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

An all-in-one strategy for the simultaneous production of bioplastics and degrading enzymes in engineered Escherichia coli

Bioplastics are promising alternatives for traditional plastics, which contribute significantly to environmental pollution and have a detrimental impact on ecosystems. To advance their use, further research into bioplastic biodegradation is essential. In this study, we propose a novel approach for simultaneous polyhydroxybutyrate (PHB) and degrading enzyme production in a single-cell system using engineered Escherichia coli. Typically, PHB depolymerases, such as PhaZ, disrupt bioplastic synthesis in cells, leading to a self-defeating cycle of production and degradation. To counter this, we introduced synthetic PHB production genes and triacylglycerol lipase (TGL) from Bacillus sp. JY35, along with a native signal peptide for secretion. This enabled PHB accumulation inside the cells while TGL was secreted into the supernatant. The concentrations of PHB produced with and without TGL were similar (31.44 % PHB with TGL and 32.12 % PHB without TGL). TGL was efficiently secreted in E. coli, achieving specific esterase activities of 7.1 U/mg and 15.7 U/mg for p-Nitrophenyl butyrate and p-nitrophenyl octanoate, respectively, and degraded PHB film by 30.1 % over 14 d. Moreover, TGL retained 86 % and 91 % of its activities for the C4 and C8 substrates, respectively, after 30 d of storage at room temperature, suggesting potential use PHB degradation after use. Our study demonstrates a straightforward one-month circular cycle for bioplastic production and degradation by a single producer.

Gut microbiome and liver diseases

Symbiotic microbiota plays a crucial role in the education, development, and maintenance of the host immune system, significantly contributing to overall health. Through the gut-liver axis, the gut microbiota and liver have a bidirectional relationship that is becoming increasingly evident as more research highlights the translocation of the gut microbiota and its metabolites. The focus of this narrative review is to examine and discuss the importance of the gut-liver axis and the enterohepatic barrier in maintaining overall health. Additionally, we emphasize the crucial role of the gut microbiome in liver diseases and explore potential therapeutic strategies for liver diseases by manipulating the microbiota.

Overview of Glycometabolism of Lactic Acid Bacteria During Freeze-Drying: Changes, Influencing Factors, and Application Strategies

Lactic acid bacteria (LAB) play a vital role in food fermentation and probiotics microeconomics. Freeze-drying (FD) is a commonly used method for preserving LAB powder to extend its shelf life. However, FD induces thermal, osmotic, and mechanical stresses that can impact the glycometabolism of LAB, which is the process of converting carbohydrates into energy. This review explores the effect of FD on glycometabolism, factors influencing glycometabolism, and feasible strategies in the FD process of LAB. During the three stages of FD, freezing, primary drying or sublimation, and second drying, the glycolytic activity of LAB is disrupted in the freezing stage; further, the function of glycolytic enzymes such as hexokinase, phosphofructokinase, and pyruvate kinase is hindered, and adenosine triphosphate (ATP) production drops significantly in the sublimation stage; these enzyme activities and ATP production nearly cease and exopolysaccharide (EPS) synthesis alters during the secondary drying stage. Factors such as strain variations, pretreatment techniques, growth medium components, FD parameters, and water activity influence these changes. To counteract the effects of FD on LAB glycometabolism, strategies like cryoprotectants, encapsulation, and genetic engineering can help preserve their glycometabolic activity. These methods protect LAB from harsh FD conditions, safeguarding glycolytic flux and enzymatic processes involved in carbohydrate metabolism. A deeper understanding of these glycometabolic changes is essential for optimizing FD processes and enhancing the use of LAB in food, medicine, and biotechnology, ultimately improving their performance upon rehydration.

Shelf-Stable Sporosarcina pasteurii Formulation for Scalable Laboratory and Field-Based Production of Biocement

Biocement is an environmentally friendly alternative to traditional cement that is produced via microbially induced calcium carbonate precipitation (MICP) and has great potential to mitigate the environmental harms of cement and concrete use. Current production requires on-site bacterial cultivation and the application of live culture to target materials, lacking the convenience of stable formulas that enable broad adoption and application by nonscientific professionals. Here, we report the development of a dry shelf-stable formulation of Sporosarcina pasteurii, the model organism for biocement production. At laboratory scale, when inoculated at an equivalent concentration of viable cells, we show that this formulation produces biocement equal in strength to that produced using live cell cultures. We further demonstrate that this formulation forms biocement in the field within 24 h, leading to ground improvement with increased bearing capacity. These results illustrate that preserved, shelf-stable bacteria can contribute to rapid biocement production and can be adopted for scaled geotechnical and construction purposes.

Improving the physical stability of Lactobacillus plantarum LP90 during storage by mixing carboxymethylated dextran-whey protein conjugates and small-molecule sugars

To explore the effect of small-molecule sugars on the physical stability of microcapsules and enhance probiotic preservation, carboxymethylated dextran and whey protein conjugate (WP-CD5d) by Maillard reaction were used as the wall material. Trehalose, lactose, and sucrose were used as lyoprotectants to encapsulate Lactobacillus plantarum LP90 (LP90) during storage, forming microcapsules labeled as WP-CD5dH, WP-CD5dR, and WP-CD5dZ, respectively. WP-CD5dH and WP-CD5dR exhibited the highest viability after freeze-drying, with survival rates of 97.8 % ± 0.9 % and 98.5 % ± 0.5 % respectively. LP90 microcapsules exhibited strong resistance to simulated gastrointestinal fluid over 5 h. The Guggenheim-Anderson-de Boer (GAB) and Gordon-Taylor model showed that WP-CD5dH had the best reduction in water plasticization (k was 4.0). 1H NMR spectra confirmed that WP-CD5dH exhibited the lowest molecular mobility. Furthermore, the storage experiment showed that WP-CD5dH provided the best protection for LP90 at 11 % RH, with a K value of 0.021. These results suggest that the probiotic mechanism of small-molecule sugars involves forming intermolecular forces with WP-CD5d, which helps to maintain the glassy state.

Lactiplantibacillus plantarum encapsulated by chitosan-alginate and soy protein isolate-reducing sugars conjugate for enhanced viability

To investigate the protective effects of various wall materials on probiotics, two types of Lactiplantibacillus plantarum 90 (Lp90) microcapsules were prepared using sodium alginate and chitosan (Lp-AC), soy protein isolate (SPI) and reducing sugars conjugate (Lp -MRP) as wall materials, respectively. The physical properties, cell viability under different conditions and the application of the microcapsules were investigated. Results showed that the selected wall materials were safe to Lp90 and their simulated digestion products exhibited antioxidant activities and prebiotic properties. The encapsulation efficiencies of Lp-AC and Lp-MRP were above 80 %. Both microcapsules significantly enhanced cell survival rates under various conditions including low pH, bile salts, thermal processing, mechanical force, storage, and gastrointestinal digestion, with Lp-MRP demonstrating superior protective effects. When incorporated into milk and orange juice and stored at 4 °C for 28 d, the colony counts of beverages containing Lp90 microcapsules exceeded 6 Log CFU/mL, with minimal changes in total soluble solids. Lp-MRP exhibited higher cell viability and smaller viscosity changes at 25 °C for 28 d. Therefore, the single-layer encapsulation using SPI and reducing sugars conjugate showed promise over traditional chitosan-alginate double-layer encapsulation concerning probiotic protection, targeted delivery, and application.

Mechanistic insights into the changes of biological activity and physicochemical characteristics in Lacticaseibacillus paracasei fortified milk powder during storage

To clarify the change mechanism of biological activity and physicochemical characteristics in Lacticaseibacillus paracasei JY025 fortified milk powder (LFMP) during storage, morphological observation, JY025 survival, storage stability, and metabolomics of LFMP were determined during the storage period in this study. The results showed that the LFMP had a higher survival rate of JY025 compared with the bacterial powder of JY025 (LBP) during storage, which suggested that milk powder matrix could reduce strain JY025 mortality under prolonged storage in the LFMP samples. The fortification of strain JY025 also affected the stability of milk powder during the storage period. There was lower water activity and higher glass transition temperature in LFMP samples compared with blank control milk powder (BCMP) during storage. Moreover, the metabolomics results of LFMP indicated that vitamin degradation, Maillard reaction, lipid oxidation, tricarboxylic acid cycle, and lactobacilli metabolism are interrelated and influence each other to create complicated metabolism networks.

Probiotic Bacteria Survival and Shelf Life of High Fibre Plant Snack - Model Study

The study aimed to develop plant-based model snacks that are high in fibre, contain probiotic bacteria and are convenient for long-term storage. The research focused on selecting a suitable form of probiotic bacteria (active biomass, microencapsulated, freeze-dried), inoculation method (in the base mass or in the filling of a snack) and appropriate storage conditions (4°Cor 20 °C). The potential synbiotic properties were evaluated. The microencapsulated bacteria had the highest survival rate at 4 °C, while the freeze-dried bacteria showed better survival rates at 20 °C. Probiotics had a higher survival rate when enclosed inside snacks with a low water activity (aw = 0.27) peanut butter filling than in snacks without filling (aw = 0.53). Enclosing the probiotics in a low aw filling ensures their survival at ambient temperature for 5 months at a count higher than 6 log CFU/g. The snacks exhibited high antioxidant capacity (average 300 mg ascorbic acid equivalent/100 g), polyphenol content (average 357 mg gallic acid equivalent/100 g) and high fibre content (average 10.2 g/100 g). The sensory analysis showed a high overall quality of the snacks (average 7.1/10 of the conventional units). Furthermore, after six months of storage, significant changes were observed in the antioxidant properties, polyphenol content and texture of the snacks, while their sensory quality remained unchanged. Moreover, a potential synbiotic effect was observed. The method used to assess bacterial growth indicated significantly higher values in the model snacks compared to a control sample. Therefore, this study has effectively addressed the gap in knowledge regarding the survival of probiotics in snacks of this nature.

New clues for postbiotics to improve host health: a review from the perspective of function and mechanisms

Strain activity and stability severely limit the beneficial effects of probiotics in modulating host health. Postbiotics have emerged as a promising alternative as they can provide similar or even enhanced efficacy to probiotics, even under inactivated conditions. This review introduces the ingredients, preparation, and identification techniques of postbiotics, focusing on the comparison of the advantages and limitations between probiotics and postbiotics based on their mechanisms and applications. Inactivation treatment is the most significant difference between postbiotics and probiotics. We highlight the use of emerging technologies to inactivate probiotics, optimize process conditions to maintain the activity of postbiotics, or scale up their production. Postbiotics have high stability which can overcome unfavorable factors, such as easy inactivation and difficult colonization of probiotics after entering the intestine, and are rapidly activated, allowing continuous and rapid optimization of the intestinal microecological environment. They provide unique mechanisms, and multiple targets act on the gut-organ axis, co-providing new clues for the study of the biological functions of postbiotics. We summarize the mechanisms of action of inactivated lactic acid bacteria, highlighting that the NF-κB and MAPK pathways can be used as immune targeting pathways for postbiotic modulation of host health. Generally, we believe that as the classification, composition, and efficacy mechanism of postbiotics become clearer they will be more widely used in food, medicine, and other fields, greatly enriching the dimensions of food innovation. © 2024 Society of Chemical Industry.

Study of Lactobacillus plantarum coated with Tremella polysaccharides to improve its intestinal adhesion

BACKGROUND

The adhesion of probiotics to the intestine is crucial for their probiotic function. In previous studies, Tremella polysaccharides (TPS) (with sodium casein) have shown the potential to encapsulate probiotics and protect them in a simulated gastrointestinal tract. This study explored the effect of TPS (with sodium casein) on the adhesion of probiotics.

RESULTS

Lactobacillus plantarum was coated with TPS and sodium casein in different proportions, and was freeze-dried. The rheological properties of the mixture of probiotics powder and mucin solution were determined by static and dynamic rheological analysis. Aqueous solutions of probiotic powder and mucin mixture exhibited pseudoplastic fluid rheological properties. The higher the proportion of TPS content, the higher the apparent viscosity and yield stress. The mixed bacterial powder and mucin fluid displayed thixotropy and was in accordance with the Herschel-Bulkley model. The TPS increased the bio-adhesive force of the probiotic powder and mucin. When using TPS as the only carbon source, the adhesion of L. plantarum to Caco-2 cells increased by 228% in comparison with glucose in vitro. Twelve adhesive proteins were also detected in the whole-cell proteome of L. plantarum. Among them, ten adhesive proteins occurred abundantly when grown with TPS as a carbon source.

CONCLUSION

Tremella polysaccharides therefore possess probiotic properties and can promote the intestinal adhesion of L. plantarum. © 2024 Society of Chemical Industry.

Nutrient consumption patterns of Lactobacillus acidophilus

BACKGROUND

One of the greatest challenges in using Lactobacillus acidophilus as a probiotic is acid stress. The current research aimed to identify substances that help L. acidophilus resist acid stress; this was achieved through assessing its nutrient consumption patterns under various pH conditions.

RESULTS

The consumption rates of alanine, uracil, adenine, guanine, niacin, and manganese were consistently higher than 60% for L. acidophilus LA-5 cultured at pH 5.8, 4.9, and 4.4. The consumption rates of glutamic acid + glutamine and thiamine increased with decreasing pH and were higher than 60% at pH 4.9 and 4.4. The viable counts of L. acidophilus LA-5 were significantly increased under the corresponding acidic stress conditions (pH 4.9 and 4.4) through the appropriate addition of either alanine (3.37 and 2.81 mmol L-1), glutamic acid + glutamine (4.77 mmol L-1), guanine (0.13 and 0.17 mmol L-1), niacin (0.02 mmol L-1), thiamine (0.009 mmol L-1), or manganese (0.73 and 0.64 mmol L-1) (P < 0.05). The viable counts of L. acidophilus LA-5 cultured in a medium supplemented with combined nutritional factors was 1.02-1.03-fold of the counts observed in control medium under all acid conditions (P < 0.05).

CONCLUSION

Alanine, glutamic acid + glutamine, guanine, niacin, thiamine, and manganese can improve the growth of L. acidophilus LA-5 in an acidic environment in the present study. The results will contribute to optimizing strategies to enhance the acid resistance of L. acidophilus and expand its application in the fermentation industry. © 2024 Society of Chemical Industry.

Stability and programmed sequential release of Lactobacillus plantarum and curcumin encapsulated in bilayer-stabilized W1/O/W2 double emulsion: Effect of pectin as protective shell

In order to overcome the problem that traditional W1/O/W2 double emulsions do not have targeted release performance, thereby better meeting the health needs of consumers, ovalbumin fibrils/pectin-based bilayer-stabilized double emulsion (OP-BDE) co-encapsulated with Lactobacillus plantarum and curcumin was constructed with pectin as the outer protective shell, which was expected to be used in the development of novel functional foods. The effects of pectin coating on the viability of Lactobacillus plantarum under conditions including storage, pasteurization, freeze-thaw cycles and in vitro simulated digestion were investigated. Results showed that pectin as protective shell could significantly enhance the tolerance of Lactobacillus plantarum to various environmental factors. Besides, the adsorption of pectin endowed OP-BDE with higher lipolysis and stronger protective effect on curcumin, remarkably improving the photostability and bioaccessibility of curcumin. In addition, in vitro simulated gastrointestinal release study indicated that OP-BDE possessed programmed sequential release property, allowing curcumin and Lactobacillus plantarum to be released in small intestine and colon, respectively. OP-BDE is the first reported co-delivery emulsion system with programmed release characteristic. This study provides new insights into OP-BDE in constructing co-delivery systems and programmed sequential release of active substances, and has potential reference and application value in actual food production.

Drying of probiotics to enhance the viability during preparation, storage, food application, and digestion: A review

Functional food products containing viable probiotics have become increasingly popular and demand for probiotic ingredients that maintain viability and stability during processing, storage, and gastrointestinal digestions. This has resulted in heightened research and development of powdered probiotic ingredients. The aim of this review is to overview the development of dried probiotics from upstream identification to downstream applications in food. Free probiotic bacteria are susceptible to various environmental stresses during food processing, storage, and after ingestion, necessitating additional materials and processes to preserve their activity for delivery to the colon. Various classic and emerging thermal and nonthermal drying technologies are discussed for their efficiency in preparing dehydrated probiotics, and strategies for enhancing probiotic survival after dehydration are highlighted. Both the formulation and drying technology can influence the microbiological and physical properties of powdered probiotics that are to be characterized comprehensively with various techniques. Furthermore, quality control during probiotic manufacturing and strategies of incorporating powdered probiotics into liquid and solid food products are discussed. As emerging technologies, structure-design principles to encapsulate probiotics in engineered structures and protective materials with improved survivability are highlighted. Overall, this review provides insights into formulations and drying technologies required to supplement viable and stable probiotics into functional foods, ensuring the retention of their health benefits upon consumption.

Carboxymethyl konjac glucomannan-chitosan complex nanogels stabilized emulsions incorporated into alginate as microcapsule matrix for intestinal-targeted delivery of probiotics: In vivo and in vitro studies

In this study, we developed a novel delivery system using carboxymethyl konjac glucomannan-chitosan (CMKGM-CS) nanogels stabilized single and double emulsion incorporated into alginate hydrogel as microcapsule matrix for intestinal-targeted delivery of probiotics. Through in vitro experiments, it was demonstrated that alginate hydrogel provided favorable biocompatible growth conditions for the proliferation of Lactobacillus reuteri (LR). The alginate hydrogel containing single (ASE) or double emulsions (ACG) enhanced the resistance of LR to various adverse environments. Simulated gastrointestinal digestion experiments revealed that the survivability of LR in free, CON, ASE and ACG group decreased by 6.45 log CFU/g, 4.21 log CFU/g, 1.26 log CFU/g and 0.65 log CFU/g, respectively. In vivo studies conducted in mice showed that ACG maintained its integrity during passage through the stomach and released the probiotics in the targeted intestinal area, whereas the pure alginate hydrogels (CON) were prematurely released in the gastrointestinal tract. Moreover, the viable counts of ACG in different intestinal segments (jejunum, ileum, cecum, and colon) were increased by 1.11, 1.42, 1.68, and 1.89 log CFU/g, respectively, after 72 h of oral administration compared to the CON group. This research contributed valuable insights into the development of an effective microbial delivery system with potential applications in the biopharmaceutical and food industries.

Safety Assessment and Probiotic Potential Comparison of Bifidobacterium longum subsp. infantis BLI-02, Lactobacillus plantarum LPL28, Lactobacillus acidophilus TYCA06, and Lactobacillus paracasei ET-66

Bifidobacterium longum subsp. infantis BLI-02, Lactobacillus paracasei ET-66, Lactobacillus plantarum LPL28, and Lactobacillus acidophilus TYCA06, isolated from healthy breast milk, miso, and the healthy human gut, were assessed for safety in this study. BLI-02, LPL28, TYCA06, and ET-66 exhibited no antibiotic resistance and mutagenic activity in the Ames test at the highest dosage (5000 μg/plate). No genotoxicity was observed in micronucleus and chromosomal aberration assays in rodent spermatogonia at the maximum dosage of 10 g/kg body weight (BW). No acute and sub-chronic toxicity occurred in mice and rats at the maximum tested dosage of 10 g/kg BW and 1.5 g/kg BW, respectively. The lyophilized powder of these strains survived a low pH and high bile salt environment, adhering strongly to Caco-2 cells. Unique antimicrobial activities were noted in these strains, with BLI-02 demonstrating the best growth inhibition against Vibrio parahaemolyticus, LPL28 exhibiting the best growth inhibition against Helicobacter pylori, and ET-66 showing the best growth inhibition against Aggregatibacter actinomycetemcomitans. Based on the present study, the lyophilized powder of these four strains appears to be a safe probiotic supplement at tested dosages. It should be applicable for clinical or healthcare applications.

Microencapsulation of Limosilactobacillus reuteri (DSM 23878) for application in infant formula: Heat resistance and bacterial viability during long-time storage

This study aimed to evaluate the survival capacity of the probiotic culture Limosilactobacillus reuteri (DSM 23878) to microencapsulation by spray drying, and its potential as component of an infant formula. Preliminary tests were performed between skim milk (SM) and infant formula (IF) as wall material and two inlet temperatures, evaluating the encapsulation efficiency, moisture content, water activity and stability, to choose the drying parameters. After drying in optimized conditions, the powder of microencapsulated L. reuteri was characterized and the viability after dilution in an infant formula at 70 °C was determined. In addition, the survival rate throughout 360 days of storage was assessed. As results, encapsulation efficiency was superior to 90 % in both wall materials. However, the use of IF as for microencapsulation produced microparticles with lower water activity (Aw) and moisture, as compared with the SM. Final microparticles produced with IF as wall material presented values of Aw, moisture content, and particle diameter averaged 0.11 ± 0.02, 2.10 ± 0.35 % and 10.30 ± 0.12 μm, respectively. The viability of microencapsulated L.reuteri decreased 1 Log CFU/mL after dilution at 70 °C and the powder maintained a survivor of 73.5 % after 365 days of storage at 4 °C. Thus, the microencapsulation by spray drying under the conditions of this study proved to be an effective technique to protect the probiotic L. reuteri for application in infant formulas, obtaining an adequate number of viable cells after reconstitution at 70 °C and during long time the storage.

Microencapsulation of Bacillus subtilis and oat β-glucan and their application as a synbiotic in fish feed

To improve survival during storage and exposure to adverse conditions, Bacillus subtilis was microencapsulated with oat β-glucan by spray-drying technology. The characterisation of the microcapsules was designed to compare free and microencapsulated cells through exposure to simulated gastric fluids (SGF) throughout storage for 90 days at different temperatures. The characterisation included analysis of efficiency, morphology, moisture, water activity, hygroscopicity, particle size, and zeta potential. The microcapsules presented a particle size of 1.5 ± 0.34 μm and an encapsulation efficiency of 77.9 ± 3.06%. After SGF, the survival of microencapsulated cells was 8.4 ± 0.07 log CFU mL-1 while that of free cells was 7.6 ± 0.06 log CFU mL-1. After 90 days of storage, only microencapsulated cells remained above 6 log-unit of viability. In conclusion, spray-drying technique combined with the addition of oat β-glucan proved to be an efficient method to protect B. subtilis under storage and SGF with potential application in fish feed.

Probiotic-fortified fruit juices: Health benefits, challenges, and future perspective

Consumers' growing interest in using foods that improve health has motivated researchers and the food industry to develop new functional products, such as foods containing probiotics or live microbes. Probiotics have functional attributes that could satisfy most basic nutritional and therapeutic supplementation requirements. These microbes positively respond to clinical therapies against diseases and illnesses such as rotavirus-associated diarrhea, irritable bowel syndrome, and food allergies. Moreover, the role of probiotics in the prevention and treatment of obesity, diabetes, cancer, and diseases related to pathogenic microbes is an exciting and rapidly advancing research arena. Probiotic supplementation usually involves dairy products. However, because of the growing number of individuals affected by lactose intolerance and/or vegans, other food matrices like fruits, vegetables, cereals, and so on, have been studied as potential carriers for these microorganisms, presenting an alternative and better source in the process of assessing novel probiotic strains. The present review discusses the various factors affecting the survival of probiotics during storage in fruit juices, the possible effect of probiotics on sensory attributes and the overall acceptance of the products, and future technologies to improve the viability of probiotics.

Enhancing bioavailability of natural extracts for nutritional applications through dry powder inhalers (DPI) spray drying: technological advancements and future directions

Natural ingredients have many applications in modern medicine and pharmaceutical projects. However, they often have low solubility, poor chemical stability, and low bioavailability in vivo. Spray drying technology can overcome these challenges by enhancing the properties of natural ingredients. Moreover, drug delivery systems can be flexibly designed to optimize the performance of natural ingredients. Among the various drug delivery systems, dry powder inhalation (DPI) has attracted much attention in pharmaceutical research. Therefore, this review will focus on the spray drying of natural ingredients for DPI and discuss their synthesis and application.

VIABILITY OF MICROENCAPSULATED PROBIOTICS (LACTOBACILLUS REUTERI) IN GUAVA JUICE

Probiotics play a pivotal role to reduce gastrointestinal problems by exerting a drastic effect on various pathogenic microflora of the colon. Lactobacillus reuteri CECT-925 loaded beads were prepared by emulsion containing sodium alginate and sesame seed oil. Encapsulation was done by spraying emulsion into a 0.5% solution of calcium chloride. Microencapsulated probiotics incorporated guava juice was assessed for physicochemical analysis at the 15-day interval for 60 days. The juice was tested for probiotics viability, titratable acidity, pH, total soluble solids and organoleptic properties. In the control sample, viable counts of encapsulated probiotics were reduced from 7.68 to 1.96 log10 CFU/ml while in T1, T2 and T3 the initial numbers 7.39, 7.7 and 7.87 were reduced to 5.97, 6.87 and 6.02 log10 CFU/ml respectively at the termination of the storage period. However, pH and sensory scores decreased while total soluble solids and titratable acidity increased. Results indicated that microencapsulation by sodium alginate in combination with sesame oil retained the viability of Lactobacillus reuteri > 90% in guava juice. The acceptability of the product was 82.04% till the end of the storage period

Ultrasound-assisted multilayer Pickering emulsion fabricated by WPI-EGCG covalent conjugates for encapsulating probiotics in colon-targeted release

This study demonstrated the influences of ultrasound-assisted multilayer Pickering double emulsion capsules on the pasteurization and gastrointestinal digestive viability of probiotic (L. plantarum) strain liquid. Firstly, the role of ultrasonic homogenization on the morphology of W₁/O/W₂ double emulsions were studied. The double emulsion formed by ultrasonic intensity at 285 W had a single and narrow distribution with smallest droplet size. The double emulsion particles were then coated with chitosan(Chi), alginate (Alg), and CaCl₂(Ca). The multilayer emulsion after pasteurization and gastrointestinal digestion both had the highest viability at 5 coating layers, but its particle size (108.65 μm) exceeded the limit of human oral sensory (80 μm). It could be noted that the deposition of 3-4 layers of coating had similar activity after pasteurization/GIT digestion. And droplets with 3 layers of coating were the minimum and most available formulation for encapsulated probiotics (L. plantarum). Hence, the results suggest that the use of ultrasound-assisted multilayer emulsions encapsulated with probiotics in granular food and pharmaceutical applications is a promising strategy.

Novel Functional Grape Juices Fortified with Free or Immobilized Lacticaseibacillus rhamnosus OLXAL-1

During the last decade, a rising interest in novel functional products containing probiotic microorganisms has been witnessed. As food processing and storage usually lead to a reduction of cell viability, freeze-dried cultures and immobilization are usually recommended in order to maintain adequate loads and deliver health benefits. In this study, freeze-dried (free and immobilized on apple pieces) Lacticaseibacillus rhamnosus OLXAL-1 cells were used to fortify grape juice. Juice storage at ambient temperature resulted in significantly higher (>7 log cfu/g) levels of immobilized L. rhamnosus cells compared to free cells after 4 days. On the other hand, refrigerated storage resulted in cell loads > 7 log cfu/g for both free and immobilized cells for up to 10 days, achieving populations > 109 cfu per share, with no spoilage noticed. The possible resistance of the novel fortified juice products to microbial spoilage (after deliberate spiking with Saccharomyces cerevisiae or Aspergillus niger) was also investigated. Significant growth limitation of both food-spoilage microorganisms was observed (both at 20 and 4 °C) when immobilized cells were contained compared to the unfortified juice. Keynote volatile compounds derived from the juice and the immobilization carrier were detected in all products by HS-SPME GC/MS analysis. PCA revealed that both the nature of the freeze-dried cells (free or immobilized), as well as storage temperature affected significantly the content of minor volatiles detected and resulted in significant differences in the total volatile concentration. Juices with freeze-dried immobilized cells were distinguished by the tasters and perceived as highly novel. Notably, all fortified juice products were accepted during the preliminary sensory evaluation.

Gut microbiota modulation via short-term administration of potential probiotic kefir yeast Kluyveromyces marxianus A4 and A5 in BALB/c mice

Kefir yeast, Kluyveromyces marxianus, has been evaluated for its potential probiotic properties-survivability, non-pathogenicity, and antioxidant and anti-microbial activities. However, host gut microbiota modulation of kefir yeasts remains unclear. Here, we compared kefir yeast strains K. marxianus A4 (Km A4) and K. marxianus A5 (Km A5) with Saccharomyces boulardii ATCC MYA-796 (Sb MYA-796) by investigating their adherence to colorectal adenocarcinoma (Caco-2) cells and gut microbiota modulation in BALB/c mice. The kefir yeast strains exhibited higher intestinal cell adhesion than Sb MYA-796 (p < 0.05). Bacteroidetes, Bacteroidales, and Bacteroides were more abundant in the 1 × 108 CFU/mL of Km A4 treatment group than in the control group (p < 0.05). Moreover, 1 × 108 CFU/mL of Km A5 increased Corynebacteriales and Corynebacterium compared to the 1 × 108 CFU/mL of Km A4 treatment group (p < 0.01). The results showed that Km A4 and Km A5 had good Caco-2 cell adhesion ability and modulated gut microbiota upon short-term administration in healthy mice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01268-3.

Use of maltodextrin, sweet potato flour, pectin and gelatin as wall material for microencapsulating Lactiplantibacillus plantarum by spray drying: Thermal resistance, in vitro release behavior, storage stability and physicochemical properties

Different plant products and co-products have been studied as wall materials for the microencapsulation of probiotics due to the need for new lost-cost, abundant, and natural materials. In this study, microparticles were developed by spray drying using different combinations of conventional materials such as maltodextrin, pectin, gelatin, and agar-agar with unconventional materials such as sweet potato flour to microencapsulate Lactiplantibacillus plantarum. The microparticles obtained were evaluated for encapsulation efficiency, thermal resistance, and rupture test. The most resistant microparticles were characterized and evaluated for probiotic viability during storage and survival to in vitro gastrointestinal conditions. Microparticles A (10 % maltodextrin, 5 % sweet potato flour, and 1 % pectin) and B (10 % maltodextrin, 4 % sweet potato flour, and 2 % gelatin) showed high thermal resistance (>59 %) and survival in acidic conditions (>80 %). L. plantarum in microparticles A and B remained viable with counts > 6 log CFU.g^-1 for 45 days at 8 °C and -18 °C and resisted in vitro gastrointestinal conditions after processing with counts of 8.38 and 9.10 log CFU.g^-1, respectively. Therefore, the selected microparticles have great potential for application in different products in the food industry, as they promote the protection and distribution of probiotic microorganisms.

Stability and Survivability of Alginate Gum-Coated Lactobacillus rhamnosus GG in Simulated Gastrointestinal Conditions and Probiotic Juice Development

Survivability of probiotics is severely affected by harsh gastrointestinal conditions. In the present study, microbeads of Lactobacillus rhamnosus GG were formulated using alginate (1.5% w/v) and combination of alginate (1.5% w/v) with xanthan gum (0.5% w/v) through an emulsion technique to improve bacterial viability in low pH orange juice and in gastrointestinal conditions. The microbeads were tested for encapsulation efficiency, survivability in bile salt, SGF (simulated gastric juice), SIF (simulated intestinal fluid), and storage stability. Probiotic orange juice was formulated and tested for physicochemical parameters (pH, titratable acidity, and total sugars) and sensorial properties during storage. Gum-coated alginate microbeads (T3) showed higher encapsulation efficiency, i.e., 95.2% compared to alginate microbeads (T2), i.e., 86.85%. Similarly, T3 showed the highest resistance against bile salt (8.50 log CFU/g), SGF (7.95 log CFU/g), and SIF (8.0 log CFU/g) during 80 min exposure compared to T2 and free cells. The viability of gum-coated alginate beads (T3) remained above 107 CFU/g in gastrointestinal conditions and at the end of 21 days storage (8.3 log CFU/mL). All physicochemical parameters of probiotic juice were significantly ( $p\le 0.05$ ) decreased with respect to storage except acidity. In addition, minimal changes in physicochemical parameters were observed in T3 compared to other treatments. Treatment had no significant impact on the sensory characteristics of juice, but storage had a significant effect ( $p\le 0.05$ ) on the sensory characteristics of juice. The alginate gum microbeads improve the survivability of probiotics for targeted delivery. Hence, encapsulated probiotics can be used for functional beverage development to take advantage of their therapeutic benefits.

Review on Preventive Measures to Reduce Post-Weaning Diarrhoea in Piglets

In many countries, medical levels of zinc (typically as zinc oxide) are added to piglet diets in the first two weeks post-weaning to prevent the development of post-weaning diarrhoea (PWD). However, high levels of zinc constitute an environmental polluting agent, and may contribute to the development and/or maintenance of antimicrobial resistance (AMR) among bacteria. Consequently, the EU banned administering medical levels of zinc in pig diets as of June 2022. However, this may result in an increased use of antibiotic therapeutics to combat PWD and thereby an increased risk of further AMR development. The search for alternative measures against PWD with a minimum use of antibiotics and in the absence of medical levels of zinc has therefore been intensified over recent years, and feed-related measures, including feed ingredients, feed additives, and feeding strategies, are being intensively investigated. Furthermore, management strategies have been developed and are undoubtedly relevant; however, these will not be addressed in this review. Here, feed measures (and vaccines) are addressed, these being probiotics, prebiotics, synbiotics, postbiotics, proteobiotics, plants and plant extracts (in particular essential oils and tannins), macroalgae (particularly macroalgae-derived polysaccharides), dietary fibre, antimicrobial peptides, specific amino acids, dietary fatty acids, milk replacers, milk components, creep feed, vaccines, bacteriophages, and single-domain antibodies (nanobodies). The list covers measures with a rather long history and others that require significant development before their eventual use can be extended. To assess the potential of feed-related measures in combating PWD, the literature reviewed here has focused on studies reporting parameters of PWD (i.e., faeces score and/or faeces dry matter content during the first two weeks post-weaning). Although the impact on PWD (or related parameters) of the investigated measures may often be inconsistent, many studies do report positive effects. However, several studies have shown that control pigs do not suffer from diarrhoea, making it difficult to evaluate the biological and practical relevance of these improvements. From the reviewed literature, it is not possible to rank the efficacy of the various measures, and the efficacy most probably depends on a range of factors related to animal genetics and health status, additive doses used, composition of the feed, etc. We conclude that a combination of various measures is probably most recommendable in most situations. However, in this respect, it should be considered that combining strategies may lead to additive (e.g., synbiotics), synergistic (e.g., plant materials), or antagonistic (e.g., algae compounds) effects, requiring detailed knowledge on the modes of action in order to design effective strategies.

Characteristics of Probiotic Preparations and Their Applications

The probiotics market is one of the fastest growing segments of the food industry as there is growing scientific evidence of the positive health effects of probiotics on consumers. Currently, there are various forms of probiotic products and they can be categorized according to dosage form and the site of action. To increase the effectiveness of probiotic preparations, they need to be specifically designed so they can target different sites, such as the oral, upper respiratory or gastrointestinal tracts. Here we review the characteristics of different dosage forms of probiotics and discuss methods to improve their bioavailability in detail, in the hope that this article will provide a reference for the development of probiotic products.

Effects of Lactobacillus supplementation on glycemic and lipid indices in overweight or obese adults: A systematic review and meta-analysis

BACKGROUND & AIMS

Recent evidence suggests that gut microbiota may represent an important factor to affect the development of obesity and obesity-related diseases. Although several randomized controlled trials (RCTs) have explored the ability of Lactobacillus to improve metabolic parameters in adults who are overweight or obese, their findings have been inconsistent and require further analysis. Therefore, this systematic review and meta-analysis aimed to determine the ability of Lactobacillus supplementation to improve glycemic control, the lipid profile, and blood pressure in adults who are overweight or obese.

METHODS

Seven electronic databases and two trial registers were searched up to April 2022 to identify eligible RCTs evaluating the effects of Lactobacillus supplementation in overweight or obese adults. Mean differences (MDs) or standardized mean differences were pooled using a random-effects model.

RESULTS

Nine eligible RCTs with 598 participants were included. We found that Lactobacillus supplementation significantly reduced low-density lipoprotein cholesterol (MD -5.27 mg/dL; 95% confidence interval [CI] -8.28, -2.25; P = 0.0006) and total cholesterol (MD -4.84 mg/dL; 95% CI -8.29, -1.39; P = 0.006), particularly when taken in capsule, powder, or tablet form, for 12 weeks, as ≥1 × 10¹⁰ colony forming units/day, or as part of a normal diet. Benefits of Lactobacillus on fasting plasma glucose were seen after 12 weeks of supplementation (MD -1.81 mg/dL; 95% CI -3.08, -0.54; P = 0.005) and on triglycerides when taking a normal diet (MD -14.14 mg/dL; 95% CI -24.38, -3.91; P = 0.007). Lactobacillus had only a short-term beneficial effect on fasting plasma insulin and blood pressure and no significant beneficial effect on high-density lipoprotein cholesterol.

CONCLUSIONS

Lactobacillus supplementation has a beneficial effect on low-density lipoprotein cholesterol and total cholesterol in adults who are overweight or obese, and also on fasting plasma glucose and triglycerides under certain conditions. Therefore, Lactobacillus supplementation represents a promising approach in the management of obesity-related diseases.

Effective encapsulation of reuterin-producing Limosilactobacillus reuteri in alginate beads prepared with different mucilages/gums

The mainly aim of this study was to use mucilaginous solutions obtained from tamarind, mutamba, cassia tora, psyllium and konjac powdered to encapsulate reuterin-producing Limosilactobacillus reuteri in alginate beads by extrusion technique. In the particles were determined the bacterial encapsulation efficiency, cell viability during storage and survival under simulated gastric and intestinal conditions. Moreover, the reuterin production, its entrapment into the beads and the influence on viability of encapsulated microorganism were evaluated. Scanning electron microscopy and Fourier Transform Infrared spectroscopy were employed to characterize the produced particles. The beads showed a relatively spherical shape with homogenous distribution of L. reuteri. The use of gums and mucilages combined with alginate improved the encapsulation efficiency (from 93.2 to 97.4%), the viability of encapsulated bacteria during refrigerated storage (especially in prolonged storage of 20, 30 and 60 days) and the survival after exposure to gastric and enteric environments (from 67.7 to 76.6%). The L. reuteri was able to produce reuterin via bioconversion of glycerol in the film-forming solutions, and the entrapment of the metabolite was improved using konjac, mutamba and tamarind mucilaginous solutions in the encapsulation process (45, 44.57 and 41.25%, respectively). Thus, our findings confirm the great potential of these hydrocolloids to different further purposes, enabling its application as support material for delivery of chemical or biological compounds.

Colonization of the live biotherapeutic product VE303 and modulation of the microbiota and metabolites in healthy volunteers

Manipulation of the gut microbiota via fecal microbiota transplantation (FMT) has shown clinical promise in diseases such as recurrent Clostridioides difficile infection (rCDI). However, the variable nature of this approach makes it challenging to describe the relationship between fecal strain colonization, corresponding microbiota changes, and clinical efficacy. Live biotherapeutic products (LBPs) consisting of defined consortia of clonal bacterial isolates have been proposed as an alternative therapeutic class because of their promising preclinical results and safety profile. We describe VE303, an LBP comprising 8 commensal Clostridia strains under development for rCDI, and its early clinical development in healthy volunteers (HVs). In a phase 1a/b study in HVs, VE303 is determined to be safe and well-tolerated at all doses tested. VE303 strains optimally colonize HVs if dosed over multiple days after vancomycin pretreatment. VE303 promotes the establishment of a microbiota community known to provide colonization resistance.

Emerging Technologies and Coating Materials for Improved Probiotication in Food Products: a Review

From the past few decades, consumers' demand for probiotic-based functional and healthy food products is rising exponentially. Encapsulation is an emerging field to protect probiotics from unfavorable conditions and to deliver probiotics at the target place while maintaining the controlled release in the colon. Probiotics have been encapsulated for decades using different encapsulation methods to maintain their viability during processing, storage, and digestion and to give health benefits. This review focuses on novel microencapsulation techniques of probiotic bacteria including vacuum drying, microwave drying, spray freeze drying, fluidized bed drying, impinging aerosol technology, hybridization system, ultrasonication with their recent advancement, and characteristics of the commonly used polymers have been briefly discussed. Other than novel techniques, characterization of microcapsules along with their mechanism of release and stability have shown great interest recently in developing novel functional food products with synergetic effects, especially in COVID-19 outbreak. A thorough discussion of novel processing technologies and applications in food products with the incorporation of recent research works is the novelty and highlight of this review paper.

Joint protection strategies for Saccharomyces boulardii: exogenous encapsulation and endogenous biofilm structure

Biofilms are heterogeneous structures composed of microorganisms and the surrounding extracellular polymeric substances (EPS) that protect the microbial cells from harsh environments. Saccharomyces boulardii is the first yeast classified as a probiotic strain with unique properties. However, tolerance of S. boulardii biofilms to harsh environments especially during production and in the gastrointestine remains unknown. In this study, S. boulardii cells were encapsulated in alginate microcapsules and subsequently cultured to form biofilms, and their survival and tolerance were evaluated. Microencapsulation provided S. boulardii a confined space that enhanced biofilm formation. The thick alginate shell and the mature biofilm improved the ability of S. boulardii to survive under harsh conditions. The exogenous encapsulation and the endogenous biofilm structure together enhanced the gastrointestinal tolerance and thermotolerance of S. boulardii. Besides, as the alginate shell became thinner with an increase in the subsequent culture duration, the EPS of S. boulardii biofilms exerted an important protective effect in resisting high temperatures. The encapsulated biofilm of S. boulardii after 24-h culture exhibited 60 × higher thermotolerance at 60 °C (10 min), while those after 6-h and 24-h culture showed 1000 × to 550,000 × higher thermotolerance at 120 °C (1 min) compared with the planktonic cells without encapsulation. The present study's findings suggest that a combination of encapsulation and biofilm mode efficiently enhanced gastrointestinal tolerance and thermotolerance of S. boulardii. KEY POINTS: • Encapsulated S. boulardii in biofilm mode showed enhanced tolerance. • Exogenous shell and endogenous biofilm provided dual protection to S. boulardii.

Uranium removal from complex mining waters by alginate beads doped with cells of Stenotrophomonas sp. Br8: Novel perspectives for metal bioremediation

Uranium-containing effluents generated by nuclear energy industry must be efficiently remediated before release to the environment. Currently, numerous microbial-based strategies are being developed for this purpose. In particular, the bacterial strain Stenotrophomonas sp. Br8, isolated from U mill tailings porewaters, has been already shown to efficiently precipitate U(VI) as stable U phosphates mediated by phosphatase activity. However, the upscaling of this strategy should overcome some constraints regarding cell exposure to harsh environmental conditions. In the present study, the immobilization of Br8 biomass in an inorganic matrix was optimized to provide protection to the cells as well as to make the process more convenient for real-scale utilization. The use of biocompatible, highly porous alginate beads for Br8 cells immobilization resulted the best alternative when investigating by a multidisciplinary approach (High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM), Environmental Scanning Electron Microscopy (ESEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance, etc.) several consolidated entrapment methods. This biomaterial was applied to complex real U mining porewaters (containing 47 mg/L U) in presence of an organic phosphate source (glycerol-2-phosphate) to produce reactive free orthophosphates through Br8 phosphatase activity. Uranium immobilization rates around 98 % were observed after one cycle of 72 h. In terms of U removal ability as a function of biomass, Br8-doped alginate beads were determined to remove up to 1199.5 mg U/g dry biomass over two treatment cycles. Additionally, optimized conditions for storing Br8-doped beads and for a correct application were assessed. Results for U accumulation kinetics and HAADF-STEM/ESEM analyses revealed that U removal by the immobilized cells is a biphasic process combining a first passive U sorption onto bead and/or cell surfaces and a second slow active biomineralization. This work provides new practical insights into the biological and physico-chemical parameters governing a high-efficient U bioremediation process based on the phosphatase activity of immobilized bacterial cells when applied to complex mining waters under laboratory conditions.

Probiotic Supplements Improve Blood Glucose and Insulin Resistance/Sensitivity among Healthy and GDM Pregnant Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Probiotic supplements may be seen as a promising way to improve glucose metabolism. This study aimed to evaluate the effects of probiotic supplements on blood glucose, insulin resistance/sensitivity, and prevention of gestational diabetes mellitus (GDM) among pregnant women.

Methods

Eleven electronic databases were searched from inception to May 2020. Two authors independently identified randomized controlled trials (RCTs), assessed the eligibility and quality of the included studies, and then extracted data. The primary outcomes were fasting plasma glucose (FPG), 1 h and 2 h plasma glucose after 75 g oral glucose tolerance test (OGTT), HbA1c, fasting plasma insulin, insulin resistance, and insulin sensitivity. Fixed and random effect models were used to pool the results.

Results

A total of 20 RCTs involving 2972 participants were included according to the inclusion and exclusion criteria. The pooled results of this research showed that probiotic supplements could reduce the level of FPG (mean difference (MD) = −0.11; 95% CI = −0.15 to −0.04; P=0.0007), serum insulin (MD = −1.68; 95% CI = −2.44 to −0.92; P < 0.00001), insulin resistance (MD = −0.36; 95% CI = −0.53 to −0.20; P < 0.00001), and insulin sensitivity (MD = −21.80; 95% CI = −31.92 to −11.67; P < 0.00001). Regarding the subgroup analysis of different pregnant women, the effects of probiotics on FPG, insulin, and insulin resistance were more obvious among GDM and healthy women than among overweight/obese women. Furthermore, the differences were not significant in HbA1c (MD = −0.05; 95% CI = −0.12 to 0.03; P=0.23), 1 h OGTT (MD = −0.07; 95% CI = −0.25 to 0.10; P=0.42), and 2 h OGTT (MD = −0.03; 95% CI = −0.17 to 0.12; P=0.72).

Conclusion

This review found that probiotic supplements had certain functions to reduce the level of FPG and improve insulin, insulin resistance, and insulin sensitivity, especially for GDM and healthy pregnant women.

Effect of an In Vitro Proximal Gastrointestinal Tract on Viability of Commercially Available Equine Probiotics

Probiotics, by definition, are live micro-organisms and should remain viable when they reach the intended site of action which is typically the cecum and/or colon. In humans, probiotics often need enteric protection to survive transit through the proximal gastrointestinal (GI) tract. Typically, equine probiotics do not advertise enteric protection and to the author's knowledge the viability of equine probiotics after exposure to the proximal GI tract has not been evaluated. The objective of this study was to evaluate the effect of an in vitro simulation of the equine proximal GI tract on probiotic viability. We hypothesized that the simulated proximal GI tract would adversely effect microbial viability and that the adverse effects would be partially ameliorated by increasing the gastric pH to 4. A total of 11 products were evaluated of which six had at least one micro-organism that was adversely effected by exposure to the proximal GI tract and four of which had at least one micro-organism that was adversely affected when the gastric pH was increased to 4.0. Results from this study indicate that some micro-organisms in equine probiotics do not appear to be adversely affected by exposure to the equine proximal GI tract.

Comparison of protection and release behavior of different capsule polymer combinations based on L. acidophilus survivability and function and caffeine release

Oral administration of active pharmaceutical ingredients, nutraceuticals, enzymes or probiotics requires an appropriate delivery system for optimal bioactivity and absorption. The harsh conditions during the gastrointestinal transit can degrade the administered products, hampering their efficacy. Enteric or delayed-release pharmaceutical formulations may help overcome these issues. In a Simulator of Human Intestinal Microbial Ecosystem model (SHIME) and using caffeine as a marker for release kinetics and L. acidophilus survivability as an indicator for protection, we compared the performance of ten capsule configurations, single or DUOCAP® combinations. The function of L. acidophilus and its impact on the gut microbiota was further tested in three selected capsule types, combinations of DRcaps® capsule in DRcaps® capsule (DR-in-DR) and DRcaps® capsule in Vcaps® capsule (DR-in-VC) and single Vcaps® Plus capsule under colonic conditions. We found that under stomach and small intestine conditions, DR-in-DR and DR-in-VC led to the best performance both under fed and fasted conditions based on the slow caffeine release and the highest L. acidophilus survivability. The Vcaps® Plus capsule however, led to the quickest caffeine and probiotic release. When DR-in-DR, DR-in-VC and single Vcaps® Plus capsules were tested through the whole gastrointestinal tract, including under colonic conditions, caffeine release was found to be slower in capsules containing DRcaps® capsules compared to the single Vcaps® capsules. In addition, colonic survival of L. acidophilus was significantly increased under fasted conditions in DR-in-DR or DR-in-VC formulation compared to Vcaps® Plus capsule. To assess the impact of these formulations on the microbial function, acetate, butyrate and propionate as well as ammonia were measured. L. acidophilus released from DR-in-DR or DR-in-VC induced a significant increase in butyrate and a decrease in ammonia, suggesting a proliferation of butyrate-producing bacteria and reduction in ammonia-producing bacteria. These data suggest that L. acidophilus included in DR-in-DR or DR-in-VC reaching the colon is viable and functional, potentially contributing to changes in colonic microbiota composition and diversity.

Probiotic therapy for periodontal and peri-implant health - silver bullet or sham?

Probiotics are thought to be beneficial microbes that influence health-related outcomes through host immunomodulation and modulation of the bacteriome. Its reported success in the treatment of gastrointestinal disorders has led to further research on its potential applicability within the dental field due to similarities such as a polymicrobial aetiology and disease associated microbial-shifts. Although the literature is replete with studies demonstrating its efficacy, the use of probiotics in dentistry continues to polarise opinion. Here, we explore the evidence for probiotics and its effect on periodontal and peri-implant health. MEDLINE, EMBASE, and CENTRAL were systemically searched from June 2010 to June 2020 based on a formulated search strategy. Of 1,956 potentially relevant articles, we selected 27 double-blinded randomised clinical trials in the areas of gingivitis, periodontitis, residual pockets during supportive periodontal therapy, and peri-implant diseases, and reviewed their efficacy in these clinical situations. We observed substantial variation in treatment results and protocols between studies. Overall, the evidence for probiotic therapy for periodontal and peri-implant health appears unconvincing. The scarcity of trials with adequate power and follow-up precludes any meaningful clinical recommendations. Thus, the routine use of probiotics for these purposes are currently unsubstantiated. Further multi-centre trials encompassing a standardised investigation on the most promising strains and administration methods, with longer observation times are required to confirm the benefits of probiotic therapy for these applications.

Targeted Delivery of Probiotics: Perspectives on Research and Commercialization

Considering the significance of the gut microbiota on human health, there has been ever-growing research and commercial interest in various aspects of probiotic functional foods and drugs. A probiotic food requires cautious consideration in terms of strain selection, appropriate process and storage conditions, cell viability and functionality, and effective delivery at the targeted site. To address these challenges, several technologies have been explored and some of them have been adopted for industrial applicability. Encapsulation of probiotics has been recognized as an effective way to stabilize them in their dried form. By conferring a physical barrier to protect them from adverse conditions, the encapsulation approach renders direct benefits on stability, delivery, and functionality. Various techniques have been explored to encapsulate probiotics, but it is noteworthy that the encapsulation method itself influences surface morphology, viability, and survivability of probiotics. This review focuses on the need to encapsulate probiotics, trends in various encapsulation techniques, current research and challenges in targeted delivery, the market status of encapsulated probiotics, and future directions. Specific focus has been given on various in vitro methods that have been explored to better understand their delivery and performance.

Electrosprayed mucoadhesive alginate-chitosan microcapsules for gastrointestinal delivery of probiotics

Besides viability protection, a sufficiently prolonged gastrointestinal retention of probiotics has emerged as critically important in improving the functional effectiveness of gastrointestinal delivery of these microorganisms. In this work, we formulated pure, resistant starch-reinforced and chitosan-coated alginate microparticles using an electrospray technique and evaluated their performance as mucoadhesive probiotic formulations for gastrointestinal delivery. In addition, we designed and successfully validated a novel experimental set-up of in vitro wash-off mucoadhesion test, using a portable and low-cost USB microscope for fluorescence imaging. In our test, pure chitosan microparticles (positive control) exhibited the greatest mucoadhesive property, whereas the alginate-resistant starch ones (negative control) were the least retentive on a gastric mucosa. These electrosprayed formulations were spherically shaped, with a size range of 30-600 µm (60-1300 µm with chitosan coating). Moreover, model probiotic Lactobacillus plantarum loaded in alginate-starch formulations was better protected against simulated gastric conditions than in alginate ones, but not better than in the chitosan-coated ones.

Microencapsulation of probiotic lactobacilli with shellac as moisture barrier and to allow controlled release

BACKGROUND

Rapid dissolution in digestive tract and moisture sorption during ambient storage are the two challenges of dry probiotic preparations. To solve these problems, microcapsules with shellac (LAC) addition containing Limosilactobacillus reuteri TMW 1.656 were designed in this work to provide a good moisture barrier and to provide controlled release in digestive tract, based on the hydrophobicity and acid-resistance of LAC. Four microcapsules were prepared using the method of emulsification/external gelation based on the crosslinking reaction between alginate or LAC with calcium ion, including alginate/sucrose (ALG), alginate/shellac/sucrose (ALG/LAC), alginate/whey protein isolate/sucrose (ALG/WPI) and alginate/whey protein isolate/shellac/sucrose (ALG/WPI/LAC).

RESULTS

Measurements of physical properties showed that microcapsules with LAC addition (ALG/WPI/LAC and ALG/LAC) had larger particle size, much denser structure, lower hygroscopicity and slower solubilization in water, which agreed with the primary microcapsule design. Probiotic survivals in digestive juices followed the order of ALG/WPI/LAC ≥ ALG/WPI ≥ ALG/LAC > ALG. Probiotic stability after heating and ambient storage both exhibited the order of ALG/WPI/LAC > ALG/LAC ≈ ALG/WPI > ALG, which can be explained by the decreased hygroscopicity with adding LAC.

CONCLUSION

LAC addition contributed to better probiotic survivals after freeze drying, simulated digestion, heating and ambient storage, and whey protein isolate (WPI) addition had a synergistic effect. Microcapsule hygroscopicity was closely related with probiotic survivals after heating and ambient storage, while microcapsule solubilization was closely related with probiotic survivals in simulated juices. Within our knowledge, this is the first report to improve probiotic stability during ambient storage based on LAC hydrophobicity. © 2020 Society of Chemical Industry.