Microencapsulated Lactiplantibacillus plantarum ZGP-Lpl.19 modulates growth and virulence gene expression of Shigella flexneri ATCC 12022 in vitro.

Gamma-aminobutyric acid (GABA) production by free and Ca-alginate encapsulated cells of Enterococcus faecium CFR 3003 was investigated. Mass transfer rates characterizing the GABA production process using encapsulated cells were investigated. Experiments were performed to investigate external film and internal pore diffusion mass transfer rates. The Damkohler and Thiele analysis provides a good description of external film and internal pore diffusion resistances, respectively. The experiments revealed that the external film effects could be neglected but the process is affected to the greater extent by internal mass transfer effects and was found to be the principal rate-controlling step. Protective effect of encapsulation on cell survivability was tested under digestive environment, when challenged to salivary α-amylase, simulated gastric fluid and intestinal fluid. Viability of encapsulated cells was significantly higher under simulated gastro-intestinal conditions and could produce higher GABA than those observed with free cells. The results indicate that the Ca-alginate encapsulated probiotics could effectively be delivered to the colonic site for effective inhibitory action.

Breast milk is an important food for the neonates during their early months of development, primarily educating their immune system and protecting them for pathogens. The aim of this research was to investigate the probiotic properties (resistance to acid and bile salt) of free and microencapsulated Lb. rhamnosus LC705 strain isolated from mothers’ breast milk. Lb. rhamnosus LC705 was encapsulated into alginate (AL)-whey protein isolate (WPI) microspheres and morphology and particle size of the microcapsules were determined. The Viability of free and encapsulated forms in simulated gastric and intestinal juice was studied. Entrapment efficiency (emulsion method) was ~ 88%. The images of the scanning electron microscope (SEM) illustrated spherical shaped microcapsules with approximate diameters of less than 100 μm. The survival of free and microencapsulated Lb. rhamnosus LC705 was reduced to 6 and 4 log cycle in simulated gastric juice (pH 2.5, 2 h). Microencapsulated Lb. rhamnosus LC705 (D-values 27.10 min) survived better than the free cells (D-values 13.38 min) against bile salts (0.5%, 2 h). The survival of microencapsulated cells was significantly (p < 0.05) better than the free cells. Therefore microencapsulation of Lb. rhamnosus LC705 in AL–WPI containing matrix has the potential to increase the strain viability against simulated gastrointestinal conditions.

Survival of Ca-alginate microencapsulated Bifidobacterium spp. in milk and simulated gastrointestinal conditions

The core objective of the current study was to evaluate the effect of microencapsulation on the viability and stability of probiotic bacteria in yogurt and simulated gastrointestinal conditions. For this purpose, probiotic bacteria were encapsulated with sodium alginate and carrageenan by encapsulator. Yogurt was prepared with the incorporation of free and encapsulated probiotic bacteria and was analyzed for physicochemical, microbiological, and sensorial attributes. Encapsulation and storage exhibited a significant (p < .05) effect on different parameters of yogurt. An increasing trend in syneresis and acidity while a decreasing trend in viscosity, pH, viability, and stability were observed. The value of syneresis increased from 2.27 ± 0.17 to 2.9 ± 0.14 and acidity from 0.48 ± 0.04 to 0.64 ± 0.01 during 4 weeks of storage. The value of viscosity decreased from 3.68 ± 0.21 to 2.42 ± 0.09 and pH from 4.88 ± 0.31to 4.43 ± 0.36 during 28 days of storage. Unencapsulated (free) cells exhibited poor survival. The viable cell count of probiotic bacteria in the free‐state in yogurt was 9.97 logs CFU/ml at zero‐day that decreased to 6.12 log CFU/ml after 28 days. However, encapsulation improved the viability of the probiotics in the prepared yogurt and GIT. The cell count of probiotics encapsulated with sodium alginate and carrageenan was 9.91 logs CFU/ml and 9.89 logs CFU/ml, respectively, at zero‐day that decreased to 8.74 logs CFU/ml and 8.39 log CFU/ml, respectively. Free cells (unencapsulated) showed very poor survival. Similarly, during in vitro gastrointestinal assay, the survival rate of encapsulated probiotic bacteria in simulated gastric solution and intestinal solutions was higher than that of free cells. In the case of encapsulated bacteria, only 3 logs while for free cells, 7 log reduction was recorded. Sodium alginate microcapsules exhibited better release profile than carrageenan. Conclusively, microencapsulation improved the survival of probiotic bacteria in carrier food as well as in simulated gastrointestinal condition.

Stability of human salivary extracellular vesicles containing dipeptidyl peptidase IV under simulated gastrointestinal tract conditions

Viability of Lactobacillus plantarum NCIMB 8826 immobilized in a cereal-legume complementary food “weanimix” with simulated gastrointestinal conditions

In the current study, apple-pectin-based novel nanofibers were fabricated by electrospinning. Polyvinyl alcohol (PVA) and apple pectin (PEC) solution were mixed to obtain an optimized ratio for the preparation of electrospun nanofibers. The obtained nanofibers were characterized for their physiochemical, mechanical and thermal properties. The nanofibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). Furthermore, an assay of the in vitro viability of free and encapsulated probiotics was carried out under simulated gastrointestinal conditions. The results of TGA revealed that the PVA/PEC nanofibers had good thermal stability. The probiotics encapsulated by electrospinning showed a high survival rate as compared to free cells under simulated gastrointestinal conditions. Furthermore, encapsulated probiotics and free cells showed a 3 log (cfu/mL) and 10 log (cfu/mL) reduction, respectively, from 30 to 120 min of simulated digestion. These findings indicate that the PVA/PEC-based nanofibers have good barrier properties and could potentially be used for the improved viability of probiotics under simulated gastrointestinal conditions and in the development of functional foods.

BackgroundThe success of the probiotics in delivery of health benefits depends on their ability to withstand the technological and gastrointestinal conditions; hence development of robust cultures is critical to the probiotic industry. Combinations of probiotic cultures have proven to be more effective than the use of single cultures for treatment and prevention of heterogeneous diseases. We investigated the effect of pre- adaptation of probiotics to multiple stresses on their stability under simulated gastrointestinal conditions and the effect of their singular as well as their synergistic antagonistic effect against selected enteric pathogens.MethodsProbiotic cultures were inoculated into MRS broth adjusted to pH 2 and incubated for 2 h at 37°C. Survivors of pH 2 were subcultured into 2% bile acid for 1 h at 37°C. Cells that showed growth after exposure to 2% bile acid for 1 h were finally inoculated in fresh MRS broth and incubated at 55°C for 2 h. The cells surviving were then used as stress adapted cultures. The adapted cultures were exposed to simulated gastrointestinal conditions and their non- adapted counterparts were used to compare the effects of stress adaptation. The combination cultures were tested for their antipathogenic effects on Escherichia coli and Staphylococcus aureus.ResultsAcid and bile tolerances of most of the stress-adapted cells were higher than of the non-adapted cells. Viable counts of all the stress-adapted lactobacilli and Bifidobacterium longum LMG 13197 were higher after sequential exposure to simulated gastric and intestinal fluids. However, for B. longum Bb46 and B. bifidum LMG 13197, viability of non-adapted cells was higher than for adapted cells after exposure to these fluids. A cocktail containing L. plantarum + B. longum Bb46 + B. longum LMG 13197 best inhibited S. aureus while E. coli was best inhibited by a combination containing L. acidophilus La14 150B + B. longum Bb46 + B. bifidum LMG 11041. A cocktail containing the six non- adapted cultures was the least effective in inhibiting the pathogens.ConclusionMulti-stress pre-adaptation enhances viability of probiotics under simulated gastrointestinal conditions; and formulations containing a mixture of multi stress-adapted cells exhibits enhanced synergistic effects against foodborne pathogens.

Microplastics are prevalent in the environment and have a strong affinity to pollutants owing to their large specific surface area and hydrophobicity. Once ingested, microplastics transport pollutants into organisms. This study investigated bisphenol A (BPA) desorption behavior from three microplastic materials, namely, polystyrene (PS), polypropylene (PP), and polyamide (PA), under simulated biological gastrointestinal conditions. The results showed that BPA can rapidly desorb from microplastic carriers under simulated gastrointestinal conditions, with different BPA desorption percentages in the order of PP &amp;gt; PS &amp;gt; PA. This was related to the amorphous structure and functional groups of the polymers. The BPA desorption behavior of microplastics in gastric juices was not significantly affected by pH; however, within the pH range of intestinal juices, the BPA desorption percentage increased significantly as the pH increased. The increase in Na+ concentration in the gastrointestinal tract exhibited a certain inhibitory effect on BPA desorption from microplastics owing to the salting-out effect. The temperature of digestive juices positively affected BPA desorption, suggesting that endothermic organisms are more susceptible to it. Our findings help elucidate the potential health risks of exposure to microplastics and their sorbed pollutants in the environment.

Postbiotic characterization of a potential probiotic yeast isolate, and its microencapsulation in alginate beads coated layer-by-layer with chitosan

Encapsulation of Bifidobacterium longum in alginate-dairy matrices and survival in simulated gastrointestinal conditions, refrigeration, cow milk and goat milk

Microencapsulation as one of the most modern methods has considerable effects on probiotic survival. In this study Lactobacillus casei (ATCC 39392) and Bifidobacterium bifidum (ATCC 29521) were encapsulated using calcium alginate-gelatinized starch, chitosan coating and inulin via emulsion technique, and were incubated in simulated gastric juice (along with pepsin, pH=1.5) and simulated intestinal juice (along with pancreatin and bile salts, pH = 8) for 2 hours at 37 (o)C. The morphology and size of microcapsules were measured by scanning electron and optical microscopy. The results indicated that the survival of microencapsulated probiotic increased significantly in simulated gastro-intestinal condition (P < 0.05). Chitosan coating played a significant role in the protection of probiotic bacteria in simulated gastro-intestinal condition and the diameter of the microcapsules increased with the addition of chitosan coating. In general, this study indicated that microencapsulation with alginate-gelatinized starch coated with chitosan could successfully and significantly protect probiotic bacteria against adverse condition of simulated human gastro-intestinal condition.

The objective of this work was to explore the effect of two encapsulating polysaccharides (sodium alginate and carrageenan) on the viability of probiotic bacteria (L. acidophilus) in ice cream and under simulated gastrointestinal (GIT) conditions. For the purpose, probiotic cells were encapsulated in sodium alginate and carrageenan by an encapsulator using standard operating conditions. Ice cream was manufactured by adding free and microencapsulated probiotics. The survival of free and encapsulated probiotics was monitored over a period of 120days at - 20°C. Furthermore, the survival of free and encapsulated probiotic bacteria under the simulated GIT conditions was investigated. The results of the study showed that encapsulation significantly (p < 0.05) improved the cell survival of probiotics in ice cream compared to free cells (non-encapsulated). The viable cell count of probiotic bacteria in the free-state in ice cream was 9.97log cfu/ml at 0 day that decreased to 6.12logcfu/ml after 120days. However, encapsulation improved the viability of the probiotics in the prepared ice cream and GIT. The cell count of probiotics encapsulated with sodium alginate and carrageenan was 9.91logcfu/ml and 9.89logcfu/ml respectively at 0 day that decreased to 8.74logcfu/ml and 8.39logcfu/ml respectively after 120days. Similarly, during simulated gastrointestinal assay, the survival rate of encapsulated probiotic bacteria in simulated gastric solution and intestinal solutions was higher than that of free cells. In the case of encapsulated bacteria, only three log while for free cells seven log reduction was recorded. Sodium alginate microcapsules exhibited better release profile than carrageenan. Conclusively, the incorporation of encapsulated probiotics had a significant effect on quality parameters and sensorial characteristics of ice cream.

This study aimed to evaluate the physicochemical, structural, antioxidant and antibacterial properties of chitosan-coated (0.5 and 1% CH) nanoliposomes containing hydrolyzed protein of Spirulina platensis and its stability in simulated gastric and intestine fluids. The chitosan coating of nanoliposomes containing Spirulina platensis hydrolyzed proteins increased their size and zeta potential. The fourier transform infrared spectroscopy (FT-IR) test showed an effective interaction between the hydrolyzed protein, the nanoliposome, and the chitosan coating. Increasing the concentration of hydrolyzed protein and the percentage of chitosan coating neutralized the decreasing effect of microencapsulation on the antioxidant activity of peptides. Chitosan coating (1%) resulted in improved stability of size, zeta potential, and poly dispersity index (PDI) of nanoliposomes, and lowered the release of the hydrolyzed Spirulina platensis protein from nanoliposomes. Increasing the percentage of chitosan coating neutralized the decrease in antibacterial properties of nanoliposomes containing hydrolyzed proteins. This study showed that 1% chitosan-coated nanoliposomes can protect Spirulina platensis hydrolyzed proteins and maintain their antioxidant and antibacterial activities.

The preadaptation of probiotics to sub-lethal levels of multiple stress factors boosts their survival and stability. However, little is known about how long-term cold storage affects the properties of such preadapted probiotics. This study examined the impact of long-term freezing on structural and functional properties of multi-stress (acid, bile and heat) adapted Lactiplantibacillus plantarum B411. Cell morphology was investigated using scanning electron microscopy, and then their selected functional (bile salt hydrolase (BSH) activity, surface hydrophobicity, auto-aggregative and antimicrobial) properties were evaluated. Furthermore, the survival of L. plantarum B411 cells in yoghurt and juices during storage and under simulated gastrointestinal (GIT) conditions was evaluated. Long-term freezing negatively affected the morphology, auto-aggregation ability, BSH and antimicrobial activities of L. plantarum B411. The viability of freshly adapted and old adapted L. plantarum B411 cells in foods was similar. Under simulated GIT conditions, the viability of the stress adapted cells from the freezer diminished more than that of freshly adapted cells. Prolonged freezing compromised some functional properties of stress adapted cells and their stability under simulated GIT conditions. Care should thus be taken to ensure that a method used to preserve stress adapted cells does not cause them to lose beneficial properties, nor revert to their pre-adaptation status.