mix that is both balanced and appealing to consumers. The response variables measured were the concentrations of lactic acid bacteria (LAB) and yeasts (CFU mL⁻¹), as well as the overall liking (OL). Ten semi-trained panellists evaluated them using a seven-point hedonic scale. All three developed models for LAB and yeast growth, and OL exhibited R² values exceeding 0.8, indicating a strong model fit and simultaneous optimisation considering the three key responses. At a temperature of 25 °C, the mass fractions of the mixes containing quinoa puree (QP) and cherimoya juice (CJ) were 0.13 and 0.87, respectively. Under optimal conditions, the LAB and yeast increased by 4.2 and 4.4 log units, respectively. Moreover, a significant 62% increase in protein levels and a notable 82% decrease in ascorbic acid were observed after 48 h of fermentation, likely caused by the Maillard reaction. Full article

Fermented beverages have been highlighted for their beneficial effects on health, especially due to the presence of probiotic microorganisms. This study aimed to develop and characterize a beverage fermented from the aqueous extract of licuri (Syagrus coronata) with grains of milk kefir and water kefir. Physical–chemical properties, microbial viability, storage stability, and in vitro resistance to the gastrointestinal tract (GIT), as well as microbiological safety and identification of isolated bacteria, were evaluated. The grains were fermented in licuri for 24 and 48 h, and the samples were compared with their respective controls. The analyses revealed that the licuri drink favored the growth of kefir grains, maintaining adequate microbial viability (>7 log CFU mL⁻¹ for lactic acid bacteria and >4 log CFU mL⁻¹ for yeasts), with good resistance to GIT (>60%) and physical–chemical properties for 20 days. The bacterial isolate was identified as Lacticaseibacillus paracasei, with a satisfactory safety profile. Licuri extract is therefore a promising matrix for the development of non-dairy functional beverages with potential probiotic properties. Full article

Kefiran, the extracellular polysaccharide produced from the Generally Recognized as Safe (GRAS) bacteria in kefir grains, with its well-documented functional and health-promoting properties, constitutes a promising biopolymer with a variety of possible uses. Its compatibility with other biopolymers, such as milk proteins, and its ability to form standalone cryogels allow it to be utilized for the fabrication of films with improved properties for applications in the food and biomedical–pharmaceutical industries. In the present work, the properties of kefiran films were investigated in the presence of milk proteins (sodium caseinate, native and heat-treated whey proteins, and their mixtures), alongside glycerol (as a plasticizer) and cryo-treatment of the film-forming solution prior to drying. A total of 24 kefiran films were fabricated and studied for their physical (thickness, moisture content, water solubility, color parameters and vapor adsorption), mechanical (tensile strength and elongation at break), and optical properties. Milk proteins increased film thickness, solubility and tensile strength and reduced water vapor adsorption. The hygroscopic effect of glycerol was mitigated in the presence of milk proteins and/or the application of cryo-treatment. Glycerol was the most effective at reducing the films’ opacity. Heat treatment of whey proteins proved to be the most effective in increasing film tensile strength, reducing, at the same time, the elongation at break, while sodium caseinates in combination with cryo-treatment resulted in films with high tensile strength and the highest elongation at break. Cryo-treatment, carried out in the present study through freezing followed by gradual thawing of the film-forming solution, proved to be the most effective factor in decreasing film roughness. Based on our results, proper selection of the film-forming solution composition and its treatment prior to drying can result in kefiran–glycerol films with favorable properties for particular applications. Full article

The rising interest in functional fermented beverages, such as kombucha and water kefir, has stimulated research into their health benefits. This study aimed to investigate the combined bioactive potential of kombucha and water kefir by fermenting a novel medium prepared by mixing them in a 1:1 v/v ratio. The fermentation process involved using both SCOBY and water kefir grains (WKGs) separately, as well as co-cultivation, to explore the bioactive properties of the three fermented beverages. Samples were analyzed at 24, 48, and 72 h for changes in pH, microorganism growth, and concentrations of flavonoids and phenolics. Antioxidant activity was assessed using DPPH, ABTS, and FRAP tests, alongside colorimetric analysis and enzyme inhibition assays against α-amylase, α-glucosidase, and lipase. The results demonstrated that longer fermentation times increased both bioactive compound content and antioxidant capacity. The highest phenolic concentration was found in the WKG-fermented mixture (47.58 ± 2.13 mg GAE/100 mL), while the highest iron-reducing capacity was observed in the product fermented with both WKGs and the co-culture of SCOBY-WKGs. Additionally, SCOBY fermentation showed significant inhibitory activity (over 70%) against digestive enzymes. These findings suggest that co-fermenting kombucha and water kefir represents a promising alternative to traditional water kefir, with improved bioactive compound profiles. Full article

This study aimed to isolate and characterize microorganisms from water kefir beverage for their functional properties. Five lactic acid bacteria (LAB) strains were isolated: three Leuconostoc citreum strains (LB4, LB6, LB13) and two Lactococcus lactis strains (LB5, LB25), identified via 16S rRNA sequencing, along with three Saccharomyces cerevisiae yeast strains (Y7, Y9, Y10), confirmed by 18S rDNA sequencing. Due to the high genetic and phenotypic similarity within each species, one representative strain from each (LB4, LB5, Y9) was selected for further analysis. These strains showed potential probiotic properties, including tolerance to acid and bile, high auto-aggregation, and hydrophobicity. The LAB strains were sensitive to gentamicin, and their supernatants inhibited the growth of tested pathogenic bacteria. The cumulative probiotic potential (CPP) scores were 93.33% for Lc. citreum LB4 and L. lactis LB5, and 100% for S. cerevisiae Y9. Furthermore, the fermentation potential of these strains was evaluated in a green tea beverage using three co-culture formulations. Among the formulations tested, the BF1 beverage, fermented by F1 (40% LB4, 40% LB5, and 20% Y9), demonstrated optimal physicochemical, microbiological, and sensory properties. Notably, while the individual strains did not show anti-inflammatory activity, the BF1 beverage formulation exhibited this effect, suggesting a synergistic interaction during fermentation. Full article

Water kefir is a non-dairy fermented beverage that ferments water kefir grains in a sucrose solution. These grains harbor a diverse microbiota, including lactic acid bacteria, acetic acid bacteria, and yeast species. The composition of water kefir is primarily influenced by cultivation conditions and the microbiota profile of the grains, resulting in fermentation metabolites such as ethanol, lactic acid, mannitol, acetic acid, glycerol, and other organic acids. However, this microbial diversity can vary depending on the origin of the grains, the fermentation substrate, and environmental conditions. As it is a potentially beneficial product for health, interest in kefir consumption has increased in recent years. Specific legislation for water kefir is still scarce, and despite potentially probiotic microorganisms, water kefir is not classified as a probiotic, but it fits the definition of a potentially functional food due to its health benefits. Studies demonstrate the potential health benefits of water kefir in terms of anti-inflammatory, antimicrobial, antioxidant, antidiabetic, and intestinal health effects. However, industrial-scale production and starter cultures have not yet been developed. This study aims to comprehensively review water kefir, exploring its potential health benefits, fermentation process, microbial diversity, and regulatory aspects. Full article

The cheese industry produces millions of tons of lactose-rich whey yearly, of which 50% is discharged into water and soil, leading to significant environmental challenges. In Mexico, cheese whey is repurposed for traditional cheese production. However, another by-product named secondary whey (SW) remains. This study focused on the production of exopolysaccharides (EPSs) via SW fermentation of kefir grains, yielding 632.6 ± 30.8 mg/L of a freeze-dried solid, and the carbohydrate-to-protein ratio stood at 2.89, corresponding to the bound EPS protein content. Through the analysis of Fourier Transform Infrared Spectroscopy (FTIR) spectra, it was determined that EPSs were successfully produced, as a signal was observed between 1200 and 1000 cm⁻¹, characteristic of the glycosidic bonds in polysaccharides. Full article

The aim of this study was to use different concentrations of lemon juice and honey to improve the formulation of a green tea water kefir (GTWK) beverage by applying a central composite design (CCD). Honey’s concentration was 10–50% and lemon juice concentration was 1–5%, these were used as the independent factors, whereas pH, bacteria and yeasts’ count, total phenolic content, % DPPH^. scavenging activity, and overall acceptability were used as the dependent factors. The optimal concentration of honey and lemon juice for highest microbial count, antioxidant activities and overall acceptability was 42.85% and 1.771%, respectively. The analysis of variance revealed that the model was well-fitting, with R² ranging from 87.27% to 96.95%, adj-R² ranging from 78.17% to 94.26% and a non-significant lack of fits. The optimized fermented beverage showed antibacterial potential against Echerichia coli ATCC11229, Staphylococcus aureus ATCC6538 and Salmonella typhimirium ATCC14028 strains. The anti-inflammatory activity was evaluated on CaCo-2 and RAW 264.7 cells. According to ELISA assay, a significant decrease (p < 0.05) in TNF-α concentration was found after inflammatory stimulation, from 1205.41 ± 55.87 pg/mL to 478.17 ± 69.12 pg/mL. Full article