Microencapsulation of Lactobacillus reuteri DSM 17938 Cells Coated in Alginate Beads with Chitosan by Spray Drying to Use as a Probiotic Cell in a Chocolate Soufflé

The application of dietary fibre as microcapsule wall material in food processing

In the food industry, functional ingredients derived from active substances of natural sources and microbiological resources are gaining acceptance and demand due to their beneficial health properties. However, the inherent instability of these constituents poses a challenge in utilizing their functional properties. Microencapsulation with dietary fibre as wall material technology offers a promising solution, providing convenient manipulability and effective safeguarding of encapsulated substances. This paper presents a comprehensive overview of the current state of research on dietary fibre-based microcapsules in food processing. It examines their functional attributes, the preparation technology, and their applications within the food industry. Furthermore, the constraints associated with industrial production are discussed, as well as potential future developments. This article offers researchers a reference point and a theoretical basis for the selection of innovative food ingredients, the high-value utilisation of dietary fibre, and the design of conservation strategies for functional substances in food production.

Alginate Capsules: Versatile Applications and Production Techniques

Alginate is a natural polysaccharide commonly obtained from brown algae and is usually used in the food industry as an additive, specifically as a thickening, gelling, and emulsifying agent. Due to its polyanionic nature, it can crosslink in the presence of divalent or trivalent cations. This crosslinking process involves the formation of chemical bonds between the carboxylic groups of parallel chains, resulting in a solid structure. In this way, compounds of interest can be enclosed in a capsule or a bead. Thanks to this ability, possible applications of alginate capsules are countless: it is possible to range from the pharmaceutical to the nutritional fields, from the agri-food industry to the textile or cosmetic sectors. These capsules can protect the encapsulated ingredients, promote their delivery or controlled release, or be imagined as small-scale reactors. The present review describes the main techniques used to produce alginate capsules, and several examples of possible application fields are shown.

Microencapsulation for Pharmaceutical Applications: A Review

In order to improve bioavailability, stability, control release, and target delivery of active pharmaceutical ingredients (APIs), as well as to mask their bitter taste, to increase their efficacy, and to minimize their side effects, a variety of microencapsulation (including nanoencapsulation, particle size <100 nm) technologies have been widely used in the pharmaceutical industry. Commonly used microencapsulation technologies are emulsion, coacervation, extrusion, spray drying, freeze-drying, molecular inclusion, microbubbles and microsponge, fluidized bed coating, supercritical fluid encapsulation, electro spinning/spray, and polymerization. In this review, APIs are categorized by their molecular complexity: small APIs (compounds with low molecular weight, like Aspirin, Ibuprofen, and Cannabidiol), medium APIs (compounds with medium molecular weight like insulin, peptides, and nucleic acids), and living microorganisms (such as probiotics, bacteria, and bacteriophages). This article provides an overview of these microencapsulation technologies including their processes, matrix, and their recent applications in microencapsulation of APIs. Furthermore, the advantages and disadvantages of these common microencapsulation technologies in terms of improving the efficacy of APIs for pharmaceutical treatments are comprehensively analyzed. The objective is to summarize the most recent progresses on microencapsulation of APIs for enhancing their bioavailability, control release, target delivery, masking their bitter taste and stability, and thus increasing their efficacy and minimizing their side effects. At the end, future perspectives on microencapsulation for pharmaceutical applications are highlighted.

Chitosan-glucose derivative as effective wall material for probiotic yeasts microencapsulation

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.

Encapsulation of Bifidobacterium animalis subsp. lactis Through Emulsification Coupled with External Gelation for the Development of Synbiotic Systems

Aim of this work was the development of integrated and complex encapsulating systems that will provide more efficient protection to the probiotic strain Bifidobacterium animalis subsp. lactis (BB-12) in comparison to the conventional plain alginate beads. Within the scope of this study, the encapsulation of BB-12 through emulsification followed by external gelation was performed. For this purpose, a variety of alginate-based blends, composed of conventional and novel materials, were used. The results demonstrated that alginate beads incorporating 1% carrageenan or 2% nanocrystalline cellulose provided great protection to the viability of the probiotic bacteria during refrigerated storage (survival rates of 50.3% and 51.1%, respectively), as well as in vitro simulation of the gastrointestinal tract (survival rates of 38.7 and 42.0%, respectively). The incorporation of glycerol into the formulation of the beads improved the protective efficiency of the beads to the BB-12 cells during frozen storage, increasing significantly their viability compared to the plain alginate beads. Beads made of milk, alginate 1%, glucose 5%, and inulin 2% provided the best results in all cases. The microstructure of beads was assessed through SEM analysis and showed absence of free bacteria on the surface of the produced beads. Consequently, the encapsulation of BB-12 through emulsification in a complex encapsulating system was proved successful and effective.

Improvement of Probiotic Viability by Mixing with Ultrasound-Treated Yeast Cells and Spray Drying

The objective of the study was to determine the efficacy of ultrasound-treatment Saccharomyces cerevisiae and spray drying in preserving the viability of Lactiplantibacillus plantarum. The combination of ultrasound-treated S. cerevisiae and L. plantarum was evaluated. Next, the mixture was blended with maltodextrin and either Stevia rebaudiana-extracted fluid, prior to undergoing spray drying. The L. plantarum viability was assessed after the spray drying process, during storage, and in simulated digestive fluid (SDF) conditions. The results showed that the impact of ultrasound caused the crack and holes in the yeast cell wall. Besides, the moisture content values were not significantly different in all samples after spray drying. Although the amount of powder recovery in stevia-supplemented samples was not higher than that of the control sample, the L. plantarum viability was significantly improved after the spray drying process. The density of L. plantarum tended to be stable during the first 30 days of storage and decreased more rapidly after that. The results reveal that there was no statistically significant difference in the trend of the samples before and after storage. In the SDF test, the L. plantarum viability mixing with ultrasound-treated yeast cells in the spray drying samples was significantly improved. Besides, the presence of Stevia showed positive efficiency on the L. plantarum viability. The L. plantarum viability mixing with ultrasound-treated yeast cells and stevia-extracted fluid by spray drying process showed potential application due to making powder form which helped to improve the L. plantarum stability during the storage time.

Microencapsulation of Yarrowia lipolytica: cell viability and application in vitro ruminant diets

Microencapsulation is an alternative to increase the survival capacity of microorganisms, including Yarrowia lipolytica, a widely studied yeast that produces high-value metabolites, such as lipids, aromatic compounds, biomass, lipases, and organic acids. Thus, the present study sought to investigate the effectiveness of different wall materials and the influence of the addition of salts on the microencapsulation of Y. lipolytica, evaluating yield, relationship with cell stability, ability to survive during storage, and in vitro application of ruminant diets. The spray drying process was performed via atomization, testing 11 different compositions using maltodextrin (MD), modified starch (MS) and whey protein concentrate (WPC), Y. lipolytica (Y. lipo) cells, tripolyphosphate (TPP), and sodium erythorbate (SE). The data show a reduction in the water activity value in all treatments. The highest encapsulation yield was found in treatments using MD + TPP + Y. lipo (84.0%) and WPC + TPP + Y. lipo (81.6%). Microencapsulated particles showed a survival rate ranging from 71.61 to 99.83% after 24 h. The treatments WPC + Y. lipo, WPC + SE + Y. lipo, WPC + TPP + Y. lipo, and MD + SE + Y. lipo remained stable for up to 105 days under storage conditions. The treatment WPC + SE + Y. lipo (microencapsulated yeast) was applied in the diet of ruminants due to the greater stability of cell survival. The comparison between the WPC + SE + Y. lipo treatment, wall materials, and the non-microencapsulated yeast showed that the microencapsulated yeast obtained a higher soluble fraction, degradability potential, and release of nutrients.

Health Benefits of Consuming Foods with Bacterial Probiotics, Postbiotics, and Their Metabolites: A Review

Over the years, probiotics have been extensively studied within the medical, pharmaceutical, and food fields, as it has been revealed that these microorganisms can provide health benefits from their consumption. Bacterial probiotics comprise species derived from lactic acid bacteria (LAB) (genus Lactobacillus, Leuconostoc, and Streptococcus), the genus Bifidobacterium, and strains of Bacillus and Escherichia coli, among others. The consumption of probiotic products is increasing due to the current situation derived from the pandemic caused by COVID-19. Foods with bacterial probiotics and postbiotics are premised on being healthier than those not incorporated with them. This review aims to present a bibliographic compilation related to the incorporation of bacterial probiotics in food and to demonstrate through in vitro and in vivo studies or clinical trials the health benefits obtained with their metabolites and the consumption of foods with bacterial probiotics/postbiotics. The health benefits that have been reported include effects on the digestive tract, metabolism, antioxidant, anti-inflammatory, anticancer, and psychobiotic properties, among others. Therefore, developing food products with bacterial probiotics and postbiotics is a great opportunity for research in food science, medicine, and nutrition, as well as in the food industry.

Non-saccharomyces yeast probiotics: revealing relevance and potential

Non-Saccharomyces yeasts are unicellular eukaryotes that play important roles in diverse ecological niches. In recent decades, their physiological and morphological properties have been reevaluated and reassessed, demonstrating the enormous potential they possess in various fields of application. Non-Saccharomyces yeasts have gained relevance as probiotics, and in vitro and in vivo assays are very promising and offer a research niche with novel applications within the functional food and nutraceutical industry. Several beneficial effects have been described, such as antimicrobial and antioxidant activities and gastrointestinal modulation and regulation functions. In addition, several positive effects of bioactive compounds or production of specific enzymes have been reported on physical, mental and neurodegenerative diseases as well as on the organoleptic properties of the final product. Other points to highlight are the multiomics as a tool to enhance characteristics of interest within the industry; as well as microencapsulation offer a wide field of study that opens the niche of food matrices as carriers of probiotics; in turn, non-Saccharomyces yeasts offer an interesting alternative as microencapsulating cells of various compounds of interest.

Microencapsulation of a Commercial Food-Grade Protease by Spray Drying in Cross-Linked Chitosan Particles

In this study, the use of spray-drying technology for encapsulating Flavourzyme® (protease–peptidase complex) was evaluated to overcome the limitations (low encapsulation efficiency and no large-scale production) of other encapsulation processes. To the best of our knowledge, spray drying has not been applied previously for the immobilization of this enzyme. Firstly, bovine serum albumin (BSA), as a model protein, was encapsulated by spray drying in chitosan and tripolyphoshate (TPP) cross-linked-chitosan shell matrices. The results showed that the chitosan–TPP microcapsules provided a high encapsulation efficiency and better protein stability compared to the non-crosslinked chitosan microcapsules. The effect of enzyme concentration and drying temperature were tested during the spray drying of Flavourzyme®. In this regard, an activity yield of 88.0% and encapsulation efficiency of 78.6% were obtained with a concentration of 0.1% (v/v) and an inlet temperature of 130 °C. Flavourzyme®-loaded chitosan microcapsules were also characterized in terms of their size and morphology using scanning electron microscopy and laser diffractometry.

Limosilactobacillus reuteri in Health and Disease

Limosilactobacillus reuteri is a microorganism with valuable probiotic qualities that has been widely employed in humans to promote health. It is a well-studied probiotic bacterium that exerts beneficial health effects due to several metabolic mechanisms that enhance the production of anti-inflammatory cytochines and modulate the gut microbiota by the production of antimicrobial molecules, including reuterin. This review provides an overview of the data that support the role of probiotic properties, and the antimicrobial and immunomodulatory effects of some L. reuteri strains in relation to their metabolite production profile on the amelioration of many diseases and disorders. Although the results discussed in this paper are strain dependent, they show that L. reuteri, by different mechanisms and various metabolites, may control body weight and obesity, improve insulin sensitivity and glucose homeostasis, increase gut integrity and immunomodulation, and attenuate hepatic disorders. Gut microbiota modulation by ingesting probiotic L. reuteri strains could be a promising preventative and therapeutic approach against many diseases and disorders.

Efficacy of the incorporation between self-encapsulation and cryoprotectants on improving the freeze-dried survival of probiotic bacteria

AIMS

This study aimed to improve the viability of probiotic bacteria during freeze-drying by the combination of self-encapsulation and cryoprotectants.

METHODS AND RESULTS

Lactiplantibacillus plantarum VAL6 and Lactobacillus acidophilus VAR1 were exposed to environmental stresses including temperature, pH, and increased CO₂ concentration before performing freeze-drying with the addition of cryoprotectants. The results proved that tested stresses can stimulate the bacteria to synthesize more extracellular polymeric substances to form self-encapsulation that increases their freeze-dried viability. In combination with cryoprotectants to form double-layered microencapsulation, L. plantarum VAL6 stressed at pH 3.5 in combination with whey protein isolate could achieve the highest Improving Cell Viability of 4,361 fold, while L. acidophilus VAR1 stressed at 25^o C in combination with alginate gave a maximum Improving Cell Viability of 73.33 fold.

CONCLUSIONS

The combination of self-encapsulation and cryoprotectants significantly improves the freeze-dried viability of probiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report that uses environmental stress to stimulate EPS synthesis for self-encapsulation formation combined with the addition of cryoprotectants to enhance to the freeze-dried survival of probiotics. This could be a novel approach in improving the viability of probiotic strains for various applications.

Survival of Microencapsulated Lactococcus lactis Subsp. lactis R7 Applied in Different Food Matrices

Survival of Lactococcus lactis subsp. lactis R7, microencapsulated with whey and inulin, was analyzed when added to blueberry juice, milk, and cream. For 28 days, cell viability was evaluated for storage (4 °C), simulated gastrointestinal tract (GIT), and thermal resistance. All matrices demonstrated high cell concentration when submitted to GIT (11.74 and 12 log CFU mL^-1), except for the blueberry juice. The thermal resistance analysis proved the need for microencapsulation, regardless of the food matrix. The results indicate that L. lactis R7 microcapsules have potential for application in different matrices and development of new probiotic products by thermal processing.

Anthocyanin-Colored Microencapsulation Effects on Survival Rate of Lactobacillus rhamnosus GG, Color Stability, and Sensory Parameters in Strawberry Nectar Model

Probiotic microencapsulation is a promising way to produce functional food, while their stability and sensory acceptability still a challenge. This study aims to enhance the functional properties of strawberry (Fragaria × ananassa, cultivar Camarosa) nectar and sensory acceptance using novel anthocyanin-colored microencapsulation of Lactobacillus rhamnosus. Four formulations (F1–F4) of coated materials (alginate, whey protein, and pullulan) integrated with anthocyanin pigment were used for encapsulation. The physical properties of microencapsulated probiotics (size, color, efficiency, stability, and survival rate) and quality parameters of nectar (pH, anthocyanin, and sensory acceptability) during 4 weeks of storage at 4 and 25 °C were evaluated. All formulations exhibited high encapsulation efficiency (> 89%), medium bead size (406–504 μm), and proper color (red color). The microencapsulated cells were stable in simulated gastrointestinal and processing conditions (up 7 log10 CFU mL−1) compared to free cells. F4 (alginate 2% + anthocyanin 0.1% + whey protein 2% + pullulan 2% + cocoa butter 1% + L. rhamnosus GG) showed the greatest viability in nectar during storage (6.72 log10 CFU mL−1/4 °C/4 weeks), while a significant decrease in pH (< 2) and anthocyanin (< 60 mg 100 g−1) was observed in nectar-containing free cells. The sensory scores with a difference-preference test as exploratory and preliminary responses revealed that colored probiotic microcapsules enhanced the sensory characters (up to 4 weeks) and commercially accepted (> 80% agreed) of strawberry nectar. Results demonstrated that anthocyanin-colored alginate-whey protein-pullulan matrix had the potential to enhance probiotic viability in functional nectar without negative impact.

Reuterin-producing Limosilactobacillus reuteri: Optimization of in situ reuterin production in alginate-based filmogenic solutions

Limosilactobacillus reuteri produces reuterin via glycerol anaerobic fermentation. This compound has antimicrobial properties and is used for food preservation purposes. Filmogenic solutions constituted of polysaccharides and glycerol are also employed, however, reuterin synthesis in filmogenic solutions has not yet been reported. Thus, the aim of this study was to optimize the in situ reuterin production by L. reuteri in alginate- and glycerol based-filmogenic solution, evaluating the survival of reuterin-producing bacteria during fermentation. The study consisted of a completely randomized design employing two L. reuteri strains (DSM 20016 and DSM 17938). The filmogenic solutions were obtained using sodium alginate (20 g/L) and two independent variables were studied: glycerol (0–300 mmol/L) and initial biomass of L. reuteri (≅6, 7, and 8 log CFU/mL). The samples were analyzed every 24 h for 72 h of anaerobic fermentation (37 °C). Both L.reuteri strains confirmed the potential for reuterin production and were susceptible to the metabolite produced. The highest reuterin production was achieved using L. reuteri DSM 20016. The initial microbial biomass of 8 log CFU/mL and 100 mmol/L of glycerol increased the reuterin production. However, higher conversion yields from glycerol to reuterin were obtained using 50 mmol/L of substrate.

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L. reuteri strains DSM 20016 and DSM 17938 produce reuterin.

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In situ reuterin production was detected in filmogenic solution.

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Reuterin production varied with initial microbial biomass and glycerol concentration.

Microencapsulation: a pragmatic approach towards delivery of probiotics in gut

Probiotics confer numerous health benefits and functional foods prepared with these microbes own largest markets. However, their viability during transit from gastrointestinal tract is a concerning issue. Microencapsulation of probiotics is a novel technique of major interest to increase their survivability in GIT and food matrices by providing a physical barrier to protect them under harsh conditions. This article contributes the knowledge regarding microencapsulation by discussing probiotic foods, different methods and approaches of microencapsulation, coating materials, their release mechanisms at the target site, and interaction with probiotics, efficiency of encapsulated probiotics, their viability assessment methods, applications in food industry, and their future perspective. In our opinion, encapsulation has significantly got importance in the field of innovative probiotic enriched functional foods development to preserve their viability and long-term survival rate until product expiration date and their passage through gastro-intestinal tract. Previous review work has targeted some aspects of microencapsulation, this article highlights different methods of probiotics encapsulation and coating materials in relation with food matrices as well as challenges faced during applications: Gut microbiota; Lactic acid bacteria; Micro-encapsulation; Stability enhancement; Cell's release, Health benefits.

Pulse Probiotic Superfood as Iron Status Improvement Agent in Active Women-A Review

Active women or women of reproductive age (15–49 years old) have a high risk of suffering from anaemia. Anaemia is not solely caused by iron deficiency, however, the approaches to improve iron status in both cases are greatly related. Improving the iron status of active women can be done by dietary intervention with functional food. This review aims to provide insights about the functional food role to increase iron absorption in active women and the potency of pulse probiotic superfood development in dry matrices. Results showed that the beneficial effect of iron status is significantly improved by the synergic work between probiotic and prebiotic. Furthermore, chickpeas and lentils are good sources of prebiotic and the consumption of pulses are related with 21st century people’s intention to eat healthy food. There are wide possibilities to develop functional food products incorporated with probiotics to improve iron status in active woman.

Effect of Microencapsulation on Survival at Simulated Gastrointestinal Conditions and Heat Treatment of a Non Probiotic Strain, Lactiplantibacillus plantarum 48M, and the Probiotic Strain Limosilactobacillus reuteri DSM 17938

Cells of the probiotic strain Limosilactobacillus reuteri DSM 17938 and of the non-probiotic strain Lactiplantibacillus plantarum 48M were microencapsulated in alginate matrix by emulsion technique. Survival of microorganisms in the microcapsules was tested against gastrointestinal (GI) simulated conditions and heat stress. Results demonstrated that the microencapsulation process improved vitality of Lactiplantibacillus plantarum 48M cells after GI conditions exposure, allowing survival similarly to the probiotic Limosilactobacillus reuteri DSM 17938. Moreover, microencapsulation was able to protect neither Limosilactobacillus reuteri DSM 17938 nor Lactiplantibacillus plantarum 48M cells when exposed to heat treatments. Microencapsulated Limosilactobacillus reuteri DSM 17938 cells were still able to produce reuterin, an antimicrobial agent, as well as free cells.

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.

Viability of Lactobacillus rhamnosus GG in Simulated Gastrointestinal Conditions and After Baking White Pan Bread at Different Temperature and Time Regimes

This study investigated the viability of encapsulated and un-encapsulated (free cell) Lactobacillus rhamnosus GG (LGG) in bread baked at different baking conditions (180 °C for 30 min, 220 °C for 20 min, and 250 °C for 15 min) and in simulated gastrointestinal conditions. The cell was encapsulated either with sodium alginate, singly or in combination with chitosan, cassava starch, and hi-maize resistant starch. There was complete loss of viability of un-encapsulated LGG after baking. Significantly (P < 0.05) higher viability was recorded for LGG encapsulated with sodium alginate + cassava starch + chitosan beads (SCCB) and sodium alginate + hi-maize resistant starch + chitosan beads (SHCB) compared to sodium alginate beads (SAB) and sodium alginate + cassava starch beads (SSB). Lactobacillus rhamnosus GG encapsulated with SHCB gave the highest viability (P < 0.05) after subjection to simulated gastric and intestinal juices. The incorporation of LGG did not have significant (P < 0.05) influence on volume, specific volume, moisture, ash, fat, and fiber contents of bread. The lowest moisture content was obtained at baking condition of 180 °C for 30 min, while the highest value was at 250 °C for 15 min. Baking condition did not cause significant (P > 0.05) change in fat, ash, and carbohydrate content of bread. The encapsulation of LGG with multiple layers of encapsulating materials significantly preserved its viability during baking and in simulated gastrointestinal conditions.

Improved viability of Akkermansia muciniphila by encapsulation in spray dried succinate-grafted alginate doped with epigallocatechin-3-gallate

We explored the possibility of improving the viability of Akkermansia muciniphila by encapsulating it in succinate-grafted alginate doped with epigallocatechin-3-gallate (EGCG). In this study, the determined surface properties of microcapsules and modified materials and the measured viability of probiotics after spray drying showed that the modified sodium alginate made the surfaces of microcapsules smoother and denser during the spray drying, thus preventing damages. EGCG enhanced the antioxidant capacity of probiotics by filling the pores inside microgels. Moreover, we analyzed the long-term storage vitality changes, oxidation resistance, uniformity, particle size and Zeta potential of microcapsules and found that spray-dried modified sodium alginate microcapsules with EGCG showed the better storability and stability. In addition, we experimentally analyzed the resistances of different microcapsules to the gastrointestinal fluid and found that EGCG-modified sodium alginate microcapsules better protected the probiotic activity from gastrointestinal fluid. This study provides a slimming product with industrial application potential.

A Brief Review of Edible Coating Materials for the Microencapsulation of Probiotics

The consumption of probiotics has been associated with a wide range of health benefits for consumers. Products containing probiotics need to have effective delivery of the microorganisms for their consumption to translate into benefits to the consumer. In the last few years, the microencapsulation of probiotic microorganisms has gained interest as a method to improve the delivery of probiotics in the host as well as extending the shelf life of probiotic-containing products. The microencapsulation of probiotics presents several aspects to be considered, such as the type of probiotic microorganisms, the methods of encapsulation, and the coating materials. The aim of this review is to present an updated overview of the most recent and common coating materials used for the microencapsulation of probiotics, as well as the involved techniques and the results of research studies, providing a useful knowledge basis to identify challenges, opportunities, and future trends around coating materials involved in the probiotic microencapsulation.

Growth of Lactobacillus reuteri DSM17938 Under Two Simulated Microgravity Systems: Changes in Reuterin Production, Gastrointestinal Passage Resistance, and Stress Genes Expression Response

Extreme factors such as space microgravity, radiation, and magnetic field differ from those that occur on Earth. Microgravity may induce and select some microorganisms for physiological, metabolic, and/or genetic variations. This study was conducted to determine the effects of simulated microgravity conditions on the metabolism and gene expression of the probiotic bacterium Lactobacillus reuteri DSM17938. To investigate microbial response to simulated microgravity, two devices-the rotating wall vessel (RWV) and the random positioning machine (RPM)-were used. Microbial growth, reuterin production, and resistance to gastrointestinal passage were assessed, and morphological characteristics were analyzed by scanning electron microscopy. The expression of some selected genes that are responsive to stress conditions and to bile salts stress was evaluated through real-time quantitative polymerase chain reaction assay. Monitoring of bacterial growth, cell size, and shape under simulated microgravity did not reveal differences compared with 1 × g controls. On the contrary, an enhanced production of reuterin and a greater tolerance to the gastrointestinal passage were observed. Moreover, some stress genes were upregulated under RWV conditions, especially after 24 h of treatment, whereas RPM conditions seemed to determine a downregulation over time of the same stress genes. These results show that simulated microgravity could alter some physiological characteristics of L. reuteri DSM17938 with regard to tolerance toward stress conditions encountered on space missions and could be useful to elucidate the adaptation mechanisms of microbes to the space environment.

Chitosan Coating Applications in Probiotic Microencapsulation

Nowadays, probiotic bacteria are extensively used as health-related components in novel foods with the aim of added-value for the food industry. Ingested probiotic bacteria must resist gastrointestinal exposure, the food matrix, and storage conditions. The recommended methodology for bacteria protection is microencapsulation technology. A key aspect in the advancement of this technology is the encapsulation system. Chitosan compliments the real potential of coating microencapsulation for applications in the food industry due to its physicochemical properties: positive charges via its amino groups (which makes it the only commercially available water-soluble cationic polymer), short-term biodegradability, non-toxicity and biocompatibility with the human body, and antimicrobial and antifungal actions. Chitosan-coated microcapsules have been reported to have a major positive influence on the survival rates of different probiotic bacteria under in vitro gastrointestinal conditions and in the storage stability of different types of food products; therefore, its utilization opens promising routes in the food industry.

Industrially-Scalable Microencapsulation of Plant Beneficial Bacteria in Dry Cross-Linked Alginate Matrix

Microencapsulation of plant-beneficial bacteria, such as pink pigmented facultative methylotrophs (PPFM), may greatly extend the shelf life of these Gram-negative microorganisms and facilitate their application to crops for sustainable agriculture. A species of PPFM designated Methylobacterium radiotolerans was microencapsulated in cross-linked alginate microcapsules (CLAMs) prepared by an innovative and industrially scalable process that achieves polymer cross-linking during spray-drying. PPFM survived the spray-drying microencapsulation process with no significant loss in viable population, and the initial population of PPFM in CLAMs exceeded 1010 CFU/g powder. The PPFM population in CLAMs gradually declined by 4 to 5 log CFU/g over one year of storage. The extent of alginate cross-linking, modulated by adjusting the calcium phosphate content in the spray-dryer feed, did not influence cell viability after spray-drying, viability over storage, or dry particle size. However, particle size measurements and light microscopy of aqueous CLAMs suggest that enhanced crosslinking may limit the release of encapsulated bacteria. This work demonstrates an industrially scalable method for producing alginate-based inoculants that may be suitable for on-seed or foliar spray applications.

Evaluation of Streptococcus thermophilus IFFI 6038 Microcapsules Prepared Using an Ultra-fine Particle Processing System

Microencapsulation technology has the potential to protect probiotics and to deliver them to the gut, and extrusion is one of the most commonly used methods. However, the rather large diameters of 1~5 mm produced tend to cause oral grittiness and result in low compliance. In this article, Streptococcus thermophilus IFFI 6038 (IFFI 6038) microcapsules were prepared using an ultra-fine particle processing system (UPPS) previously developed by this research group. IFFI 6038 suspension was pumped by a peristaltic pump to the feeding inlet nozzle and then dispersed into micro-droplets by a rotating disk, followed by solidification. Trehalose (16%) was used as a cryoprotectant to protect IFFI 6038 from damage by lyophilization used in the process. Alginate (3%) resulted in IFFI 6038 microcapsules with a median particle diameter (d ₅₀) of 29.32 ± 0.12 μm and a span value of 1.00 ± 0.02, indicating uniform particle size distribution. To evaluate the potential of microencapsulation in protecting IFFI 6038 from the gastric conditions, the viable counts of IFFI 6038 following incubation of IFFI 6038 microcapsules in simulated gastric juices for 120 min were determined and compared with those of free IFFI 6038. The stability of microencapsulated IFFI 6038 upon storage for 3 months at 4°C and 25°C, respectively, was also determined. The results showed that microcapsules prepared by UPPS protected IFFI 6038 from gastric conditions. The results from a rat diarrhea model showed that microcapsules prepared by the UPPS method were able to effectively improve the diarrhea conditions in rats.

Edible Films and Coatings as Carriers of Living Microorganisms: A New Strategy Towards Biopreservation and Healthier Foods

Edible films and coatings have been extensively studied in recent years due to their unique properties and advantages over more traditional conservation techniques. Edible films and coatings improve shelf life and food quality, by providing a protective barrier against physical and mechanical damage, and by creating a controlled atmosphere and acting as a semipermeable barrier for gases, vapor, and water. Edible films and coatings are produced using naturally derived materials, such as polysaccharides, proteins, and lipids, or a mixture of these materials. These films and coatings also offer the possibility of incorporating different functional ingredients such as nutraceuticals, antioxidants, antimicrobials, flavoring, and coloring agents. Films and coatings are also able to incorporate living microorganisms. In the last decade, several works reported the incorporation of bacteria to confer probiotic or antimicrobial properties to these films and coatings. The incorporation of probiotic bacteria in films and coatings allows them to reach the consumers' gut in adequate amounts to confer health benefits to the host, thus creating an added value to the food product. Also, other microorganisms, either bacteria or yeast, can be incorporated into edible films in a biocontrol approach to extend the shelf life of food products. The incorporation of yeasts in films and coatings has been suggested primarily for the control of the postharvest disease. This work provides a comprehensive review of the use of edible films and coatings for the incorporation of living microorganisms, aiming at the biopreservation and probiotic ability of food products.

Microencapsulation increases survival of the probiotic Lactobacillus plantarum IS-10506, but not Enterococcus faecium IS-27526 in a dynamic, computer-controlled in vitro model of the upper gastrointestinal tract

AIM

To test the effect of microencapsulation on the survival of two probiotic strains isolated from Dadih, Indonesian fermented buffalo milk, in a dynamic, computer-controlled in vitro model of the upper gastrointestinal (GI) tract (TIM-1), simulating human adults.

METHODS AND RESULTS

Free or microencapsulated probiotics, Lactobacillus plantarum IS-10506 or Enterococcus faecium IS-27526, resuspended in milk were studied for survival in the complete TIM-1 system (stomach + small intestine) or in the gastric compartment of TIM-1 only. Hourly samples collected after the ileal-caecal valve or after the pylorus were plated on MRS agar (for Lactobacillus) or S&B agar (for Enterococcus). Survival of the free cells after transit through the complete TIM-1 system was on average for the E. faecium and L. plantarum 15·0 and 18·5% respectively. Survival of the microencapsulated E. faecium and L. plantarum was 15·7 and 84·5% respectively. The free cells were further assessed in only the gastric compartment of TIM-1. E. faecium and L. plantarum showed an average survival of 39 and 32%, respectively, after gastric passage.

CONCLUSION

There is similar sensitivity to gastric acid as well as survival after complete upper GI tract transit of free cells, but microencapsulation only protected L. plantarum.

SIGNIFICANCE AND IMPACT OF STUDY

Survival of microencapsulated L. plantarum IS-10506 is increased compared to free cells in a validated in vitro model of the upper GI tract. It increases its use as an ingredient of functional foods.

Potential functional bakery products as delivery systems for prebiotics and probiotics health enhancers

Several health benefits have been associated to probiotics and prebiotics, most of these are involved in the regulation of the host's gut microbiome. Their incorporation to diverse food products has been done to develop potential functional foods. In the case of bakery products, their incorporation has been seen to improve several technological parameters such as volume, specific volume, texture along with sensorial parameters such as flavor and aroma. Scientific literature in this topic has been divided in three main research branches: nutrition, physical quality and sensory analyzes, however, studies rarely cover all of them. Due to the harsh thermal stress during baking, sourdough technology along with microencapsulation of probiotics, has been studied as an alternative to enhance its nutritional values and increase cell viability, though in few occasions. The potential functional baked goods have maintained acceptable physical characteristics and sensorial acceptability, while in some cases an improvement is seen due to the effect of probiotics and prebiotics. The results obtained from several studies done, have shown the viability of developing functional bakery products by applying prebiotics or probiotics. This could be used as an encouragement for more research to be done in this topic.

Probiotic Incorporation in Edible Films and Coatings: Bioactive Solution for Functional Foods

Nowadays, the consumption of food products containing probiotics, has increased worldwide due to concerns regarding healthy diet and wellbeing. This trend has received a lot of attention from the food industries, aiming to produce novel probiotic foods, and from researchers, to improve the existing methodologies for probiotic delivery or to develop and investigate new possible applications. In this sense, edible films and coatings are being studied as probiotic carriers with many applications. There is a wide variety of materials with film-forming ability, possessing different characteristics and subsequently affecting the final product. This manuscript aims to provide significant information regarding probiotics and active/bioactive packaging, to review applications of probiotic edible films and coatings, and to discuss certain limitations of their use as well as the current legislation and future trends.

Differential enumeration of subpopulations in concentrated frozen and lyophilized cultures of Lactobacillus delbrueckii ssp. bulgaricus

Differential enumeration of subpopulations in concentrated frozen and lyophilized cultures of Lactobacillus delbrueckii ssp. bulgaricus ND02 derived from 2 propagation procedures was determined. The subpopulations consisted of 3 categories (physiological states): viable cells capable of forming colonies on agar plates (VC+), viable cells incapable of forming colonies on agar plates (VC-), widely referred to as viable but nonculturable (VBNC) cells, and nonviable or dead cells (NVC). Counts of VC+ were recorded using a conventional plate count procedure. A fluorescent vital staining procedure that discriminates between viable (VC+ and VC-) and NVC cells was used to determine the number of viable and nonviable cells. Both propagation procedures had 2 variables: in procedure (P)1, the propagation medium was rich in yeast extract (4.0%) and the pH was maintained at 5.7; in P2, the medium was devoid of yeast extract and the pH was maintained at 5.1. The results showed that post-propagation operations-concentration of cells by centrifugation and subsequent freezing or lyophilization of cell concentrate-induced different degrees of transience from VC+ to VC- states in cells derived from P1 and P2. Compared with cells derived from P2, cells from P1 were more labile to stress associated with centrifugation, freezing, and lyophilization, as revealed by differential counting.

Preparation of Acid-Resistant Microcapsules with Shell-Matrix Structure to Enhance Stability of Streptococcus Thermophilus IFFI 6038

Microencapsulation is an effective technology used to protect probiotics against harsh conditions. Extrusion is a commonly used microencapsulation method utilized to prepare probiotics microcapsules that is regarded as economical and simple to operate. This research aims to prepare acid-resistant probiotic microcapsules with high viability after freeze-drying and optimized storage stability. Streptococcus thermophilus IFFI 6038 (IFFI 6038) cells were mixed with trehalose and alginate to fabricate microcapsules using extrusion. These capsules were subsequently coated with chitosan to obtain chitosan-trehalose-alginate microcapsules with shell-matrix structure. Chitosan-alginate microcapsules (without trehalose) were also prepared using the same method. The characteristics of the microcapsules were observed by measuring the freeze-dried viability, acid resistance, and long-term storage stability of the cells. The viable count of IFFI 6038 in the chitosan-trehalose-alginate microcapsules was 8.34 ± 0.30 log CFU g^-1 after freeze-drying (lyophilization), which was nearly 1 log units g^-1 greater than the chitosan-alginate microcapsules. The viability of IFFI 6038 in the chitosan-trehalose-alginate microcapsules was 6.45 ± 0.09 log CFU g^-1 after 120 min of treatment in simulated gastric juices, while the chitosan-alginate microcapsules only measured 4.82 ± 0.22 log CFU g^-1 . The results of the long-term storage stability assay indicated that the viability of IFFI 6038 in chitosan-trehalose-alginate microcapsules was higher than in chitosan-alginate microcapsules after storage at 25 °C. Trehalose played an important role in the stability of IFFI 6038 during storage. The novel shell-matrix chitosan-trehalose-alginate microcapsules showed optimal stability and acid resistance, demonstrating their potential as a delivery vehicle to transport probiotics.