Simulated Gastrointestinal Tract Conditions Research Articles

Orally ingestible medication utilizing layered double hydroxide nanoparticles strengthened alginate and hyaluronic acid-based hydrogel bead for bowel disease management

In the treatment of bowel diseases such as ulcerative colitis through oral administration, an effective drug delivery system targeting the colon is crucial for enhancing efficacy and minimizing side effects of therapeutic agents. This study focuses on the development of a novel nanocomposite hydrogel bead comprising a synergistic blend of biological macromolecules, namely sodium alginate (ALG) and hyaluronic acid (HA), reinforced with layered double hydroxide nanoparticles (LDHs) for the oral delivery of dual therapeutics. The synthesized hydrogel bead exhibits significantly enhanced gel strength and controllable release of methylprednisolone (MP) and curcumin (CUR), serving as an anti-inflammatory drug and a mucosal healing agent, compared to native ALG or ALG/HA hydrogel beads without LDHs. The physicochemical properties of the synthesized LDHs and hydrogel beads were characterized using various techniques, including scanning electron microscopy, zeta potential measurement, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. In vitro release studies of MP and CUR under simulated gastrointestinal tract (GIT) conditions demonstrate the superior controlled release property of the nanocomposite hydrogel bead, particularly in minimizing premature drug release in the upper GIT environment while sustaining release of over 82 % of drugs in the colonic environment. Thus, the modularly engineered carrier designed for oral colon targeting holds promise as a potential candidate for the treatment of ulcerative colitis.

Characterization of a symbiotic beverage based on water-soluble soybean extract fermented by Lactiplantibacillus plantarum ATCC 8014.

The health benefits of functional foods are associated with consumer interest and have supported the growth of the market for these types of foods, with emphasis on the development of new formulations based on plant extracts. Therefore, the present study aimed to characterize a symbiotic preparation based on water-soluble soy extract, supplemented with inulin and xylitol and fermented by Lactiplantibacillus plantarum ATCC 8014. Regarding nutritional issues, the symbiotic formulation can be considered a source of fiber (2g/100mL) and proteins (2.6g/100mL), and it also has a low-fat content and low caloric value. This formulation, in terms of microbiological aspects, remained adequate to legal standards after storage for 60days under refrigeration and also presented an adequate quantity of the aforementioned probiotic strain, corresponding to 9.11 Log CFU.mL-1. These viable L. plantarum cells proved to be resistant to simulated human gastrointestinal tract conditions, reaching the intestine at high cell concentrations of 7.95 Log CFU.mL-1 after 60days of refrigeration. Regarding sensory evaluation, the formulation showed good acceptance, presenting an average overall impression score of 6.98, 5.98, and 5.16, for control samples stored for 30 and 60days under refrigeration, respectively. These results demonstrate that water-soluble soy extract is a suitable matrix for fermentation involving L. plantarum ATCC 8014, supporting and providing data on the first steps towards the development of a symbiotic functional food, targeting consumers who have restrictions regarding the consumption of products of animal origin, diabetics, and individuals under calorie restrictions.

Characterization of Genomic, Physiological, and Probiotic Features of Lactiplantibacillus plantarum JS21 Strain Isolated from Traditional Fermented Jiangshui.

This study aimed to understand the genetic and metabolic traits of a Lactiplantibacillus plantarum JS21 strain and its probiotic abilities through laboratory tests and computer analysis. L. plantarum JS21 was isolated from a traditional fermented food known as "Jiangshui" in Hanzhong city. In this research, the complete genetic makeup of JS21 was determined using Illumina and PacBio technologies. The JS21 genome consisted of a 3.423 Mb circular chromosome and five plasmids. It was found to contain 3023 protein-coding genes, 16 tRNA genes, 64 rRNA operons, 40 non-coding RNA genes, 264 pseudogenes, and six CRISPR array regions. The GC content of the genome was 44.53%. Additionally, the genome harbored three complete prophages. The evolutionary relationship and the genome collinearity of JS21 were compared with other L. plantarum strains. The resistance genes identified in JS21 were inherent. Enzyme genes involved in the Embden-Meyerhof-Parnas (EMP) and phosphoketolase (PK) pathways were detected, indicating potential for facultative heterofermentative pathways. JS21 possessed bacteriocins plnE/plnF genes and genes for polyketide and terpenoid assembly, possibly contributing to its antibacterial properties against Escherichia coli (ATCC 25922), Escherichia coli (K88), Staphylococcus aureus (CMCC 26003), and Listeria monocytogenes (CICC 21635). Furthermore, JS21 carried genes for Na+/H+ antiporters, F0F1 ATPase, and other stress resistance genes, which may account for its ability to withstand simulated conditions of the human gastrointestinal tract in vitro. The high hydrophobicity of its cell surface suggested the potential for intestinal colonization. Overall, L. plantarum JS21 exhibited probiotic traits as evidenced by laboratory experiments and computational analysis, suggesting its suitability as a dietary supplement.

Assessment of safety and in situ antibacterial activity of Weissella cibaria strains isolated from dairy farms in Minas Gerais State, Brazil, for their food application.

Weissella cibaria W21, W25, and W42 strains have previously been characterized for their antagonism against a range of foodborne pathogens. However, prior to their use as protective agents, further analyses such as their safety and in situ activity are needed. The safety of W. cibaria W21, W25, and W42 strains was predicted in silico and confirmed experimentally. Analyses of their genomes using appropriate software did not reveal any acquired antimicrobial resistance genes, nor mobile genetic elements (MGEs). The survival of each strain was determined in vitro under conditions mimicking the gastrointestinal tract (GIT). Thus, hemolysis analysis was performed using blood agar and the cytotoxicity assay was determined using a mixture of two cell lines (80% of Caco-2 and 20% of HT-29). We also performed the inflammation and anti-inflammation capabilities of these strains using the promonocytic human cell line U937. The Weissella strains were found to be haemolysis-negative and non-cytotoxic and did not induce any inflammation. Furthermore, these strains adhered tightly to intestinal Caco-2 cell-lines and exerted in situ anti-proliferative activity against methicillin-resistant Staphylococcus aureus (strain MRSA S1) and Escherichia coli 181, a colistin-resistant strain. However, the W. cibaria strains showed low survival rate under simulated GIT conditions in vitro. The unusual LAB-strains W. cibaria strains W21, W25, and W42 are safe and endowed with potent antibacterial activities. These strains are therefore good candidates for industrial applications. The results of this study provide a characterization and insights into Weissella strains, which are considered unusual LAB, but which prompt a growing interest in their bio-functional properties and their potential industrial applications.

Isolation and characterization of novel Bacillus strains with superior probiotic potential: comparative analysis and safety evaluation

Despite the current use of some Bacillus spp. as probiotics, looking for and introducing new efficient and safe potential probiotic strains is one of the most important topics in both microbiology and food industry. This study aimed to isolate, identify, and evaluate the probiotic characteristics and safety of some Bacillus spp. from natural sources. Thirty-six spore-forming, Gram-positive, and catalase-positive Bacillus isolates were identified in 54 samples of soil, feces and dairy products. Bacterial identification was performed using 16S rDNA sequencing. To evaluate the probiotic potential of isolates, the resistance of bacterial cells to simulated gastrointestinal tract (GIT) conditions, the presence of enterotoxin genes, their susceptibility to antibiotics, antimicrobial and hemolytic activities and biochemical profiles were investigated. The results revealed that eight sporulating Bacillus spp. isolates fulfilled all tested probiotic criteria. They showed a high growth rate, non-hemolytic and lecithinase activity, and resistance to simulated GIT conditions. These strains exhibited broad-spectrum antibacterial activity against pathogenic bacteria. In addition, they did not exhibit antibacterial resistance to the 12 tested antibiotics. The results of this study suggest that these isolates can be considered as candidates for functional foods and as safe additives to improve diet quality.

Characterization of Lactococcus lactis 11/19-B1 Isolated from Kiwi Fruit as a Potential Probiotic and Paraprobiotic.

Probiotics are live bacteria used as food additives that are beneficial to human health. Lactococcus lactis 11/19-B1 strain isolated from kiwi fruit stimulates innate immunity in silkworms. Intake of yogurt containing the living 11/19-B1 strain significantly decreases the level of low-density lipoproteins (LDLs) in high-LDL volunteers and improves atopic dermatitis in humans. In this study, the probiotic properties of the 11/19-B1 strain, such as sensitivity to antimicrobial compounds, biogenic amine production, some virulence genes for human health, antimicrobial activity, tolerance to gastric acid and bile acids, and ability to adhere to the intestinal mucosa, were evaluated. The 11/19-B1 strain did not show resistance to the tested antimicrobial compounds except cefoxitin and fosfomycin. In addition, no production of amines that can harm humans, the antimicrobial activity required for probiotics, and the absence of adhesion to Caco-2 cells suggest that it is unlikely to attach to the intestinal epithelium. The 11/19-B1 strain grew in 0.3% but not in 1% bile salt. In the presence of 2% skim milk, the survival rate of the 11/19-B1 strain under simulated gastrointestinal tract conditions was 67% even after 4 h. These results indicate that the 11/19-B1 strain may function as a probiotic or paraprobiotic to be utilized in the food industry.

In vitro Survival of Microencapsulated Canine-Specific Probiotics Under Simulated Gastrointestinal Tract Conditions and During Storage

The survival of probiotics in the gastrointestinal system of dogs is crucial for them to provide health benefits. However, probiotics must also endure various physical conditions during commercial production and storage. Therefore, this study employed the microencapsulation technique to ensure the survival of probiotics using alginate as the encapsulation material, both alone and in combination with goat milk (alginate-goat milk). The study assessed the survival rates of two probiotic LAB strains, Enterococcus hirae Pom 4 and Ligilactobacillus animalis FB2, in both types of matrices under simulated dog gastrointestinal conditions, during food production, and 28 days of refrigeration at 4°C. The findings revealed that alginate-goat milk microcapsules had the highest encapsulation yield, and the viability of microencapsulated LAB cells in the alginate-goat milk matrix was the best protection for both probiotic strains under all conditions, including pasteurization temperature. Even after pasteurization, viable counts exceeding 6 log cfu/g were observed, indicating the promising application of alginate-goat milk microcapsules for optimal protection, enabling probiotics to survive until they reach the intended site and provide health benefits to dogs.

Bacteriocin and Antioxidant Production, a Beneficial Properties of Lactic Acid Bacteria Isolated from Fermented Vegetables of Northwest Bulgaria.

Lactiplantibacillus plantarum ST01BG, ST07BG, ST10BG, and ST15BG; Latilactobacillus curvatus ST02BG; Lacticaseibacillus paracasei ST04BG; Pediococcus pentosaceus ST05BG; Leuconostoc mesenteroides ST06BG; and Enterococcus faecium ST11BG were isolated from home-made fermented vegetables from Northwest Bulgaria and identified by biochemical, physiological, and biomolecular analyses, including partial 16S rRNA sequencing. The strains were designated as bacteriocin producers and the expressed antimicrobials partially characterized with a focus on their proteinaceous nature, stability to different pH and temperatures. The bacteriocins were effective in inhibiting different strains of Listeria spp., Enterococcus spp. (including vancomycin resistant enterococci) and Staphylococcus spp. These strains can be considered safe, based on the evaluation of hemolytic activity, production of biogenic amines, mucin degradation, antibiotic susceptibility/resistance, and gelatinase enzyme production. Moreover, the strains can be considered potentially beneficial based on their stability and survival under simulated gastrointestinal tract conditions (stomach and duodenum), the production of diacetyl, and specific levels of hydrophobicity. Special attention was given to antioxidant properties (DPPH radical, hydroxyl radical, superoxide anion radical scavenging activity, Fe+2 ion chelating activity, and anti-lipid peroxidation) of the strains. Antioxidant properties were found to be strain specific. The beneficial attributes (antimicrobial and antioxidant) of these cultures to fermented food products may enable the reduction of chemical additives in line with consumers' demand for more natural and chemical-free food commodities.

Isolation, functional activity, and safety of probiotics from Ethiopian traditional cereal-based fermented beverage, “Borde”

Yeast and lactic acid bacteria (LAB) were isolated from Ethiopian traditional fermented beverage, borde and evaluated for their potential probiotic properties, bile salt hydrolase (BSH) activity, cholesterol-lowering ability and antioxidant activity. Eleven LAB and thirteen yeast strains were selected based on their BSH activity and subjected for further examination. The results showed that LAB strains WS07, AM15, and AM20 exhibited a strong potential to lower cholesterol (85–90%), while yeast strains WS15, AA19, AM18, and AM23 showed the highest cholesterol removal (82–89%). All strains demonstrated strong antioxidant activity and survived simulated gastrointestinal tract (GIT) conditions. Four LAB and six yeast isolates were selected as the most promising probiotics based on their ability to resist simulated GIT environments. Safety evaluation revealed that none of the strains exhibited undesirable hemolytic activity or mucin hydrolysis. LAB strains were not resistant to most tested antibiotics except for vancomycin, gentamycin, and streptomycin, whereas yeast isolates were resistant to all antibiotics. The LAB strains WS07, AA13 and AM20, were identified as Pediococcus acidilactici, while, yeast isolates WS15 and AM18 were identified as Saccharomyces cerevisiae, and AA19 as Pichia cecembensis. Pediococcus acidilactici WS07 and Saccharomyces cerevisiae AM18 were identified as potential probiotic strains for cholesterol reduction.

Functional Characterization of Fermented Beverages Based on Soy Milk and Sea Buckthorn Powder.

Limitations of dairy products, such as lactose intolerance, problems related to a high cholesterol intake in diet, malabsorption, and the requirement for cold storage facilities, as well as an increasing demand for new foods and tastes, have initiated a trend in the development of non-dairy probiotic products. The possibility of producing beverages based on soy milk, sea buckthorn powder, and fermented by Bifidobacterium bifidus (Bb-12®, Bb) strain at different temperatures (30 °C and 37 °C) was examined. Strain viability, pH, and titratable acidity were measured during the fermentation period while the viability, pH, titratable acidity, and water holding capacity were determined during the storage time at 4 °C ± 1 °C within 14 days. Additionally, the survival and stability of Bb-12®, inoculated into a functional beverage when exposed to simulated gastrointestinal tract conditions, were assessed. The results obtained in this study revealed that the content of potent bioactive compounds in fermented soy milk and sea buckthorn powder depends on the processing conditions, the bacteria used in the fermentation step, and storage time.

Novel hydroxyectoines based formulations are suitable for preserving viability of Limosilactobacillus fermentum, Levilactobacillus brevis SP-48 and Bifidobacterium lactis HN019 during freeze-drying and storage, and in simulated gastrointestinal fluids

This study aimed at evaluating the influence of compatible solutes such as ectoine and hydroxyectoine (HOE), on bacterial cell viability during freeze-drying and storage (at 4 °C and 25 °C), in comparison to the well-established use of trehalose. Three strains, namely Limosilactobacillus fermentum, Levilactobacillus brevis SP-48, and Bifidobacterium lactis HN019 were used as models demonstrating that the highest survival rate during freeze drying was observed for cells protected with HOE. Although trehalose was more effective during lyophilization, interestingly the combination of trehalose and HOE most efficiently preserved long-term cell viability (viability loss < 0.5 log units after 6 months of storage). Finally, the ability of HOE to contribute to strain resistance in simulated gastrointestinal juices was evaluated and the latter protected all the strains tested more efficiently than all the other solutes, in particular the viability was improved from 58%, 87.5%, and 94% when cells were dried with saline solution to 88%, 98.3%, and 98% when lyophilized with HOE for L. fermentum, L. brevis, and B. lactis, respectively. In conclusion, the addition of HOE to trehalose improves the stability of probiotics during storage and enhances the survivability in simulated gastrointestinal tract conditions.

Probiotic potential of Saccharomyces cerevisiae GILA with alleviating intestinal inflammation in a dextran sulfate sodium induced colitis mouse model

Recently, several probiotic products have been developed; however, most probiotic applications focused on prokaryotic bacteria whereas eukaryotic probiotics have received little attention. Saccharomyces cerevisiae yeast strains are eukaryotes notable for their fermentation and functional food applications. The present study investigated the novel yeast strains isolated from Korean fermented beverages and examined their potential probiotic characteristics. We investigated seven strains among 100 isolates with probiotic characteristics further. The strains have capabilities such as auto-aggregation tendency, co-aggregation with a pathogen, hydrophobicity with n-hexadecane,1,1-diphenyl-2-picrylhydrazyl scavenging effect, survival in simulated gastrointestinal tract conditions and the adhesion ability of the strains to the Caco-2 cells. Furthermore, all the strains contained high cell wall glucan content, a polysaccharide with immunological effects. Internal transcribed spacer sequencing identified the Saccharomyces strains selected in the present study as probiotics. To examine the effects of alleviating inflammation in cells, nitric oxide generation in raw 264.7 cells with S. cerevisiae showed that S. cerevisiae GILA could be a potential probiotic strain able to alleviate inflammation. Three probiotics of S. cerevisiae GILA strains were chosen by in vivo screening with a dextran sulfate sodium-induced colitis murine model. In particular, GILA 118 down-regulates neutrophil–lymphocyte ratio and myeloperoxidase in mice treated with DSS. The expression levels of genes encoding tight junction proteins in the colon were upregulated, cytokine interleukin-10 was significantly increased, and tumor necrosis factor-α was reduced in the serum.

Screening of novel probiotics with intestinal peristalsis-promoting potential based on in vitro and in vivo investigations

Constipation is a widespread gastrointestinal issue. This work aimed to investigate anti-constipation capacities of 9 novel strains of Lactobacillus and Bifidobacterium using in vitro experiments for initial exploration and then further confirmed through in vivo models including both zebrafish and mice. The in vitro experimental results revealed that L. plantarum T34 and L. paracasei YJ10 could survive under the simulated gastrointestinal tract conditions as standard strain L. rhamnosus (LGG) did. L. paracasei YJ10 and L. casei Lc showed the highest 22 h's aggregation rate. L. rhamnosus W1 showed the highest coaggregation rate with E. coli and with S. aureus. T34 had the largest inhibition zones against S. typhimurium and L. Monocytogenes. The highest adhesion rates with HT-29 cells were L. casei Lc, LGG and W1. Principal component analysis (PCA) and Fuzzy synthetic evaluation (FSE) were performed to evaluate the in vitro probiotic potential of the 9 strains comprehensively. The order of scores on in vitro probiotic property from high to low was as follows: T34, W1, YJ10, Lc, LGG, SLT, SS, Lb, YN4 and LQSQ. The subsequent in vivo experiment of zebrafish further confirmed T34, W1 and YJ10 have better anti-constipation ability compared to other strains. Furthermore, T34 relieve loperamide-induced constipation by promoting gut transit in the mice model. In conclusion, T34 was demonstrated to prevent constipation and may be suggested for use in food and pharmaceutical goods.

Evaluation of the Probiotic Properties of Lacticaseibacillus casei 431® Isolated from Food for Special Medical Purposes§.

Increasing awareness of the importance of nutrition in health promotion and disease prevention has driven to the development of foods for special medical purposes (FSMPs). In this study, the probiotic strain Lacticaseibacillus paracasei ssp. paracasei (Lacticaseibacillus casei 431®) was incorporated into FSMPs to develop an innovative product. The aim was to investigate the influence of the FSMP matrix on the specific probiotic properties of L. casei 431® in vitro. A series of in vitro experiments were performed as part of the probiotic approach. After evaluation of antibiotic susceptibility profiles, functional properties such as survival under simulated gastrointestinal tract (GIT) conditions, bile salt deconjugation activities, cholesterol assimilation, antagonistic activity against spoilage bacteria and adhesion to Caco-2 cell line monolayers and extracellular matrix proteins were investigated. The L. casei 431® strain, both the lyophilised strain and the strain isolated from the FSMP matrix, effectively survived the simulated adverse gastrointestinal conditions without significant effects of the food matrix. The effect of the FSMP matrix on the deconjugation activity of the bile salts of L. casei 431® was minimal; however, cholesterol assimilation was increased by 16.4 %. L. casei 431® had antibacterial activity against related lactic acid bacteria regardless of whether it was used in FSMPs or not. Conversely, the probiotic strain isolated from FSMP matrix had significantly higher inhibitory activity against six potential pathogens than the lyophilised culture. The autoaggregation ability of the L. casei 431® cells was not affected by the FSMP matrix. The adhesion of L. casei 431® bacterial cells to the extracellular matrix proteins was reduced after treatment with proteinase K, with the highest adhesion observed to laminin. The adhesion of L. casei 431® reduced the binding of E. coli 3014 by 1.81 log units and the binding of S. Typhimurium FP1 to Caco-2 cell lines by 1.85 log units, suggesting the potential for competitive exclusion of these pathogens. The results support the positive effect of the FSMP matrix on the specific probiotic properties of L. casei 431®, such as antibacterial activity, bile salt deconjugation and cholesterol assimilation, while the incorporation of this probiotic strain adds functional value to the FSMPs. The synergistic effect achieved by the joint application of L. casei 431® and innovative FSMP matrix contributed to the development of the novel formulation of an improved functional food product with added value.

Nanobacterial Cellulose from Kombucha Fermentation as a Potential Protective Carrier of Lactobacillus plantarum under Simulated Gastrointestinal Tract Conditions.

Kombucha bacterial cellulose (KBC), a by-product of kombucha fermentation, can be used as a biomaterial for microbial immobilization. In this study, we investigated the properties of KBC produced from green tea kombucha fermentation on days 7, 14, and 30 and its potential as a protective carrier of Lactobacillus plantarum, a representative beneficial bacteria. The highest KBC yield (6.5%) was obtained on day 30. Scanning electron microscopy showed the development and changes in the fibrous structure of the KBC over time. They had crystallinity indices of 90-95%, crystallite sizes of 5.36-5.98 nm, and are identified as type I cellulose according to X-ray diffraction analysis. The 30-day KBC had the highest surface area of 19.91 m2/g, which was measured using the Brunauer-Emmett-Teller method. This was used to immobilize L. plantarum TISTR 541 cells using the adsorption-incubation method, by which 16.20 log CFU/g of immobilized cells was achieved. The amount of immobilized L. plantarum decreased to 7.98 log CFU/g after freeze-drying and to 2.94 log CFU/g after being exposed to simulated gastrointestinal tract conditions (HCl pH 2.0 and 0.3% bile salt), whereas the non-immobilized culture was not detected. This indicated its potential as a protective carrier to deliver beneficial bacteria to the gastrointestinal tract.

Screening and activity of potential gastrointestinal probiotic lactic acid bacteria against Yersinia ruckeri O1b.

Yersiniosis of cultured Atlantic salmon is a recurrent fish health management challenge in many continents. The causative organism, Yersinia ruckeri, can reside latently in the gut and lead to acute infection and disease during hatchery and sea-transfer stages. One potential prevention approach is the administration of probiotic bacteria to suppress gut colonization of Y. ruckeri. Our study aimed to isolate and identify anti-Yersinia activity among lactic acid bacteria (LAB) isolated from the gastrointestinal tract (GIT) of aquatic animals. Of the 186 aquatic GIT isolates examined, three strains showed diffusible antimicrobial activity towards Y. ruckeri O1b. Analysis of 16 s rRNA gene sequences indicated the three bacterial strains were Enterococci, related to Enterococcus sp. (99%), Enterococcus thailandicus (99%), and Enterococcus durans (99%). Anti-Yersinia activity was maintained at neutral pH (~6.5-7.0), and in-vitro environmental tolerance assays showed the three strains could withstand simulated salmonids gastrointestinal tract conditions of: low pH (3.4) and 3% bile salt content. All three Enterococci strains showed higher adhesion to the intestinal mucus of Atlantic salmon than Y. ruckeri O1b (E. durans 24%, E. enterococcus sp. 25% and E. thailandicus 98%, compared to Y. ruckeri O1b 5%). However, only Enterococcus sp. and E. thailandicus were able to grow in the salmon intestinal mucus broth while E. durans showed no growth. Anti-Yersinia activity was completely inactivated by proteinase-K treatment, suggesting that the active compound/s are proteinaceous and may be bacteriocin-like inhibitory substances (BLIS). Our data indicate that Enterococcus sp. MA176 and E. thailandicus MA122 are potential probionts for the prevention of yersiniosis in salmonids. Further in-vivo studies are required to determine whether these bacteria reduce the incidence of yersiniosis in Atlantic salmon.

Improving probiotic (Lactobacillus casei) viability by encapsulation in alginate-based microgels: Impact of polymeric and colloidal fillers

Biopolymer microgels (hydrogel beads) can be used to improve probiotic stability during food storage and gastrointestinal passage. In this study, the impact of including natural polymeric and colloidal fillers on the viability of Lactobacillus casei encapsulated in calcium alginate microgels was examined. The polymeric filler was polysaccharides isolated from Choerospondias axillaris fruit peel (CP) and the colloidal filler was oil-in-water emulsion stabilized by CP. Results showed that addition of CP or CP coated lipid droplets significantly increased the antioxidant activity but reduced the apparent viscosity of the alginate solutions. Encapsulation of the probiotics in pure calcium alginate microgels reduced their viability (≈0 log CFU g −1 after 24 h). The inclusion of the polymeric or colloidal fillers within the microgels eliminated this negative effect. Moreover, they enhanced probiotic viability under simulated gastrointestinal tract conditions (>7.0 log CFU g −1 ). The calcium alginate microgels containing CP had the highest probiotic viability (7.42 ± 0.08 log CFU g −1 ) after 20 days storage. Our results indicated that simple calcium alginate microgels are not effective at protecting Lactobacillus casei during storage or gastrointestinal passage. However, incorporation of suitable polymeric or colloidal fillers can significantly enhance their viability. • Microgels were formed by alginate and C. axillaris peel polysaccharides (CP). • Pure calcium alginate microgels encapsulation reduced probiotic viability. • Calcium alginate + CP microgels enhanced probiotic viability during storage. • Adding of CP or CP coated oil droplet improved probiotic gastrointestinal stability.

Probiotička karakterizacija soja Limosilactobacillus fermentum BGHV110 i njegov uticaj na urođeni imunski odgovor kod Caenorhabditis elegans

Probiotic lactobacilli exhibit the potential to promote health benefits for the host. Thanks to its numerous beneficial effects on human health, Limosilactobacillus fermentum stood out as an excellent candidate for the development of commercial probiotic preparations aiming to prevent community-acquired infections. In this study, several in vitro tests, including biofilm formation assay, assessment of antibiotic susceptibility, survival in simulated gastrointestinal tract conditions and attachment to intestinal Caco-2 cells, were used to estimate the safety and probiotic potential of L. fermentum BGHV110 strain. Additionally, Caenorhabditis elegans was used as an in vivo model system for the evaluation of L. fermentum BGHV110 influence on the host's innate immune response. The results revealed that L. fermentum BGHV110 strain showed an excellent capability to survive harsh conditions of the gut, to attach to intestinal Caco-2 cells and to stimulate conserved p38 MAPK immunity pathway and expression of the clc-1 claudin-like gene and antimicrobial peptides in C. elegans in order to enhance the immune response against pathogens. Finally, L. fermentum BGHV110 showed no virulence traits and susceptibility to tested antibiotics, confirming its safety status which enables it to be applied as a future probiotic.

Brewing and probiotic potential activity of wild yeasts Hanseniaspora uvarum PIT001, Pichia kluyveri LAR001 and Candida intermedia ORQ001

Non-conventional yeasts can be isolated from a wide range of environmental sources and are often found in the beverage industry in mixed fermentations, in which the microbial community is usually not fully known. However, it is important to know the compositions of these starter cultures because in addition to enabling reproducibility during fermentation, other properties can be discovered. Thus, the objective of this work was to identify and characterize non-conventional yeasts isolated from the environment, evaluating their probiotic potential and possible use in beer brewing. Isolates were obtained from flowers, fruits, leaves and mixed-fermentation beers, with the species being identified by PCR. Yeasts with promising activity were evaluated regarding their growth under different pHs, temperature and the presence of organic acids. To explore probiotic potential, in vitro tests were performed for antimicrobial activity and co-aggregation with food-spoiling microorganisms, auto-aggregation and survival in simulated gastrointestinal tract conditions. In this study, Pichia kluyveri (LAR001), Hanseniaspora uvarum (PIT001) and Candida intermedia (ORQ001) were selected among 20 isolates for further study. P. kluyveri was the only strain that tolerated pH 2.5. Lactic acid was not inhibitory, but acetic acid and incubation at 37 °C had partially inhibitory effects on yeast growth. All yeasts tolerated α-acids from hops and up to 1% NaCl. Our results also suggest that these isolates are able to adhere to intestinal cells and positively influence the host to combat pathogens, as they showed auto-aggregation rates > 99% and antagonistic activity to pathogenic bacteria. The yeasts tolerated gastric environment conditions, but were more sensitive to pancreatic conditions. We conclude that these non-conventional yeasts have probiotic potential and promising application in beer fermentation.

The thermal resistance and targeting release of zein-sodium alginate binary complexes as a vehicle for the oral delivery of riboflavin.

Riboflavin (RF) is one kind of vitamin B, which has low bioavailability due to the low water solubility and the high photosensitivity during food processing and storage. The anti-solvent precipitation method was applied to fabricate a zein-sodium alginate (SA) binary complexes delivery system with the loading of RF, which was aimed to enhance the delivery efficiency, stability, and controlled release of RF in the gastrointestinal (GI) tract. The formation mechanism, physicochemical properties as well as the digestion behaviors were investigated. The incorporation of SA significantly increased the diameter and decreased the surface positive charge of the nanoparticles. The surface morphology of the nanoparticles was characterized using the scanning electron microscope. The FTIR analysis revealed that the electrostatic attraction was the dominant binding force in the formation of the zein-SA binary complexes nanoparticles. In addition, the study on the in vitro release process showed that the zein-SA nanoparticles could delay the release of the RF under the simulated GI tract conditions, which improved their oral bioavailability. In summary, the zein-SA nanoparticle is an effective vehicle for the oral delivery of RF as well as other vitamins and bioactives in the applications of food and nutrition.