Survival of Microencapsulated Probiotic Bacteria after Processing and during Storage: A Review

Safety and Efficacy of Probiotic Supplementation in Reducing the Incidence of Infections and Modulating Inflammation in the Elderly with Feeding Tubes: A Pilot, Double-Blind, Placebo-Controlled Study, "IntegPRO"

A double-blind, placebo-controlled study was performed in a sample of geriatric patients treated with home enteral nutrition (HEN) to analyze the efficacy of a probiotic supplement Proxian^®, which contains Lactiplantibacillus plantarum LP01 (LMG P-21021), Lentilactobacillus buchneri Lb26 (DSM 16341), Bifidobacterium animalis subsp. lactis BS01 (LMG P-21384), and is enriched with zinc (Zn) and selenium (Se), in reducing the incidence of infections and modulating inflammation. Thirty-two subjects were enrolled (mean age 79.7 ± 10.3 years), 16 in the intervention group, 16 controls. They received Proxian^® or placebo for 60 days. Patients were assessed at baseline (t₀) and 60 (t₁) and 90 (t₂) days after the beginning. Infections were detected by information regarding their clinical manifestations and the incidence of antibiotic therapy. Levels of C-reactive protein (CRP) were measured to study inflammation. Information on bowel function, nutritional status and testimonials regarding the feasibility of administration of the product were collected. Differences between the two groups in number of infections (25% intervention group vs. 44% controls), antibiotic therapies (12% vs. 37%) and modulation of CRP levels (median CRP moved from 0.95 mg/L (t₀)_, to 0.6 (t₁) and 0.7 (t₂) in intervention group vs. 0.7 mg/L, 0.5 and 0.7 in controls) did not reach statistical significance. No significant changes in bowel function and nutritional status were found. Caregivers’ adherence was 100%. Results of this “IntegPRO” study showed that Proxian^® is potentially safe, easy to administer and promising for further studies but it appears not to change the incidence of infections or modulate inflammation in elderly treated with HEN. The utility of Proxian^® in reducing the incidence of infections and modulating inflammation in these subjects needs to be investigated by a larger multi-center clinical trial, and by using additional analyses on inflammatory markers and markers of infections.

Survival and Goat Milk Acidifying Activity of Lactobacillus rhamnosus GG Encapsulated with Agave Fructans in a Buttermilk Protein Matrix

Lactobacillus rhamnosus GG (L. rhamnosus GG) cells were encapsulated in buttermilk proteins by spray drying, alone (E), or with Agave tequilana fructans (CEF). Buttermilk proteins acted as a thermo-protector for the probiotic cells undergoing the spray-dried process. The addition of Agave fructans in CEF microcapsules significantly enhanced storage stability and survival to in vitro simulated gastrointestinal conditions, compared to E capsules. After 14 days storage at - 20 °C, the number of living cells in CEF microcapsules was in the order of 7.7 log CFU • mL^-1 and the survivability in simulated gastrointestinal environment was 73.23%. Spray-dried microparticles were cultured in goat milk to study biomass production. Agave fructans offered a favorable microenvironment and better growth substrate. The population of CEF viable cells reached 1.08 ± 0.02 × 10¹⁰ CFU • mL^-1 after 18 h of fermentation. In contrast, the population of E viable cells were 3.0 ± 0.01 × 10⁹ CFU • mL^-1. The generation time of CEF, L. rhamnosus GG was 15% faster than E, L. rhamnosus GG. Encapsulation with buttermilk proteins in the presence of Agave fructans by spray drying could be suitable for preservation of probiotic powders and may be for a more effective application of probiotics in goat dairy products.

Influence of freezing temperature before freeze-drying on the viability of various Lactobacillus plantarum strains

Although freeze-drying is an excellent method for preserving microorganisms, it inevitably reduces cell activity and function. Moreover, probiotic strains differ in terms of their sensitivity to the freeze-drying process. Therefore, it is necessary to optimize the variables relevant to this process. The pre-freezing temperature is a critical parameter of the freeze-drying process, but it remains unclear whether the optimal pre-freezing temperature differs among strains and protectants. This study explored the effects of 4 different pre-freezing temperatures on the survival rates of different Lactobacillus plantarum strains after freeze-drying in the presence of different protectants. Using phosphate-buffered saline solution and sorbitol as protectants, pre-freezing at -196°C, -40°C, and -20°C ensured the highest survival rates after freeze-drying for AR113, AR307, and WCFS1, respectively. Using trehalose, pre-freezing at -20°C ensured the best survival rate for AR113, and -60°C was the best pre-freezing temperature for AR307 and WCFS1. These results indicate that the pre-freezing temperature can be changed to improve the survival rate of L. plantarum, and that this effect is strain-specific. Further studies have demonstrated that pre-freezing temperature affected viability via changes in cell membrane integrity, membrane permeability, and lactate dehydrogenase activity. In summary, pre-freezing temperature is a crucial factor in L. plantarum survival after freeze-drying, and the choice of pre-freezing temperature depends on the strain and the protectant.

Probiotic powders prepared by mixing suspension of Lactobacillus salivarius NRRL B-30514 and spray-dried lactose: Physical and microbiological properties

Preparation of powdered probiotics is important for storage and application. In this work, a novel method to prepare powdered probiotic ingredients was studied by mixing a Lactobacillus salivarius NRRL B-30514 suspension with amorphous spray-dried lactose at suspension: lactose (v:w) ratios (SLR) of 1:5, 1:15, and 1:25. The simple procedure resulted in lactose-probiotics powders (LPPs) with greater probiotic viability initially and during subsequent 6-month storage at a smaller SLR. In LPPs with SLRs of 1:5 and 1:15, X-ray diffraction spectroscopy and scanning electron microscopy results indicated the formation of lactose crystals, and BacLight® assay suggested the significantly lowered membrane integrity of probiotics due to hypertonic pressure of lactose dissolved in excessive water. A viable but non-culturable state of L. salivarius in LPPs may exist based on the BacLight® and CTC reduction assays. The present study may provide a novel approach to prepare powdered probiotic ingredients.

The Combined Usage of β-Cyclodextrin and Milk Proteins in Microencapsulation of Bifidobacterium bifidum BB-12

The present study aimed to determine the effects of combined usage of β-cyclodextrin with whey protein isolate and sodium caseinate on the microencapsulation of Bifidobacterium bifidum-BB12 by spray drying.From the results, the highest count of B. bifidum was provided by whey protein isolate as 8.62 log CFU/g. The increasing concentration of β-cyclodextrin considerably increases gastric and intestinal resistance to B. bifidum cells. In the gastric and intestinal test, the highest protection was determined in whey protein isolate substituted with 10% β-cyclodextrin with reduction rates of 0.98 and 3.30%, respectively. Moreover, free cells did not survive in the same gastric conditions. The lowest hygroscopicity was determined in whey protein isolate as 8.57%. It must be noted that increasing β-cyclodextrin concentration in carrier material combination led to an increase in hygroscopicity of microcapsules. In general, substitution with β-cyclodextrin increased the particle size of microparticles, and microcapsules produced with whey protein isolate had a smaller size than that of sodium caseinate.

Delivery to the gut microbiota: A rapidly proliferating research field

The post genomic era has brought breakthroughs in our understanding of the complex and fascinating symbiosis we have with our co-evolving microbiota, and its dramatic impact on our physiology, physical and mental health, mood, interpersonal communication, and more. This fast "proliferating" knowledge, particularly related to the gut microbiota, is leading to the development of numerous technologies aimed to promote our health via prudent modulation of our gut microbiota. This review embarks on a journey through the gastrointestinal tract from a biomaterial science and engineering perspective, and focusses on the various state-of-the-art approaches proposed in research institutes and those already used in various industries and clinics, for delivery to the gut microbiota, with emphasis on the latest developments published within the last 5 years. Current and possible future trends are discussed. It seems that future development will progress toward more personalized solutions, combining high throughput diagnostic omic methods, and precision interventions.

Low-moisture food matrices as probiotic carriers

To exert a beneficial effect on the host, adequate doses of probiotics must be administered and maintaining their viability until consumption is thus essential. Dehydrated probiotics exhibit enhanced long-term viability and can be incorporated into low-moisture food matrices, which also possess high stability at refrigeration and ambient temperature. However, several factors associated with the desiccation process, the physicochemical properties of the matrix and the storage conditions can affect probiotic survival. In the near future, an increased demand for probiotics based on functionally dominant members of the gut microbiome ('next-generation probiotics', NGP) is expected. NGPs are very sensitive to oxygen and efficient encapsulation protocols are needed. Strategies to improve the viability of traditional probiotics and particularly of NGPs involve the selection of a suitable carrier as well as proper desiccation and protection techniques. Dehydrated probiotic microcapsules may constitute an alternative to improve the microbial viability during not only storage but also upper gastrointestinal tract passage. Here we review the main dehydration techniques that are applied in the industry as well as the potential stresses associated with the desiccation process and storage. Finally, low- or intermediate-moisture food matrices suitable as carriers of traditional as well as NGPs will be discussed.

Evaluation of probiotic Bacillus coagulans MTCC 5856 viability after tea and coffee brewing and its growth in GIT hostile environment

In recent years, probiotic functional foods have gained quite a popularity and become a preferred choice among consumers, due to their positive effects on the gut microbiota and overall health. However, it is imperative for a probiotic strain to remain live and active at the time of consumption in high enough population density, in order to provide such health benefits. Thus, this study aimed to investigate the Bacillus coagulans MTCC 5856 spore stability after tea and coffee brewing and its subsequent growth in gastrointestinal tract (GIT) hostile environment. B. coagulans MTCC 5856 showed remarkable survival (94.94% and 99.76% in unroasted green coffee and tea, respectively) after brewing conditions and was able to grow in GIT hostile conditions using tea and coffee as a sole nutritional source. B. coagulans MTCC 5856 inclusion in tea and coffee after brewing did not significantly (P > .05) alter the sensory profile when compared to that without the probiotic inclusion. Moreover, B. coagulans MTCC 5856 growth was significantly (P < .05) higher when water soluble fibers were added during brewing, suggesting a synergistic property. It showed over 99% viability (P > .05) in tea and coffee powder at room temperature up to 24 months of storage. This study demonstrated the stability of the tested probiotic strain B. coagulans MTCC 5856 after tea and coffee brewing and its growth in GIT hostile environment, thereby suggesting functional probiotic use in tea and coffee.

Multifunctional Role of the Whey Culture Medium in the Spray Drying Microencapsulation of Lactic Acid Bacteria

This study aims to evaluate the multifunctional role of whey culture medium during the spray drying microencapsulation of Lactobacillus fermentum K73. Whey culture medium containing growing microorganisms served to hydrate different mixtures (gum arabic, maltodextrin and whey). We evaluated the use of these mixtures as carbon sources and their protective effects on simulated gastrointestinal conditions. The optimal mixture was spray-dried while varying the outlet temperature and atomizing pressure using a response surface design. These conditions served to evaluate microorganism survival, tolerance to gastrointestinal conditions in vitro, physicochemical properties, morphometric features and stability at 4, 25 and 37 °C. Lactobacillus fermentum K73 replicated in the carrier material. Bacterial change cycles were (-1.97±0.16) log CFU/g after the drying process and 
(-0.61±0.08) and (-0.23±0.00) log CFU/g after exposure of the capsules to simulated gastric pH and bile salt content, respectively. The physicochemical properties and morphometric features were within the normal ranges for a powder product. The powder was stable at a storage temperature of 4 °C. The spray drying of the whey culture medium with growing microorganisms using the optimized drying conditions was successful. This study demonstrates the use of whey culture medium as a component of carrier material or as the carrier material itself, as well as its protective effects during drying, under simulated gastrointestinal conditions, and at varied storage temperatures.

Ambient storage of microencapsulated Lactobacillus plantarum ST-III by complex coacervation of type-A gelatin and gum arabic

Ambient storage of dry powdered probiotics is necessary for manufacturer's cost reduction and customer's convenience. Complex coacervation is a promising microencapsulation technique. In this work, a probiotic matrix of type-A gelatin/gum arabic/sucrose (GE/GA/S) with high coacervation pH was designed, based on the alkaline isoelectric point of type-A gelatin. Bacterial survival during ambient storage at room temperature and certain relative humidity were detected. To clarify the protection factors of the coacervation matrix of GE/GA/S, dry microcapsules of GA, GE, GE/sucrose and GE/GA were prepared as controls and compared in terms of their morphology, moisture content, dynamic vapor absorption and cell viability. Probiotics in GE/GA/S_5.5 microcapsules behaved the best during spray drying, ambient storage and heat treatment. The results proved that sucrose addition was necessary for cell viability against environmental stresses, and that encapsulation by complex coacervation was a positive factor in cell protection, especially at neutral coacervation pH.

Statistical optimization of bambara groundnut protein isolate-alginate matrix systems on survival of encapsulated Lactobacillus rhamnosus GG

Encapsulation may protect viable probiotic cells. This study aims at the evaluation of a bambara groundnut protein isolate (BGPI)-alginate matrix designed for encapsulating a probiotic Lactobacillus rhamnosus GG. The response surface methodology was employed to gain the optimal concentrations of BGPI and alginate on encapsulation efficiency and survival of encapsulated cells. The capsules were prepared at the optimal combination by the traditional extrusion method composed of 8.66% w/v BGPI and 1.85% w/v alginate. The encapsulation efficiency was 97.24%, whereas the survival rates in an acidic condition and after the freeze-drying process were 95.56% and 95.20%, respectively-higher than those using either BGPI or alginate as the encapsulating agent individually. The designed capsules increased the probiotic L. rhamnosus GG survival relative to free cells in a simulated gastric fluid by 5.00 log cfu/ml after 3 h and in a simulated intestinal fluid by 8.06 log cfu/ml after 4 h. The shelf-life studies of the capsules over 6 months at 4 °C and 30 °C indicated that the remaining number of viable cells in a BGPI-alginate capsule was significantly higher than that of free cells in both temperatures. It was demonstrated that the BGPI-alginate capsule could be utilized as a new probiotic carrier for enhanced gastrointestinal transit and storage applied in food and/or pharmaceutical products.

Pre-cultivation with Selected Prebiotics Enhances the Survival and the Stress Response of Lactobacillus rhamnosus Strains in Simulated Gastrointestinal Transit

In our study, we dwelled upon combinations of lactobacilli/prebiotics, considering four different strains belonging to the Lactobacillus rhamnosus species, including Lactobacillus rhamnosus GG (LGG), and different prebiotics often found in commercial synbiotic products, such as inulin, lactulose and polyols mannitol and sorbitol. In the first step of the research, the survival, the growth kinetic parameters and the protein expression of Lb. rhamnosus strains cultivated in presence of the different prebiotics as a unique carbon source were evaluated. In the second step, the influence of pre-cultivation in medium added of metabolizable prebiotics on the strains survival to simulated gastrointestinal (GI) transit, assayed without prebiotics addition, was estimated. Our results showed that the presence in the medium of certain low fermented prebiotics, specific for each strain, represents a stress factor that significantly affects the growth of Lb. rhamnosus strains, inducing the up-regulation of several proteins. In detail, all added prebiotics used as unique carbon source caused a growth retard compared with glucose, as testified by increased values of the lag phase and decreased values of the μmax. Mannitol evidenced intermediate μmax values between those registered with glucose and those detected with the other assayed prebiotics. Moreover, the cultivation with prebiotics induced the over expression of 7 protein bands. Interestingly, we found a correlation between the up-regulation of two specific stress proteins, called P4 (ATP-binding subunit Clpx) and P7 (GrpE), and the death kinetic parameters (resistance and cells viability) registered during the simulated GI transit of strains pre-cultivated with specific, low fermented prebiotics. Specifically, the highest resistance and gastric-vitality scores were highlighted for the strain AT195 when pre-cultivated in presence of sorbitol. Conversely, the lowest values were found in the case of DSM20021 pre-cultivated with mannitol. Among the up-regulated stress proteins, P7 resulted involved in the response to the starvation. Finally, it is possible to conclude that the pre-cultivation with certain prebiotics as a unique carbon source represents a strain-specific, sub-lethal stress able to enhance the resistance of Lb. rhamnosus strains and consequently their viability under simulated GI transit.

Recent Advances in Screening of Anti-Campylobacter Activity in Probiotics for Use in Poultry

Campylobacteriosis is the most common cause of bacterial gastroenteritis worldwide. Campylobacter species involved in this infection usually include the thermotolerant species Campylobacter jejuni. The major reservoir for C. jejuni leading to human infections is commercial broiler chickens. Poultry flocks are frequently colonized by C. jejuni without any apparent symptoms. Risk assessment analyses have identified the handling and consumption of poultry meat as one of the most important sources of human campylobacteriosis, so elimination of Campylobacter in the poultry reservoir is a crucial step in the control of this foodborne infection. To date, the use of probiotics has demonstrated promising results to reduce Campylobacter colonization. This review provides recent insights into methods used for probiotic screening to reduce the prevalence and colonization of Campylobacter at the farm level. Different eukaryotic epithelial cell lines are employed to screen probiotics with an anti-Campylobacter activity and yield useful information about the inhibition mechanism involved. These in vitro virulence models involve only human intestinal or cervical cell lines whereas the use of avian cell lines could be a preliminary step to investigate mechanisms of C. jejuni colonization in poultry in the presence of probiotics. In addition, in vivo trials to evaluate the effect of probiotics on Campylobacter colonization are conducted, taking into account the complexity introduced by the host, the feed, and the microbiota. However, the heterogeneity of the protocols used and the short time duration of the experiments lead to results that are difficult to compare and draw conclusions at the slaughter-age of broilers. Nevertheless, the combined approach using complementary in vitro and in vivo tools (cell cultures and animal experiments) leads to a better characterization of probiotic strains and could be employed to assess reduced Campylobacter spp. colonization in chickens if some parameters are optimized.