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BACKGROUND RESULTS CONCLUSION While yogurt is the leading fermented milk product, kefir is at the top of the beverage scale. Milk proteins, on the other hand, show specific functions that positively affect healthy nutrition due to the bioactive components, that they provide the necessary amino acids for growth and development.In our study, kefir, a functional product enriched with whey proteins, casein and skimmed milk powder, which are the natural components of milk, was produced. Added‐protein kefir samples were applied the in vitro digestion protocol, static method. In order to observe different protein behaviors, samples were taken pre‐digestion, at 120th minute and at 240th minute of digestion protocol. ACE and Antioxidant capacity determination analyzes were carried out. While ACE inhibition values were in the range of 78.63–90.30% pre‐digestion, they changed in the range of 86.97–96.38% after gastrointestinal digestion. It was determined that the ACE inhibition values of the control sample remained at the lowest level at all stages of digestion and that the difference between all of samples was significant (P < 0.05). Antioxidant activity value ranging from 0.3615–0.5512 meq Ascorbic acid/μg before digestion was determined as 1.3796–1.9313 meq Ascorbic acid/μg after gastrointestinal digestion (P < 0.05).Kefir samples containing whey protein stand out with their high potential in terms of both antioxidant activity capacity and ACE inhibition activity at all stages of digestion. Considering their therapeutic effects in fermented products, it is thought that whey proteins among milk proteins will be important alternative sources to enrich the protein content in kefir production. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Depression is a common psychological disorder, and traditional therapeutic drugs often result in side effects such as emesis, dry mouth, headache, dysentery and constipation. Probiotics and goat milk have garnered widespread attention for their ability to modulate immune function and regulate the endocrine system, and for their anti‐inflammatory effects. In this work, the effects of Tibetan goat kefir on the behavior, immune status, neuroendocrine response and gut microbiological composition of chronic unpredictable mild stress (CUMS) mouse models were evaluated.The results indicated that Tibetan kefir goat milk significantly alleviated behavioral despair in mice. Furthermore, the results demonstrated that Tibetan kefir goat milk mitigated the inflammatory response in the mice and moderated the hyperactivity of the hypothalamic–pituitary–adrenal axis and the expression of brain‐derived neurotrophic factor. Meanwhile, chronic stress‐induced gut microbial abnormalities were restored. In addition, the correlation between gut microbiota and nervous system was evaluated.These results explained the potential mechanism of Tibetan kefir in the antidepressant effect on the CUMS model and enriched diets for depressed patients. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This is the first study that investigates the effect of kefir with an emphasis on the production of short-chain fatty acids (SCFAs) during the fermentation process in food products. The products developed and characterized were an artisanal cream cheese without cream and one with added cream, and for the analysis of the fatty acid profile, both cream cheeses were compared with commercial cream cheese. The artisanal cream cheese had a high amount of lactic acid bacteria characterizing the product formed by Lactobacilli and a low concentration of lactose due to the fermentation process. Compared to commercial cream cheese, our products without and with added cream had a higher concentration of short-chain fatty acids (SCFAs), especially butyric acid, which is important for the health of the gastrointestinal tract, omega 3, and oleic fatty acid, which has been associated with the prevention and control of some diseases. Overall, the artisanal cream cheese cream with fermented cream with kefir grains is a functional product with an innovative character compared to current products on the market and was well accepted by the younger public. This new product comes as an option for those who need to change their eating habits and maintain a healthy lifestyle. [ABSTRACT FROM AUTHOR]

Dairy products are an important source of protein and other nutrients in the Mediterranean diet. In these countries, the most common sources of milk for producing dairy products are cow, goat, sheep, and buffalo. Andalusia is traditionally the largest producer of goat milk in Spain. Kefir is a fermented product made from bacteria and yeasts and has health benefits beyond its nutritional properties. There is a lack of knowledge about the molecular mechanisms and metabolites that bring about these benefits. In this work, the combination of analytical techniques (GC-FID, UHPLC-MS-QToF, GC-QqQ-MS, and GC-ToF-MS) resulted in the detection of 105 metabolites in kefir produced with goat milk from two different thermal treatments (raw and pasteurized) fermented at four time points (12, 24, 36, and 48 h, using 0 h as the control). Of these, 27 metabolites differed between kefir produced with raw and pasteurized milk. These changes could possibly be caused by the effect of pasteurization on the microbial population in the starting milk. Some interesting molecules were identified, such as shikimic acid, dehydroabietic acid, GABA, and tyramine, which could be related to antibacterial properties, strengthening of the immune system, and arterial pressure. Moreover, a viability assay of the NIRS technique was performed to evaluate its use in monitoring the fermentation and classification of samples, which resulted in a 90% accuracy in comparison to correctly classified samples according to their fermentation time. This study represents the most comprehensive metabolomic analysis of goat milk kefir so far, revealing the intricate changes in metabolites during fermentation and the impact of milk treatment. [ABSTRACT FROM AUTHOR]

Four dairy foods processing by-products (acid whey permeate [AWP], buttermilk [BM], sweet whey permeate [SWP], and sweet whey permeate with added milk fat globule ingredient [SWP+MFGM]) were fermented for 4 wk and compared with traditional kefir milks for production of novel kefir-like dairy products. Sweet whey permeates and SWP supplemented with 1.5% milk fat globule membrane (MFGM) proved to be the most viable by-products for kefir grain fermentation, exhibiting diverse abundance of traditional kefir microorganisms and positive indicators of bioactive properties. Grain viability was assessed with shotgun metagenomics, texture profile analysis, live cell counts, and scanning electron microscopy. Assessed bioactivities of the kefir-like products included antibacterial, antioxidant, potential anticancerogenic properties, and membrane barrier effects on human colorectal adenocarcinoma Caco-2 cells. All kefir grains were most abundant in Lactobacillus kefiranofaciens when analyzed with shotgun metagenomics. When analyzed with live cell counts on selective media, AWP kefir-like product had no countable Lactococcus spp., indicating suboptimal conditions for kefir grain microbiota survival and application for fermented dairy starter culture bacterium. Live cell counts were affirmed with kefir grain surface scanning electron microscopy images. The SWP treatment had the most adhesive kefir grain surface, and SWP+MFGM had the largest exopolysaccharide yield from grain extraction. All kefir and kefir-like products were able to achieve a 6-log reduction against Listeria innocua and Escherichia coli. Traditional milk kefirs had the highest antioxidant capacity for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid; ABTS) assay. The AWP formulation had a significantly higher DPPH antioxidant activity compared with the other kefir and kefir-like products, and SWP had the lowest Trolox equivalence concentration in the ABTS assay. Sweet whey and supplemented milk fat sweet whey had upregulation of Cldn-1 and Ocln-1 gene expression, which correspond with a significant increase in transepithelial electrical resistance. [ABSTRACT FROM AUTHOR]

Kefir milk, known for its high nutritional value and health benefits, is traditionally produced by fermenting milk with kefir grains. These grains are a complex symbiotic community of lactic acid bacteria, acetic acid bacteria, yeasts, and other microorganisms. However, the intricate coexistence mechanisms within these microbial colonies remain a mystery, posing challenges in predicting their biological and functional traits. This uncertainty often leads to variability in kefir milk's quality and safety. This review delves into the unique structural characteristics of kefir grains, particularly their distinctive hollow structure. We propose hypotheses on their formation, which appears to be influenced by the aggregation behaviors of the community members and their alliances. In kefir milk, a systematic colonization process is driven by metabolite release, orchestrating the spatiotemporal rearrangement of ecological niches. We place special emphasis on the dynamic spatiotemporal changes within the kefir microbial community. Spatially, we observe variations in species morphology and distribution across different locations within the grain structure. Temporally, the review highlights the succession patterns of the microbial community, shedding light on their evolving interactions.Furthermore, we explore the ecological mechanisms underpinning the formation of a stable community composition. The interplay of cooperative and competitive species within these microorganisms ensures a dynamic balance, contributing to the community's richness and stability. In kefir community, competitive species foster diversity and stability, whereas cooperative species bolster mutualistic symbiosis. By deepening our understanding of the behaviors of these complex microbial communities, we can pave the way for future advancements in the development and diversification of starter cultures for food fermentation processes. [ABSTRACT FROM AUTHOR]

Introduction: Kefir beverage has beneficial microorganisms that have healthgiving properties; therefore, they have a good potential to be probiotic. This study evaluated the probiotic potential, technological, and safety characteristics of Enterococcus faecalis, Lactococcus lactis, and Pichia fermentans isolated from traditional kefir beverages. Method: First, isolates were evaluated in terms of resistance to acid, alkali, bile salts, trypsin, and pepsin of the gastrointestinal tract. The auto-aggregation and co-aggregation ability of isolates were measured using spectrophotometry. Antimicrobial activities were assayed against important food-borne pathogens using the agar well diffusion method. Moreover, gamma-aminobutyric acid (GABA) production was investigated by thin-layer chromatography (TLC). Result: Among the isolates, P. fermentans had an 85% total survival rate, but its amount reached below 6 log CFU/ml which is considered non-resistant, and it showed the highest auto-aggregation (74.67%). Moreover, only L. lactis showed antimicrobial activity and had the highest co-aggregation with E. coli PTCC 1338 (54.33%) and L. monocytogenes ATCC 7644 (78%). Finally, an evaluation of the technological and safety characteristics of the strains showed that the strains produced GABA and were safe. Discussion: Although the isolates were not resistant to the gastrointestinal tract, their supernatant contained valuable natural compounds, including antioxidants, GABA, and antimicrobials, which can be used to produce functional foods and medicines. In addition, other approaches, such as increasing the initial number of strains, using foods as carriers of isolates, and encapsulating the isolates, can effectively increase the survivability of isolates in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

The growing interest in fermented dairy products is due to their health-promoting properties. The use of milk kefir grains as a starter culture made it possible to obtain a product with a better nutritional and biological profile depending on the type of milk. Cow, buffalo, camel, donkey, goat, and sheep milk kefirs were prepared, and the changes in sugar, protein, and phenol content, fatty acid composition, including conjugated linoleic acids (CLAs), as well as antioxidant activity, determined by ABTS and FRAP assays, were evaluated and compared. The protein content of cow, buffalo, donkey, and sheep milk increased after 24 h of fermentation. The fatty acid profile showed a better concentration of saturated and unsaturated lipids in all fermented milks, except buffalo milk. The highest content of beneficial fatty acids, such as oleic, linoleic, and C18:2 conjugated linoleic acid, was found in the cow and sheep samples. All samples showed a better antioxidant capacity, goat milk having the highest value, with no correlation to the total phenolic content, which was highest in the buffalo sample (260.40 ± 5.50 μg GAE/mL). These findings suggested that microorganisms living symbiotically in kefir grains utilize nutrients from different types of milk with varying efficiency. [ABSTRACT FROM AUTHOR]

Water kefir grains are an important source of probiotics, mainly containing lactic acid bacteria and yeasts. The aim of this study is to investigate the changes in microbial and chemical properties of water kefir grains during 1‐month storage at +4°C and −18°C. The initial content of lactobacilli, lactococci, and yeast in water kefir grains was 6.06, 6.33, and 5.93 log CFU/g, respectively. The number of lactobacilli, Lactobacillus acidophilus, and Bifidobacterium spp. in the water kefir grains were comparable, with slight changes at the end of refrigerated storage (p >.05). Lactococci and yeasts decreased significantly after both storage conditions compared to the initial content (p <.05). The dry matter and ash contents remained unchanged during storage (p >.05). Water kefir grains contained significant amounts of calcium, vitamin B2, vitamin B6, vitamin B7, and vitamin B12. Storage at both +4°C and −18°C did not affect the mineral and vitamin contents, except for Cu and Vitamin B2. The results indicate that the water kefir grains remained viable after storage at both temperatures. If water kefir grains need to be stored, it is recommended to store them at +4°C in sugared water as it ensures better survivability of the microbiota of the grains. [ABSTRACT FROM AUTHOR]

Kefir grains are symbiotic microbiota starters in the production of dairy products such as fermented milk, kefir. In recent decades, microbial symbiosis in kefir grains and its role in fermentation have attracted a lot of attention. This study aimed to obtain novel kefirs with different characteristics by "stimulating" kefir grains with juices of Actinidia chinensis, Solanumly copersicum, Daucus carrot, and Lactuca sativa, respectively, before being used as starter cultures for kefir fermentation. Then, compositions of the predominant microbiota in novel kefirs were determined. These novel kefirs showed changes in their physiochemical characteristics and enhanced antimicrobial activities against Shigella dysenteriae, Candida albicans, Staphylococcus aureus, Serratia marcescens, and Escherichia coli. Therefore, preprocessing of kefir grains with natural substrates could be a feasible strategy in the production of novel kefirs with different flavors and various health benefits. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the behavior of Listeria monocytogenes during the manufacture and storage of artisanal kefir. A five-strain cocktail of L. monocytogenes was introduced (at ca. 3.0 log10 CFU/mL) into UHT milk as a pre-fermentation contaminant. The growth of L. monocytogenes, lactic acid bacteria and yeasts was monitored during the 24-h fermentation period of milk with two types of kefir grains at 20 °C and the subsequent storage of kefir under adequate (4 °C) and inadequate (10 °C) refrigerated-storage conditions. L. monocytogenes grew into much higher cell densities (5.3–5.8 log10 CFU/mL) by the end of the fermentation period, but the final (24-h) counts were substantially lower than those obtained in the corresponding control trials with unfermented milk (7.2 log10 CFU/mL). The growth rate of L. monocytogenes during fermentation differed depending on the type of kefir grain used. During the subsequent 11-day storage of the kefir filtrates at 4 °C or 10 °C, the behavior of L. monocytogenes varied from no growth to further population increases (of up to 1.1 log10 CFU/mL), depending on the storage temperature, but also depending on the type of kefir grain and the grain surface-to-weight ratio that had been used to ferment the milk. This study highlights the need for strict adherence to good hygiene practices during artisanal kefir making and shows that L. monocytogenes can sustain considerable growth during milk fermentation and further grow during the subsequent cold storage of kefir, particularly under inadequate refrigerated storage conditions. [ABSTRACT FROM AUTHOR]

Kefir is a fermented dairy product claimed to confer many health-promoting effects, but its acidic taste is not appealing to some consumers. Therefore, the aim of this study was to enhance the functional and sensorial quality attributes of kefir through fortification with encapsulated blackberry juice (EBJ). The blackberry juice was successfully encapsulated via freeze-drying using lentil protein isolate (LPI) as the carrier. The encapsulated blackberry juice showed good physicochemical, functional, and morphological properties, as well as microbiological safety for use as a food additive. The kefir was fortified with EBJ in concentrations of 1, 2.5, 5, and 7.5% (w/w), stored for up to 28 days under refrigeration, and periodically evaluated. Parameters such as the viscosity, titrable acidity, and pH indicate that the kefir fortification did not affect its stability during storage. EBJ significantly increased the antioxidant properties of the kefir, depending on the fortification level. Additionally, all the fortified samples provided more anthocyanins than the daily recommended intake. Microbiological profiling demonstrated that good laboratory practice and hygiene were implemented during the experiments. Finally, the panelists showed that higher EBJ concentrations in the kefir resulted in greater overall acceptability, indicating that this encapsulate has the potential to be a substitute synthetic color additive in the dairy industry. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The various forms of interactions that microorganisms engage in within fermented foods result in distinct metabolic product patterns. Fermentation products often feature both yeasts and bacteria, each possessing characteristics that can enhance the overall quality of the food, thus benefiting consumers. Kefir, a fermented milk originating from grains containing a unique and intricate blend of bacteria and yeasts living in a symbiotic relationship, is a valuable model for studying the evolution of the interactions between yeasts and bacteria. Targeted metagenomics was applied to investigate the microbiome of a batch of traditional Romanian kefir and further examine the growth and metabolic properties of the dominant yeast and bacterial strains isolated from this batch. In contrast to yeast, which is either unaffected or harmed by the presence of bacteria, our study revealed that a specific strain of Lactobacillus (L. rhamnosus) derived from the kefir batch benefited from the presence of Saccharomyces cerevisiae. The analysis of short-chain fatty acids (SCFAs) produced by in vitro cultures of these two chosen strains indicated significant changes in SCFA levels compared to single cultures. The dynamic interactions described in this and other studies on kefir emphasize the importance of a more profound comprehension of the ecological mechanisms governing interactions between yeast, bacterial, and mammalian cells. [ABSTRACT FROM AUTHOR]

Sufficient intake of probiotics has been shown to help in the digestion, protect the body against pathogenic microorganisms and boost the immune system. Recently, due to high prevalence of milk allergies and lactose intolerance in population, the non-dairy based probiotic alternative are becoming increasing popular. In this context, the oat milk and soya milk-based fermented products can be an ideal alternative for the development of Lactic acid bacteria bacteria based probiotics. These bacteria can not only improve the product's flavor and bioavailability but also increases its antibacterial and antioxidant capabilities due to fermentation process. The purpose of the resent work was to assess the antioxidant and probiotic properties of oat and soy milk that had been fermented with three different strains of Lactiplantibacillus plantarum (L. plantarum) including L. plantarum 12-3, L. plantarum K25, and L. plantarum YW11 isolated from Tibetan Kefir. Different validated assays were used to evaluate the probiotic properties, adhesion and survival in the digestive system (stomach, acid and bile salts resistance), antioxidant and antimicrobial activities and safety (ABTS and DPPH scavenging assays) of these strains. Results of the study showed that soya milk and oat milk fermented with L. plantarum strains possess promising probiotic, antibacterial and antioxidant properties. These results can be helpful to produce dairy-free probiotic replacements, which are beneficial for those who are unable to consume dairy products due to dietary or allergic restrictions. [ABSTRACT FROM AUTHOR]

Kefir is a fermented milk beverage with potential health benefits due to its antioxidant, antimicrobial, and antidiabetic effects. This study aimed to optimize the formulation of a probiotic kefir beverage made with cheese whey, milk, and palm sap using the simplex-centroid mixture design method (SCMD). Microbial count, physicochemical characteristics, and acceptability were evaluated. The optimized formulation contained 16.6% (w/v) cheese whey, 78.6% (w/v) palm sap, and 4.8% (w/v) milk, and showed high antioxidant activity (by using 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) and acceptable sensory properties (based on a preference scale of 1–9). This study confirms the potential of palm sap in the formulation of novel kefir beverages as a source of probiotics. [ABSTRACT FROM AUTHOR]

Water kefir is a non‐dairy probiotic beverage. It is obtained by fermentation of water kefir grains with a sugar solution. This study aims to determine the properties of water kefir beverages obtained by fermentation of mandarin and persimmon‐containing water for 42 h. According to microbiological results, both fruits containing water samples provided a high number of lactic acid bacteria and yeasts. Moreover, after fermentation, pH, Brix, and dry matter content did not significantly differ. On the other hand, fructose, maltose, and acetic acid contents of mandarin water kefir are significantly higher than persimmon water kefir (p <.05). Persimmon water kefir had higher total phenolic contents, twice as much as mandarin water kefir (p <.05). Both water kefirs had good color properties. The organoleptic acceptability of the fruit water kefirs was promising. [ABSTRACT FROM AUTHOR]

The purpose of this work was to evaluate the selected physicochemical, rheological, and sensory properties of a new whey-enriched carrot juice beverage (carrot juice: whey ratios of 100:0; 95:5; 85:15; 75:25; 65:35) fermented with milk or water kefir starter cultures over a storage period of 21 days (at 4 ± 1 °C). In general, for all tested samples, the values of total soluble solids, pH, and density decreased with increasing storage time. In contrast, the values of ethanol, degree of fermentation, and total dissolved solids increased with the prolongation of the storage time. Furthermore, it was found that all the model samples exhibited pseudoplastic behavior. Based on the sensory analysis performed, samples containing 25% (w/w) whey were evaluated as the most acceptable. Last but not least, the present study can serve as a basis for optimizing the manufacturing technology of a novel fermented vegetable beverage enriched with whey. [ABSTRACT FROM AUTHOR]

Copyright of Food Science & Engineering Research is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Kefir is a fermented beverage made of a symbiotic microbial community that stands out for health benefits. Although its microbial profile is still little explored, its effects on modulation of gut microbiota and production of short-chain fatty acids (SCFAs) seems to act by improving brain health. This work aimed to analyze the microbiota profile of milk kefir and its effect on metabolism, oxidative stress, and in the microbiota-gut-brain axis in a murine model. The experimental design was carried out using C57BL-6 mice (n = 20) subdivided into groups that received 0.1 mL water or 0.1 mL (10% w/v) kefir. The kefir proceeded to maturation for 48 h, and then it was orally administered, via gavage, to the animals for 4 weeks. Physicochemical, microbiological, antioxidant analyzes, and microbial profiling of milk kefir beverage were performed as well as growth parameters, food intake, serum markers, oxidative stress, antioxidant enzymes, SCFAs, and metabarcoding were analyzed in the mice. Milk kefir had 76.64 ± 0.42% of free radical scavenging and the microbiota composed primarily by the genus Comamonas. Moreover, kefir increased catalase and superoxide dismutase (colon), and SCFAs in feces (butyrate), and in the brain (butyrate and propionate). Kefir reduced triglycerides, uric acid, and affected the microbiome of animals increasing fecal butyrate-producing bacteria (Lachnospiraceae and Lachnoclostridium). Our results on the brain and fecal SCFAs and the antioxidant effect found were associated with the change in the gut microbiota caused by kefir, which indicates that kefir positively influences the gut-microbiota-brain axis and contributes to the preservation of gut and brain health. Key points: • Milk kefir modulates fecal microbiota and SCFA production in brain and colon. • Kefir treatment increases the abundance of SCFA-producing bacteria. • Milk kefir increases antioxidant enzymes and influences the metabolism of mice. [ABSTRACT FROM AUTHOR]

Sheep farming is an important socioeconomic activity in most Mediterranean countries, particularly Spain, where it contributes added value to rural areas. Sheep milk is used in Spain mainly for making cheese, but it can be used also for making other dairy products, such as the lactic-alcoholic fermentation product known as kefir. Dairy products have health benefits because, among other reasons, they contain molecules with biological activity. In this work, we performed a proteomics strategy to identify the peptidome, i.e., the set of peptides contained in sheep milk kefir fermented for four different periods of time, aiming to understand changes in the pattern of digestion of milk proteins, as well as to identify potential bioactive peptides. In total, we identified 1942 peptides coming from 11 different proteins, and found that the unique peptides differed qualitatively among samples and their numbers increased along the fermentation time. These changes were supported by the increase in ethanol, lactic acid, and D-galactose concentrations, as well as proteolytic activity, as the fermentation progressed. By searching in databases, we found that 78 of the identified peptides, all belonging to caseins, had potential biological activity. Of these, 62 were not previously found in any milk kefir from other animal species. This is the first peptidomic study of sheep milk kefir comprising time-course comparison. [ABSTRACT FROM AUTHOR]

This paper aimed to evaluate the effect of a diet supplemented with fermented products on the meat quality of Siberian sturgeon (Acipenser baerii) reared in a recirculation aquaculture system. The fermented product was made by combining artisanal cultures of Kombucha and milk kefir granules grown up in sucrose, black tea, and bovine colostrum. Four experimental groups were established: V1 - a control group that received a commercial diet with 54% crude protein, and V2 to V4 groups, which received the same diet supplemented with 1 g/kg, 2 g/kg, and 3 g/kg of fermented product, respectively. After 35 days of diet administration, the biochemical composition of fresh meat was analysed. The results showed that the addition of fermented products significantly influenced the water, ash, and lipid content of A. baerii meat (p < 0.05), while the protein content was not influenced (p > 0.05) by the administrated diet. In conclusion, it is evident that adding the fermented product in A. baerii meat has an improving effect on body composition [ABSTRACT FROM AUTHOR]

Water kefir is a plant-based type of kefir and has significant differences from well-known milk kefir. Recently, various complicated substrates were fermented with water kefir grains, but an economical substrate is essential for the industrial aspect. This study aims to understand changes in fermentation products of water kefir grains during fermentation with economic substrates and investigates how fermentation progresses under almost ideal fermentation parameters. The fig-based medium provided high contents of Lactobacillus spp. and Lactococcus spp. Also, fig-based medium with high fructose content contained a higher amount of Bifidobacterium sp. Moreover, the fig-based medium resulted in more organic acid content, forming as much as ten times higher than the sugar-based medium for lactic acid after the same fermentation time (p < 0.05). On the other hand, volatile compounds such as acetaldehyde, ethyl acetate, ethanol, acetic acid, 2-ethyl-1-hexanol, oxime-, methoxy-phenyl, and phenylethyl alcohol were detected for both water kefir samples. Antioxidant capacity (TEAC and ORAC) was higher for the fig-based medium than for the sugar-based medium. This is the first study that comprehensively proved that only sugar solution was not a sufficient medium for water kefir fermentation, but fig containing solution had abundant nutrients to obtain preferable and acceptable water kefir beverage. [ABSTRACT FROM AUTHOR]

Cheese whey (CW) is the liquid by-product of cheese and yogurt making. This potential pollutant has high-quality nutrients exploitable through fermentation processes. Using high-intensity ultrasound on dairy products has shown several technological advantages for bioprocesses. Therefore, this study aimed to investigate the effect of high-intensity ultrasound (HIUS) on kefir grains biomass increase and specific metabolites in CW kefir. Fresh CW was ultrasonicated at 9.0 ± 2.7 and 18.0 ± 3.0 W/cm2 for 30 and 180 s, inoculated with kefir grains, and fermented for 40 h. Total exopolysaccharide production, kefir grains biomass increase, titratable acidity, pH, and soluble solids were analyzed every 8 h. CW pretreated with 18.0 ± 3.0 W/cm2 for 180 s and fermented for 16 h had significantly higher (p < 0.05) total exopolysaccharide concentration than the control: 212.7 ± 0.0 and 186.6 ± 0.0 mg/L, respectively. Ultrasonicated CW at 18 W/cm2 for 30 and 180 s at 24 h fermentation time had significantly higher kefir grains biomass (p < 0.05) than the control: 44.2 ± 0.8 and 43.6 ± 0.9 g/L, and 40.5 ± 0.4 g/L, respectively. Fresh CW pretreated with HIUS enhanced the biosynthesis of kefir beverage total exopolysaccharides concentration and kefir grains biomass. [ABSTRACT FROM AUTHOR]

Low-alcohol wines (ranging from <0.5 to 10.5% vol) are novel products that have been steadily gaining scientific and commercial attention. Over the past few years, consumer interest in healthier foods has augmented the development of novel functional products containing probiotic microorganisms, while the urge for a reduction in chemical preservatives has shifted the food and wine industry's interest to natural alternatives, such as essential oils (EOs). In the present study, low-alcohol (~6% vol) wines with (wet or dried) immobilized kefir cultures on fruit pieces, and essential oils (Citrus medica or Cinnamomum zeylanicum) were produced and evaluated for their properties. The viability of the immobilized kefir cultures on apple and pear pieces was not affected by the addition of EOs, and levels >7 logcfu/g were maintained after 2 h of immersion in wines. HS-SPME GC/MS analysis revealed characteristic compounds originating from the chemical composition of the added EOs in the final products. Principal component analysis (PCA) revealed that the relative content of terpenes, alcohols and carbonyl compounds played a major role in the discrimination of low-alcohol wine products. EO addition affected the products' sensory evaluation and resulted in significantly higher aroma and taste density compared to control samples. Notably, all novel Sangria-type wine variants were approved during preliminary sensory evaluation. [ABSTRACT FROM AUTHOR]

Prebiotic effects have been attributed to agave fructans through bacterial and yeast fermentations, but there are few reports on their use as raw materials of a carbon source. Kefir milk is a fermented drink with lactic acid bacteria and yeast that coexist in a symbiotic association. During fermentation, these microorganisms mainly consume lactose and produce a polymeric matrix called kefiran, which is an exopolysaccharide composed mainly of water-soluble glucogalactan, suitable for the development of bio-degradable films. Using the biomass of microorganisms and proteins together can be a sustainable and innovative source of biopolymers. In this investigation, the effects of lactose-free milk as a culture medium and the addition of other carbon sources (dextrose, fructose, galactose, lactose, inulin and fructans) in concentrations of 2, 4 and 6% w/w, coupled with initial parameters such as temperature (20, 25 and 30 °C), % of starter inoculum (2, 5 and 10% w/w) was evaluated. The method of response surface analysis was performed to determine the optimum biomass production conditions at the start of the experiment. The response surface method showed that a 2% inoculum and a temperature of 25 °C were the best parameters for fermentation. The addition of 6% w/w agave fructans in the culture medium favored the growth of biomass (75.94%) with respect to the lactose-free culture medium. An increase in fat (3.76%), ash (5.57%) and protein (7.12%) content was observed when adding agave fructans. There was an important change in the diversity of microorganisms with an absence of lactose. These compounds have the potential to be used as a carbon source in a medium culture to increase kefir granule biomass. There was an important change in the diversity of microorganisms with an absence of lactose, where the applied image digital analysis led to the identification of the morphological changes in the kefir granules through modification of the profile of such microorganisms. [ABSTRACT FROM AUTHOR]

Probiotic foods such as kefir drinks help to improve the health and well-being of consumers. Since Salmonella resistance to current antibiotic drugs is rising at an alarming rate worldwide, especially in Africa and Asia, this has raised the need for alternative ways of preventing and treating infectious diseases in humans and animals. Thus, a dairy-free probiotic drink can be an alternative for people with milk allergies or for those who avoid dairy products as a lifestyle choice. This study aims to optimize the quality of the coconut milk kefir drink for its antioxidant and antimicrobial activities and to identify the peptides and metabolites present. The time, temperature, and inoculum size that resulted in the optimal antioxidant and antimicrobial activities using Response Surface Methodology (RSM) were found to be 13.4 h, 25 °C, and 5.4 g/100 mL, respectively. The metabolic changes of coconut milk kefir at the beginning and end of fermentation were identified using 1H-NMR-based metabolomics. Some of the metabolites that were identified in the optimized product are γ-Aminobutyric acid, Biotin, Riboflavin, Butyrate, Lactate, and Caprylate. Moreover, 10 peptide sequences were identified using LC-MS/MS. The findings of this study demonstrated a high potential for coconut milk fermented using kefir grains as a functional healthy drink. [ABSTRACT FROM AUTHOR]

Fermented foods are an important diet component of people around the world. Kefir, or fermented milk, is popular worldwide due to its high nutritional value, with cow's milk being the common substrate for traditional kefir fermentation. However, the scarcity of animal-based milk in some countries, plus cultural, religious, and health reasons, have seen non-dairy milk kefir from almond milk gaining popularity among consumers globally. This study aimed to evaluate and compare the proximate composition and anti-microbial activity of kefir produced from 100% cow or 100% almond or an equal (1:1) mixture of both kinds of milk. This study used the AOAC 2000 method for the proximate analysis, while the agar well diffusion method examined the anti-microbial activity of the milk samples against Escherichia coli, Staphylococcus aureus, and Salmonella typhi. Results revealed that the three kefir samples showed significantly different (p<0.05) moisture, total dietary fiber, and fat contents and were within the CODEX acceptable range for kefir. All samples exhibited varying degrees of inhibition between the different pathogens. The diameters of the inhibition zone of the tested kefir samples were significantly different toward Salmonella typhi (p<0.05), with the mixture of almond and cow milk notably producing better inhibition towards all tested bacteria. The above-said milk mixture also gave a better overall nutrient profile (lower fat and higher fibre). While almond milk might be a suitable substrate for kefir, it was not effectively inhibitory for all bacteria. The overall results thus conveyed the promising use of almond and cow milk mixture as an alternative substrate for kefir fermentation, further supporting its potential use as a probiotics source. [ABSTRACT FROM AUTHOR]

Kefir is a fermented milk beverage different in consistency and taste from other popular milk-product yogurt. Unlike yogurt prepared using lactic acid bacteria in fermentation, milk is fermented for kefir production using preculture in the form of kefir grains. Therefore, the metabolic activities of a mixed culture, including strains of bacteria and yeast, contribute to the probiotic characteristics in kefir. This article is based on the review of published studies on the functionality and nutraceutical properties of kefir. The therapeutic and dietary properties of kefir beverage and its probiotic strains have been discussed for their several health benefits. Concise selected information mostly from recent reports has been presented for two categories of kefir products: milk used for the production of dairy-based traditional kefir beverages for the lactose-tolerant population, and the plant-sourced substrates used for the production of dairy-free kefir beverages for lactose-intolerant and vegan consumers. [ABSTRACT FROM AUTHOR]

Kefir is a traditional drink produced by the fermentation of milk with kefir grain. In this study, foam-mat drying of kefir using a microwave oven was made, and drying kinetics was determined at various microwave power levels (100, 180, and 300 W). Values of D eff were calculated between 4.8394 × 10 − 10 and 1.8603 × 10 − 9 m2 s-1. Besides, E a was calculated as 5.28 W g-1. Furthermore, increased drying rates were obtained with increasing microwave powers. In addition, seven drying models were fitted to the moisture ratios obtained from experiments, and Midilli and others' model was found to be the best-fitted model with the highest values (0.9983, 0.9983, and 0.9985 for 100, 180, and 300 W, respectively) of R 2 and the lowest values of χ 2 , RSS, and RMSE. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate essential traits of donkey's milk and cow's milk kefir during storage for 28 days at +4 °C. The results showed that the pH decreases significantly during fermentation from 6.75 ± 0.045 to 4.22 ± 0.062 for cow's milk and from 7.01 ± 0.011 to 4.28 ± 0.030 for donkey's milk. Acidity values increased significantly during storage from 63 ± 2.08 °D to 170 ± 2.80 °D for cow's milk and from 92 ± 1.0 °D to 163 ± 1.30 °D for donkey's milk (p < 0.05). A significant variation in total solids was observed during storage. Stability in protein content was observed for kefirs during storage time. While the level of lactose decreased significantly during storage, the fat content did not vary in kefirs during storage time at 4 °C. For microbiological properties, donkey milk kefir presents a significant difference (p < 0.05) compared to bovine kefir. Donkey's milk always contains the lowest average germs, suggesting a better microbiological quality than cow's milk samples. The fermented milks showed an interesting antioxidant activity measured by the DPPH and ABTS assays, which were improved during storage. The Aeromonas hydrophila was the most sensitive bacterium to the action of kefir samples. Results from the sensorial test show that participants prefer kefirs freshly prepared than those stored after 28 days at 4 °C. In conclusion, related to its unique bioactive activities and microbiological properties, donkey's milk could be an interesting kefir fermentation source materials alternative. [ABSTRACT FROM AUTHOR]

In this study, vegetable milk was produced from oilseeds of hazelnut, almond, peanut, walnut and cashew without additives and sugar. Vegetable milks were fermented using kefir starter culture. In addition to vegetable milk, kefir was also produced from cow's milk. The kefir samples were stored at 4°C for 30 days. The whey separation values, color parameters and the scores given by the panelists to evaluate the sensory properties of the samples were compared during the storage period. The highest serum separation value was determined in the kefir sample produced from walnut milk (18 ml), and the lowest serum separation value was determined in the kefir sample produced from peanut milk (1.16 ml). It was determined that the L, a, b, ΔE values and the color and appearance, structure and consistency scores given by the panelists decreased during storage, while the chroma, hue angle and whiteness index values and the taste and odor scores given by the panelists increased. In terms of general appreciation, kefir produced from hazelnut milk (3.76) was preferred the most, while kefir produced from cashew milk (2.46) was the least appreciated. [ABSTRACT FROM AUTHOR]

Goat milk kefir has high nutritional value, especially in protein and calcium content and has a low lactose content. Vacuum drying is an alternative to remove the water content in kefir so that it can extend the shelf life because it inhibits bacterial growth. This study determines the effect of aging time and drying time using vacuum drying method on the characteristics and amino acid composition of goat milk kefir (kefir and powder kefir). Fermented goat milk (24 hours) use kefir grains without aging and with aging times of 1, 2, 3, 4 (week). The total titrated acid and fat content were significantly different in kefir, but it is not significantly different in powder kefir. The yield, moisture, ash, protein, fiber, and fat in both kefir and powder kefir did not show significant differences. The best treatment based on the exponential comparison method for both powder kefir and kefir was 3 weeks of aging time. Therefore, the amino acid components in powder kefir and kefir underwent changes. The highest total amino acids in kefir was kefir without aging. The highest amino acid of powder kefir was obtained after 2 weeks of aging time. [ABSTRACT FROM AUTHOR]

Water kefir is a sparkling fermented beverage produced by fermenting water kefir grains in a sucrose solution containing dried fruits or fruit extracts. The objective of this study was to investigate the influence of substrate composition on the fermentation kinetics and culture-dependent microbial composition of water kefir. First, the impact of different fruit substrates and nitrogen limitation was examined. Fermentation of different fruit-based media with a single water kefir culture demonstrated that the substrate mainly influenced the type and ratio of the organic acids produced. These organic acid profiles could be linked to the culture-dependent microbial composition. In addition, the microbial composition and the associated dominant microorganisms observed were influenced by the water kefir fermentation conditions. Investigation of the effect of nitrogen limitation on the fermentation kinetics of several water kefir cultures showed that under such conditions, the fermentative capacity of the cultures declined. However, this decline was not immediate, and specific water kefir microorganisms may have enabled some cultures to maintain a higher fermentative capacity for longer. Thus, the water kefir fermentation kinetics and characteristics could be linked to the substrate composition, microorganisms present, and the process conditions under which the fermentations were performed. [ABSTRACT FROM AUTHOR]

Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) is a nomadic lactic acid bacterium (LAB) that inhabits a wide variety of ecological niches, from fermented foodstuffs to host-associated microenvironments. Many of the isolated L. paracasei strains have been used as single-strain probiotics or as part of a symbiotic consortium within formulations. The present study contributes to the exploration of different strains of L. paracasei derived from non-conventional isolation sources—the South African traditional fermented drink mahewu (strains MA2 and MA3) and kefir grains (strains KF1 and ABK). The performed microbiological, biochemical and genomic comparative analyses of the studied strains demonstrated correlation between properties of the strains and their isolation source, which suggests the presence of at least partial strain adaptation to the isolation environments. Additionally, for the studied strains, antagonistic activities against common pathogens and against each other were observed, and the ability to release bioactive peptides with antioxidant and angiotensin I-converting enzyme inhibitory (ACE-I) properties during milk fermentation was investigated. The obtained results may be useful for a deeper understanding of the nomadic lifestyle of L. paracasei and for the development of new starter cultures and probiotic preparations based on this LAB in the future. [ABSTRACT FROM AUTHOR]

The manufacture of fermented milk products has a long history, and these products were initially produced either from spontaneous fermentation or using a batch of previously produced product, that is, back-slopping. Milk of different mammal species has traditionally been used for the manufacture of fermented milk products. Cow's milk is the basis for most dairy fermented products around the world. Milk from other mammals, including sheep, goat, camel, mare, buffalo, and yak may have been historically more important and remain so in certain regions. The milks from different species have differences in chemical composition and in certain, vital for the fermentation, components. The diversity of fermented milk products is further influenced by the wide variety of manufacturing practices. A great number of fermented dairy products have been traditionally produced worldwide, and many of them are still produced either following the same traditional process or manufactured industrially, using standardized processes under controlled conditions with specified starter cultures. The evolution from traditional to industrial production, their specific regional differences, their special characteristics, and the microbiological aspects of fermented dairy products are discussed. Throughout the evolution of fermented milk products, functional and therapeutic properties have been attributed to certain components and thus, yogurts and fermented milks have gained a significant market share. These products have gained wide global recognition as they meet consumers' expectations for health-promoting and functional foods. The exploitation of microbiological methods based on DNA (or RNA) extraction and recently high-throughput techniques allowed for the accurate identification of the microbiota of fermented milk products. These techniques have revealed the significance of the properties of the autochthonous microbes and provided novel insights into the role of the microbiota in the functional and organoleptic properties of many fermented milk products. [ABSTRACT FROM AUTHOR]

In this study, a total of ten strains of kefir grains were isolated. Lactic acid bacteria and yeast were the research subjects. The final compound fermentation starter was produced using Leu. Mesenteroides, Lactobacillus kefir, Lactobacillus casei, and K. marxianus. The fermented milk of the compound fermentation starter and kefir grains were compared in curding time, acidity, water holding capacity (WHC), ethanol content, the viability of strains, and sensory score. The results showed that the quality of the fermented milk was similar, but the kinds of volatile aroma components in the kefir produced by the compound strain starter were significantly more than those of the kefir grains. The result of this study will help simplify and stabilize the industrial production of kefir, and provide a reference for the development of different flavored yogurt products. Novelty impact statement: The dominant kefir grain strains were divided to create the strain compound starter, which can be used in place of kefir grains. It can ferment and produce a milk drink with similar characteristics to traditional kefir grains. The dairy industry can develop using strain starters to overcome the limitations of kefir grains and produce kefir products with consistently high quality. [ABSTRACT FROM AUTHOR]

In this study, donkey milk and cow milk used for kefir production and the kefir samples were characterised based on compositional and microbiological properties, volatile aroma compounds, amino acid composition, and sensory analyses during storage for 21 days at 5 °C. Compared to cow milk kefir (CMK), donkey milk kefir (DMK) had lower contents of total solids, fat, and protein. Using donkey milk resulted in a weaker body characteristic in the kefir sample due to its low total solids content and the low ratio of casein. Acetaldehyde and acetic acid formation were at a remarkable level in DMK. Besides, the high lactose content of donkey milk caused more ethanol production in the kefir. Tyrosine, valine, and arginine were the primary amino acids in DMK. Donkey milk kefir was evaluated as acceptable in the aspect of sensorial properties such as taste and odour. Based on the present results, it could be concluded that a probiotic fermented beverage can be produced from donkey milk. [ABSTRACT FROM AUTHOR]

Numerous fruits are produced in Ecuador, of which about 40% are never eaten. In addition, fresh goat cheeses are in high demand. However, goat cheese generates goat milk whey with high contamination loads, and, therefore, it must be adequately treated before being discharged into ecosystems. This research aims to use a mixture of tree tomato, common strawberry juices, and goat's milk whey, to be statically fermented by milk and water kefir grains (WKG) for 48 h. For this, a dual mixture design of L-optimal response surface methodology was carried out to find the conditions that maximized all the responses evaluated (lactic-acid bacteria and yeasts concentrations and the overall acceptability assessed on a 7-point scale). Experiments were carried out in San Gabriel, Ecuador. Temperatures during the day and night were 20.2 ± 0.3 °C and 18.7 ± 0.3 °C, respectively. Three conditions were selected, where the highest response values were reached. Complementary experiments demonstrated the validity of the models. When comparing the results of the present study with similar ones carried out previously, higher values were observed in the concentration of yeasts, which seems related to the presence of the WKG. It is concluded that they could be suitable functional beverage candidates. [ABSTRACT FROM AUTHOR]

Summary: An innovative functional food with symbiotic and functional potential was produced by combining probiotic milk kefir, and white grape‐seed pomace obtained by UAE (ultrasound‐assisted extraction) rich in catechin and glycosylated flavonoids. The milk kefir was fortified by adding, after 24 h of fermentation, a polymer of inulin grafted with seed extract. The inulin/grape extract‐enriched polymer showed a higher antioxidant profile (P < 0.05). Simulated in vitro digestion demonstrated that 50 g of the kefir product would result in the delivery of antioxidants equivalent to 300 mg of ascorbic acid. The integrity of the intestinal barrier functions was not compromised by kefir treatments (at 10 μg mL‐1). [ABSTRACT FROM AUTHOR]

Based on the amino acid score (AAS), chemical score (CS), and amino acid proportional coefficient score (SRCAA) as evaluation indicators, millet powder, whey protein isolate powder, and soybean protein isolate powder were mixed to make millet compound powder. After the millet compound powder and water were uniformly mixed at a material‐to‐liquid ratio of 1:20, the kefir fermented millet nutritional milk was prepared by beating, gelatinizing, liquefying, saccharifying, and fermenting. The protein content, polyphenol content, viable count and acidity of kefir millet fermented milk were significantly higher than those of the other two commercially available similar beverages. The scavenging rates of DPPH free radicals and hydroxyl radicals in the kefir millet fermented milk group at three stages (before undigested, after gastric digestion for 2.5 h, and after intestinal digestion for 2.5 h) were significantly higher than those in the unfermented millet pulp group. Novelty impact statement: In this study, based on the amino acid pattern and amino acid nutrition evaluation methods (AAS, CS, SRCAA), millet flour and two protein powders with rich lysine content (whey protein isolate powder and soybean protein isolate powder) were rationally compounded as amino acid balanced millet compound powder. The millet compound powder is fermented by Lactobacillus kefir into millet nutritional fermented milk with unique flavor of probiotic fermentation. The antioxidant activity of millet nutritional fermented milk and millet pulp before fermentation was compared and analyzed by gastrointestinal digestion simulation in vitro, and it was determined that millet nutritional fermented milk had strong antioxidant activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The best flavors appeared on days 1–3 of fermentation in four kefirs. • Functional nutrients were largely increased after kefir fermentation. • Microbial changes were similar in Lactobacillus and Acetobacter in four kefirs. • GK and DK had more functional nutrients and higher microbial safety. • Fermentation patterns were similar for CoK and CaK, and for GK and DK. Kefir is a traditional dairy beverage, usually made from cow or goat milk fermented with kefir grains, and has many health benefits. To elucidate the fermentation patterns of animal milk kefirs during the fermentation process and find the optimal milk types, cow, camel, goat, and donkey milk were fermented with kefir grains for 0, 1, 3, 5, and 7 days. Volatile and non-volatile metabolites and microbial changes were dynamically monitored. The results showed that volatile flavor substances were massively elevated in four kefirs on days 1–3. Lipids and carbohydrates gradually decreased, while amino acids, small peptides, and tryptophan derivatives accumulated during fermentation in four kefirs. Besides, four kefirs had similar alterations in Lactobacillus and Acetobacter , while some distinctions existed in low-abundance bacteria. Association analysis of microorganisms and volatile and non-volatile metabolites also revealed the underlying fermentation mechanism. This study found that appropriately extending the fermentation time contributed to the accumulation of some functional nutrients. Furthermore, goat and donkey milk could be the better matrices for kefir fermentation. [ABSTRACT FROM AUTHOR]

The emergence of next-generation sequencing (NGS) technologies has revolutionized the way to investigate the microbial diversity in traditional fermentations. In the field of food microbial ecology, different NGS platforms have been used for community analysis, including 454 pyrosequencing from Roche, Illumina's instruments and Thermo Fisher's SOLiD/Ion Torrent sequencers. These recent platforms generate information about millions of rDNA amplicons in a single running, enabling accurate phylogenetic resolution of microbial taxa. This review provides a comprehensive overview of the application of NGS for microbiome analysis of traditional fermented milk products worldwide. Fermented milk products covered in this review include kefir, buttermilk, koumiss, dahi, kurut, airag, tarag, khoormog, lait caillé, and suero costeño. Lactobacillus—mainly represented by Lb. helveticus, Lb. kefiranofaciens, and Lb. delbrueckii—is the most important and frequent genus with 51 reported species. In general, dominant species detected by culturing were also identified by NGS. However, NGS studies have revealed a more complex bacterial diversity, with estimated 400-600 operational taxonomic units, comprising uncultivable microorganisms, sub-dominant populations, and late-growing species. This review explores the importance of these discoveries and address related topics on workflow, NGS platforms, and knowledge bioinformatics devoted to fermented milk products. The knowledge that has been gained is vital in improving the monitoring, manipulation, and safety of these traditional fermented foods. [ABSTRACT FROM AUTHOR]

This study aims to reveal the effect of each of prominent lactic acid bacteria (LAB) in the microbiota of kefir grain on the chemical and biochemical properties of kefir and especially, the formation of the volatile aroma compound (VAC) profile. Thus, fermented samples were produced in milk using single strains of Lactobacilluskefiranofaciens (LKF), Lentilactobacillusparakefiri (LP) and Lentilactobacilluskefiri (LK), as well as two control samples using kefir grain (TK) and commercial kefir culture (CK). In the samples, the change in LAB amounts, physicochemical (pH, titration acidity), rheological and chemical properties (organic acid, sugar and volatile flavour compound content) were investigated. The results showed no significant difference between LAB numbers and physicochemical properties of the samples. The LK, the LP and the LKF strains, respectively, were observed more activity in acetic acid production, citrate and lactose consumption. In VAC profiles, the LKF strain was associated with hexanol, 2-octanol, and octanal and LK with ethyl octanoate, ethyl hexanoate, acetaldehyde and geraniol. The LP strain was characterized by aldehydes including heptanal, nonanal and decanal. Thus, the L. parakefiri strain was highlighted in terms of the desired aroma profile. These results provide a clearer understanding of possible metabolic pathways and functions of the prominent strains in the kefir grain. [ABSTRACT FROM AUTHOR]

Kefir grains consist of complex symbiotic mixtures of bacteria and yeasts, and are reported to impart numerous health-boosting properties to milk and water kefir beverages. The objective of this work was to investigate the microbial communities in kefir grains, and explore the possibility of deriving useful probiotic strains from them. A total of 158 microbial strains, representing six fungal and 17 bacterial species, were isolated from milk and water kefir grains collected from a Singapore-based homebrewer. Based on 16S rRNA sequencing, isolated genera included Lactobacillus , Liquorilactobacillus , Lacticaseibacillus , Lentilactobacillus , Leuconostoc , Lactococcus , Acetobacter , Gluconobacter , Oenococcus , Clostridium , Zymomonas , Saccharomyces , Kluyveromyces , Pichia , Lachancea , Candida , and Brettanomyces. To characterize these isolates, a funnel approach, involving numerous phenotypic and genomic screening assays, was applied to identify kefir-derived microbial strains with the highest probiotic potential. Particular focus was placed on examining the pathogen inhibitory properties of kefir isolates toward enteric pathogens which pose a considerable global health burden. Enteric pathogens tested include species of Bacillus , Salmonella , Vibrio , Clostridium , Klebsiella , Escherichia , and Staphylococcus. Well diffusion assays were conducted to determine the propensity of kefir isolates to inhibit growth of enteric pathogens, and a competitive adhesion/exclusion assay was used to determine the ability of kefir isolates to out-compete or exclude attachment of enteric pathogens to Caco-2 cells. Seven bacterial strains of Lentilactobacillus hilgardii , Lacticaseibacillus paracasei , Liquorilactobacillus satsumensis , Lactobacillus helveticus , and Lentilactobacillus kefiri , were ultimately identified as potential probiotics, and combined to form a "kefir probiotics blend." Desirable probiotic characteristics, including good survival in acid and bile environments, bile salt hydrolase activity, antioxidant activity, non-cytotoxicity and high adhesion to Caco-2 cells, and a lack of virulence or antimicrobial resistance genes. In addition, vitamin and γ-aminobutyric acid (GABA) synthesis genes, were identified in these kefir isolates. Overall, probiotic candidates derived in this study are well-characterized strains with a good safety profile which can serve as novel agents to combat enteric diseases. These kefir-derived probiotics also add diversity to the existing repertoire of probiotic strains, and may provide consumers with alternative product formats to attain the health benefits of kefir. [ABSTRACT FROM AUTHOR]