Encapsulation of Lactobacillus acidophilus in moist-heat-resistant multilayered microcapsules

Encapsulation of Probiotics within Double/Multiple Layer Beads/Carriers: A Concise Review

An increased demand for natural products nowadays most specifically probiotics (PROs) is evident since it comes in conjunction with beneficial health effects for consumers. In this regard, it is well known that encapsulation could positively affect the PROs' viability throughout food manufacturing and long-term storage. This paper aims to analyze and review various double/multilayer strategies for encapsulation of PROs. Double-layer encapsulation of PROs by electrohydrodynamic atomization or electrospraying technology has been reported along with layer-by-layer assembly and water-in-oil-in-water (W1/O/W2) double emulsions to produce multilayer PROs-loaded carriers. Finally, their applications in food products are presented. The resistance and viability of loaded PROs to mechanical damage, during gastrointestinal transit and shelf life of these trapping systems, are also described. The PROs encapsulation in double- and multiple-layer coatings combined with other technologies can be examined to increase the opportunities for new functional products with amended functionalities opening a novel horizon in food technology.

Emerging Multiscale Biofabrication Approaches for Bacteriotherapy

Bacteriotherapy is emerging as a strategic and effective approach to treat infections by providing putatively harmless bacteria (i.e., probiotics) as antagonists to pathogens. Proper delivery of probiotics or their metabolites (i.e., post-biotics) can facilitate their availing of biomaterial encapsulation via innovative manufacturing technologies. This review paper aims to provide the most recent biomaterial-assisted strategies proposed to treat infections or dysbiosis using bacteriotherapy. We revised the encapsulation processes across multiscale biomaterial approaches, which could be ideal for targeting different tissues and suit diverse therapeutic opportunities. Hydrogels, and specifically polysaccharides, are the focus of this review, as they have been reported to better sustain the vitality of the live cells incorporated. Specifically, the approaches used for fabricating hydrogel-based devices with increasing dimensionality (D)-namely, 0D (i.e., particles), 1D (i.e., fibers), 2D (i.e., fiber meshes), and 3D (i.e., scaffolds)-endowed with probiotics, were detailed by describing their advantages and challenges, along with a future overlook in the field. Electrospinning, electrospray, and 3D bioprinting were investigated as new biofabrication methods for probiotic encapsulation within multidimensional matrices. Finally, examples of biomaterial-based systems for cell and possibly post-biotic release were reported.

Proteolysis and therapeutic potential of bioactive peptides derived from Cheddar cheese

Cheddar cheese-derived bioactive peptides are considered a potential component of functional foods. A positive impact of bioactive peptides on diet-related chronic, non-communicable diseases, like obesity, cardiovascular diseases, and diabetes, has been observed. Bioactive peptides possess multifunctional therapeutic potentials, including antimicrobial, immunomodulatory, antioxidant, enzyme inhibitory effects, anti-thrombotic, and phyto-pathological activities against various toxic compounds. Peptides can regulate human immune, gastrointestinal, hormonal, and neurological responses, which play an integral role in the deterrence and treatment of certain diseases like cancer, osteoporosis, hypertension, and other health disorders, as described in the present review. This review summarizes the categories of the Cheddar cheese-derived bioactive peptides, their general characteristics, physiological functions, and possible applications in healthcare.

Development of probiotic loaded multilayer microcapsules incorporated into dissolving microneedles for potential improvement treatment of vulvovaginal candidiasis: A proof of concept study

Vulvovaginal candidiasis (VVC) is a vaginal infection caused by abnormal growth of Candida sp., especially Candida albicans, in the vaginal mucosa. A shift in vaginal microbiota is prominent in VVC. The presence of Lactobacillus plays a vital role in maintaining vaginal health. However, several studies have reported resistance of Candida sp. against azoles drugs, which is recommended as VVC treatment. The use of L. plantarum as a probiotic would be an alternative to treat VVC. In order to exert their therapeutic activity, the probiotics needed to remain viable. Multilayer double emulsion was formulated to obtain L. plantarum loaded microcapsules (MCs), thus improving its viability. Furthermore, a vaginal drug delivery system using dissolving microneedles (DMNs) for VVC treatment was developed for the first time. These DMNs showed sufficient mechanical and insertion properties, dissolved rapidly upon insertion, facilitating probiotic release. All formulations proved non-irritating, non-toxic, and safe to apply on the vaginal mucosa. Essentially, the DMNs could inhibit the growth of Candida albicans up to 3-fold than hydrogel and patch dosage forms in ex vivo infection model. Therefore, this study successfully developed the formulation of L. plantarum-loaded MCs with multilayer double emulsion and its combination in DMNs for vaginal delivery to treat VVC.

Polysaccharides, proteins, and their complex as microencapsulation carriers for delivery of probiotics: A review on carrier types and encapsulation techniques

Probiotics provide several benefits for humans, including restoring the balance of gut bacteria, boosting the immune system, and aiding in the management of certain conditions such as irritable bowel syndrome and lactose intolerance. However, the viability of probiotics may undergo a significant reduction during food storage and gastrointestinal transit, potentially hindering the realization of their health benefits. Microencapsulation techniques have been recognized as an effective way to improve the stability of probiotics during processing and storage and allow for their localization and slow release in intestine. Although, numerous techniques have been employed for the encapsulation of probiotics, the encapsulation techniques itself and carrier types are the main factors affecting the encapsulate effect. This work summarizes the applications of commonly used polysaccharides (alginate, starch, and chitosan), proteins (whey protein isolate, soy protein isolate, and zein) and its complex as the probiotics encapsulation materials; evaluates the evolutions in microencapsulation technologies and coating materials for probiotics, discusses their benefits and limitations, and provides directions for future research to improve targeted release of beneficial additives as well as microencapsulation techniques. This study provides a comprehensive reference for current knowledge pertaining to microencapsulation in probiotics processing and suggestions for best practices gleaned from the literature.

Encapsulating biocontrol bacteria with starch as a safe and edible biopolymer to alleviate plant diseases: A review

Healthy foods with few artificial additives are in high demand among consumers. Preserving conventional pesticides, frequently used as chemicals to control phytopathogens, is challenging. Therefore, we proposed an innovative approach to protect agricultural products in this review. Biocontrol bacteria are safe alternatives with low stability and low efficiency in the free-form formulation. The encapsulation technique for covering active compounds (e.g., antimicrobials) represents a more efficient protection technology because encapsulation causes the controlled release of bioactive materials and reduces the application doses. Of the biopolymers able to form a capsule, starch exhibits several advantages, such as its ready availability, cost-effectively, edible, colorless, and tasteless. Nevertheless, the poor mechanical properties of starch can be improved with other edible biopolymers. In addition, applying formulations incorporated with more than one antimicrobial material offers synergistic effects. This review presented the starch-based capsules used to enclose antimicrobial agents as effective tools against phytopathogens.

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.

Microbial-Based Products to Control Soil-Borne Pathogens: Methods to Improve Efficacy and to Assess Impacts on Microbiome

Microbial-based products (either as biopesticide or biofertilizers) have a long history of application, though their use is still limited, mainly due to a perceived low and inconsistent efficacy under field conditions. However, their efficacy has always been compared to chemical products, which have a completely different mechanism of action and production process, following the chemical paradigm of agricultural production. This paradigm has also been applied to regulatory processes, particularly for biopesticides, making the marketing of microbial-based formulations difficult. Increased knowledge about bioinocula behavior after application to the soil and their impact on soil microbiome should foster better exploitation of microbial-based products in a complex environment such as the soil. Moreover, the multifunctional capacity of microbial strains with regard to plant growth promotion and protection should also be considered in this respect. Therefore, the methods utilized for these studies are key to improving the knowledge and understanding of microbial-based product activity and improving their efficacy, which, from farmers' point of view, is the parameter to assess the usefulness of a treatment. In this review, we are thus addressing aspects related to the production and formulation process, highlighting the methods that can be used to evaluate the functioning and impact of microbial-based products on soil microbiome, as tools supporting their use and marketing.

Effect of the molecular structure and mechanical properties of plant-based hydrogels in food systems to deliver probiotics: an updated review

Probiotic products' economic value and market popularity have grown over time as more people discover their health advantages and adopt healthier lifestyles. There is a significant societal and cultural interest in these products known as foods or medicines. Products containing probiotics that claim to provide health advantages must maintain a "minimum therapeutic" level (107-106 CFU/g) of bacteria during their entire shelf lives. Since probiotic bacteria are susceptible to degradation and reduction by physical and chemical conditions (including acidity, natural antimicrobial agents, nutrient contents, redox potential, temperature, water activity, the existence of other bacteria, and sensitivity to metabolites), the most challenging problem for a food manufacturer is ensuring probiotic cells' survival and stability enhancement throughout the manufacturing stage. Currently, the use of plant-based hydrogels for improved and targeted probiotic delivery has gained substantial attention as a potential approach to overcoming the mentioned restrictions. To achieve the best possible results from hydrogels, whether used as a coating for encapsulated probiotics (with the goal of stomach protection) or as carriers for direct encapsulation of live microorganisms should be applied kind of procedures that ensure high bacterial survival during hydrogels application. This paper summarizes polysaccharides, proteins, and lipid-based hydrogels as carriers of encapsulated probiotics in delivery systems, reviews their structures, analyzes their advantages and disadvantages, studies their mechanical characteristics, and draws comparisons between them. The discussion then turns to how the criterion affects encapsulation, applications, and future possibilities.

Improvement of Moist Heat Resistance of Ascorbic Acid through Encapsulation in Egg Yolk–Chitosan Composite: Application for Production of Highly Nutritious Shrimp Feed Pellets

Simple Summary

Egg yolk (EY) is an excellent supplement for aquatic animals and has good food functionality. According to the high lipid content in EY, it was, for the first time, used in combination with chitosan (CS) to encapsulate the ascorbic acid (AA) to minimize the loss of AA during exposure to feed processing and seawater. The microcapsules’ production yield, EE, and moist heat resistance were evaluated. One selected encapsulated AA was fortified in shrimp feed. The AA retention in feed processing and seawater was evaluated. Both EE and production yields of the microcapsules were relatively high compared to other reports. Moist heat resistance capability of the encapsulated AA was up to 82%. EY was essential in moist heat protection, while CS significantly improved the microcapsules’ production yield, EE, and morphology. The loss of AA in feed processing and seawater was remarkably improved by 16 folds compared to the unencapsulated AA. The microcapsules showed high potential application for foods and aquatic feed to protect heat-labile and hydro-soluble substances.

Abstract

Egg yolk (EY) is an excellent supplement for aquatic animals and has good technofunctionality. Ascorbic acid (AA) is a potent bioactive substance and is essentially added to shrimp feed; however, it is drastically lost in both feed processing and in rearing environments. In this study, AA was microencapsulated in an EY–chitosan (CS) composite. The encapsulated vitamin was then mixed into a shrimp feed mixture to form pelleted feed via twin-screw extrusion. The effects of the EY/AA ratio and the amount of CS on moist heat resistance, production yield, encapsulation efficiency (EE), and morphology of microcapsules were investigated. The molecular interaction of the microcapsule components was analyzed by FTIR. The size and size distribution of the microcapsules were determined using a laser diffraction analyzer. The microstructure was evaluated by SEM. The physical properties of the microcapsule-fortified pelleted feed were determined. The AA retention at each step of feed processing and during exposure to seawater was evaluated. The results showed that the microcapsules had a spherical shape with an average diameter of ~6.0 μm. Decreasing the EY/AA ratio significantly improved the production yield, EE, and morphology of the microcapsules. EY proved to be the key component for moist heat resistance, while CS majorly improved the production yield, EE, and morphology of the microcapsules. The microcapsules showed no adverse impact on feed properties. The loss of AA in food processing and seawater was remarkably improved. The final content of the encapsulated AA remaining in shrimp feed was 16-fold higher than that of the unencapsulated AA.

Biopolymer-Based Multilayer Microparticles for Probiotic Delivery to Colon

The potential health benefits of probiotics may not be realized because of the substantial reduction in their viability during food storage and gastrointestinal transit. Microencapsulation has been successfully utilized to improve the resistance of probiotics to critical conditions. Owing to the unique properties of biopolymers, they have been prevalently used for microencapsulation of probiotics. However, majority of microencapsulated products only contain a single layer of protection around probiotics, which is likely to be inferior to more sophisticated approaches. This review discusses emerging methods for the multilayer encapsulation of probiotic using biopolymers. Correlations are drawn between fabrication techniques and the resultant microparticle properties. Subsequently, multilayer microparticles are categorized based on their layer designs. Recent reports of specific biopolymeric formulations are examined regarding their physical and biological properties. In particular, animal models of gastrointestinal transit and disease are highlighted, with respect to trials of multilayer microencapsulated probiotics. To conclude, novel materials and approaches for fabrication of multilayer structures are highlighted.

Microencapsulating Alginate-Based Polymers for Probiotics Delivery Systems and Their Application

Probiotics exhibit many health benefits and a great potential for broad applications in pharmaceutical fields, such as prevention and treatment of gastrointestinal tract diseases (irritable bowel syndrome), prevention and therapy of allergies, certain anticancer effects, and immunomodulation. However, their applications are limited by the low viability and metabolic activity of the probiotics during processing, storage, and delivery in the digestive tract. To overcome the mentioned limitations, probiotic delivery systems have attracted much attention. This review focuses on alginate as a preferred polymer and presents recent advances in alginate-based polymers for probiotic delivery systems. We highlight several alginate-based delivery systems containing various types of probiotics and the physical and chemical modifications with chitosan, cellulose, starch, protein, fish gel, and many other materials to enhance their performance, of which the viability and protective mechanisms are discussed. Withal, various challenges in alginate-based polymers for probiotics delivery systems are traced out, and future directions, specifically on the use of nanomaterials as well as prebiotics, are delineated to further facilitate subsequent researchers in selecting more favorable materials and technology for probiotic delivery.

Microencapsulation as a Noble Technique for the Application of Bioactive Compounds in the Food Industry: A Comprehensive Review

The use of natural food ingredients has been increased in recent years due to the negative health implications of synthetic ingredients. Natural bioactive compounds are important for the development of health-oriented functional food products with better quality attributes. The natural bioactive compounds possess different types of bioactivities, e.g., antioxidative, antimicrobial, antihypertensive, and antiobesity activities. The most common method for the development of functional food is the fortification of these bioactive compounds during food product manufacturing. However, many of these natural bioactive compounds are heat-labile and less stable. Therefore, the industry and researchers proposed the microencapsulation of natural bioactive compounds, which may improve the stability of these compounds during processing and storage conditions. It may also help in controlling and sustaining the release of natural compounds in the food product matrices, thus, providing bioactivity for a longer duration. In this regard, several advanced techniques have been explored in recent years for microencapsulation of bioactive compounds, e.g., essential oils, healthy oils, phenolic compounds, flavonoids, flavoring compounds, enzymes, and vitamins. The efficiency of microencapsulation depends on various factors which are related to natural compounds, encapsulating materials, and encapsulation process. This review provides an in-depth discussion on recent advances in microencapsulation processes as well as their application in food systems.

Electrosprayed Ethyl Cellulose Core-Shell Microcapsules for the Encapsulation of Probiotics

Electrosprayed ethyl cellulose core–shell microcapsules were produced for the encapsulation of probiotic Bifidobacterium animalis subsp. lactis (Bifido). Ethyl cellulose (ETC) was used as a shell material with different core compounds (concentrated Bifido, Bifido–maltodextrin and Bifido–glycerol). The core–shell microcapsules have an average diameter between 3 µm and 15 µm depending on the core compounds, with a distinct interface that separates the core and the shell structure. The ETC microcapsules displayed relatively low water activity (aw below 0.20) and relatively high values of viable cells (10⁹–10¹¹ CFU/g), as counted post-encapsulation. The effect of different core compounds on the stability of probiotics cells over time was also investigated. After four weeks at 30 °C and 40% RH the electrospray encapsulated samples containing Bifido–glycerol in the core showed a loss in viable cells of no more than 3 log loss CFU/g, while the non-encapsulated Bifido lost about 7.57 log CFU/g. Overall, these results suggest that the viability of the Bifido probiotics encapsulated within the core–shell ETC electrosprayed capsules can be extended, despite the fact that the shell matrix was prepared using solvents that typically substantially reduce their viability.

Alginate/Fish Gelatin-Encapsulated Lactobacillus acidophilus: A Study on Viability and Technological Quality of Bread during Baking and Storage

In the present study, Lactobacillus acidophilus LA-5 was microencapsulated in sodium alginate, followed by fish gelatin coating (0.5, 1.5, and 3%). The survival of L. acidophilus in bread before and after encapsulation in alginate/fish gelatin during the baking and 7-day storage was investigated. Moreover, the effect of alginate/fish gelatin-encapsulated L. acidophilus on the technological properties of bread (hardness, staling rate, water content, oven spring, specific volume, and internal texture structure) was evaluated. Compared with control (free bacteria), encapsulated L. acidophilus in alginate/fish gelatin showed an increase in the viability of bread until 2.49 and 3.07 log CFU/g during baking and storage, respectively. Good viability of (10⁶ CFU/g) for probiotic in encapsulated L. acidophilus in alginate/fish gelatin (1.5 and 3%, respectively) after 4-day storage was achieved. Fish gelatin as a second-layer carrier of the bacteria had a positive effect on improving the technical quality of bread. Furthermore, the staling rate of bread containing encapsulated L. acidophilus alginate/fish gelatin 0.5, 1.5, and 3% decreased by 19.5, 25.8, and 31.7%, respectively. Overall, the findings suggested encapsulation of L. acidophilus in alginate/fish gelatin capsule had great potential to improve probiotic bacteria’s survival during baking and storage and to serve as an effective bread enhancer.

Starch-based materials encapsulating food ingredients: Recent advances in fabrication methods and applications

Encapsulation systems have gained significant interest in designing innovative foods, as they allow for the protection and delivery of food ingredients that have health benefits but are unstable during processing, storage and in the upper gastrointestinal tract. Starch is widely available, cheap, biodegradable, edible, and easy to be modified, thus highly suitable for the development of encapsulants. Much efforts have been made to fabricate various types of porous starch and starch particles using different techniques (e.g. enzymatic hydrolysis, aggregation, emulsification, electrohydrodynamic process, supercritical fluid process, and post-processing drying). Such starch-based systems can load, protect, and deliver various food ingredients (e.g. fatty acids, phenolic compounds, carotenoids, flavors, essential oils, irons, vitamins, probiotics, bacteriocins, co-enzymes, and caffeine), exhibiting great potentials in developing foods with tailored flavor, nutrition, sensory properties, and shelf-life. This review surveys recent advances in different aspects of starch-based encapsulation systems including their forms, manufacturing techniques, and applications in foods.

Resistant Starch-Based Edible Coating Composites for Spray-Dried Microencapsulation of Lactobacillus acidophilus, Comparative Assessment of Thermal Protection, In Vitro Digestion and Physicochemical Characteristics

Polysaccharides have excellent potential as food-grade coating materials for microencapsulation in pro- and prebiotics-based functional food industry. In this study, potato, maize, and rice resistant starches composite coatings with D-mannose, maltodextrin, and whey protein concentrate were prepared for the spray-dried microencapsulation of Lactobacillus acidophilus KLDS 1.1003. Assessment of different polysaccharide coatings to enhance the longevity of probiotics at high temperatures of spray-drying process, storage, and targeted delivery in the gastrointestinal tract were the key objectives of the present study. The highest microencapsulation efficiencies were shown by maize (95.80%) and potato (94.30%) resistant starches. Similarly, maize resistant starch (MRS)-based composites provided the highest thermal resistance, with Tg 38.77 ± 1.10–93.13 ± 0.81 °C and showed the least 2.1 log cycles viability loss in simulated GI tract. Viability losses during storage were in the following order: control > RRS > PRS > MRS, and the inactivation rate of the microencapsulated cells followed the first-order kinetics (R2 = 0.9264–0.9918). The resistant starch-based spray-dried microcapsules possessed 27.00 ± 0.03 to 52.28 ± 1.02 µm size range and SEM micrographs showed a unified smooth surface without cracks and ruptures. These findings will expand the potential use of natural food-grade coatings in functional foods and allied industries involving spray-dried products.

Functional properties of Lactobacillus casei C24 improved by microencapsulation using multilayer double emulsion

To provide their health effect, probiotics need to maintain their viability, adhere to the intestinal epithelium, and colonize it without losing their probiotic properties. In the present study, Lactobacillus casei was encapsulated in a double emulsion and then coated with alginate and chitosan using the layer-by-layer electrostatic deposition technique. The survival rate and functional properties of L. casei (cholesterol assimilation, surface hydrophobicity, auto-aggregation, and co-aggregation) were evaluated after the freeze-drying process and during the transit through the simulated gastrointestinal tract. Reservoir type multilayer microcapsules with a small particle size (6.2-12.2 μm) were obtained. Freeze-dried microcapsules maintained the initial cell count (9.4 log UFC/g) without affecting its functional properties. The resistance of L. casei cells to the conditions of salivary, gastric, and intestinal digestion was noticeably improved when increasing the number of layers in the microcapsules, especially when they were coated with alginate and chitosan. The alginate-chitosan layers provided additional protection to L. casei cell membranes, substantially preserving the cholesterol assimilation ability, surface hydrophobicity, auto-aggregation, and co-aggregation of L. casei after simulated in vitro digestion. This encapsulation method not only guarantees the presence of the probiotic in the gastrointestinal tract, but it does not lose its probiotic properties and ensures that it exerts its probiotic effect.

Microstructures of encapsulates and their relations with encapsulation efficiency and controlled release of bioactive constituents: A review

Vitamins, peptides, essential oils, and probiotics are examples of health beneficial constituents, which are nevertheless heat-sensitive and possess poor chemical stability. Various encapsulation methods have been applied to protect these constituents against thermal and chemical degradations. Encapsulates prepared by different methods and/or at different conditions exhibit different microstructures, which in turn differently influence the encapsulation efficiency as well as retention of encapsulated core materials. This review provides a summary of various microstructures resulted from the use of selected encapsulation methods or systems, namely, spray coating; co-extrusion; emulsion-, micelle-, and liposome-based; coacervation; and ionic gelation encapsulation, at different conditions. Subsequent effects of the different microstructures on encapsulation efficiency and retention of encapsulated core materials are mentioned and discussed. Encapsulates having compact microstructures resulted from the use of low-surface tension and low-viscosity encapsulants, high-stability encapsulation systems, lower loads of core materials to total solids of encapsulants and appropriate solidification conditions have proved to exhibit higher encapsulation efficiencies and better retention of encapsulated core materials. Encapsulates with hollow, dent, shrunken microstructures or thinner walls resulted from inappropriate solidification conditions and higher loads of core materials, on the other hand, possess lower encapsulation efficiencies and protection capabilities. Encapsulates having crack, blow-hole or porous microstructures resulted from the use of high-viscosity encapsulants and inappropriate solidification conditions exhibit the lowest encapsulation efficiencies and poorest protection capabilities. Compact microstructures and structures formed between ionic biopolymers could be used to regulate the release of encapsulated cores.

Preparation and Evaluation of Microcapsules Encapsulating Royal Jelly Sieve Residue: Flavor and Release Profile

This study aimed to improve the flavor of royal jelly residue via microencapsulation technology using Arabic gum and gelatin as wall materials. This microencapsulation technology showed a good encapsulation yield of 85.71 ± 2.84% and encapsulation efficiency of 92.34 ± 3.17%. The intact structures of the microcapsules were observed using optical and scanning electron microscopes. The results of the simulated gastrointestinal digestion proved that the microcapsules were well-tolerated in the gastric environment (a release rate of 32.95 ± 2.34%). Both electronic nose and electronic tongue evaluations showed that microencapsulation improved the sensory index of the royal jelly sieve residue. After microencapsulation, the astringency, bitterness, and irritant odors of the royal jelly residue were reduced. Simultaneously, the release rate in the intestine was 98.77 ± 1.91%, which demonstrated that microencapsulation would not prevent the human body from absorbing the royal jelly. The results from this study are expected to facilitate the development of mild flavor products made from royal jelly.

Potential of Nanonutraceuticals in Increasing Immunity

Nutraceuticals are defined as foods or their extracts that have a demonstrably positive effect on human health. According to the decision of the European Food Safety Authority, this positive effect, the so-called health claim, must be clearly demonstrated best by performed tests. Nutraceuticals include dietary supplements and functional foods. These special foods thus affect human health and can positively affect the immune system and strengthen it even in these turbulent times, when the human population is exposed to the COVID-19 pandemic. Many of these special foods are supplemented with nanoparticles of active substances or processed into nanoformulations. The benefits of nanoparticles in this case include enhanced bioavailability, controlled release, and increased stability. Lipid-based delivery systems and the encapsulation of nutraceuticals are mainly used for the enrichment of food products with these health-promoting compounds. This contribution summarizes the current state of the research and development of effective nanonutraceuticals influencing the body's immune responses, such as vitamins (C, D, E, B12, folic acid), minerals (Zn, Fe, Se), antioxidants (carotenoids, coenzyme Q10, polyphenols, curcumin), omega-3 fatty acids, and probiotics.

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.

Preparation and characterization of double-coated probiotic bacteria via a fluid-bed process: a case study on Lactobacillus reuteri

In this research, a specific fluidized bed coater, Wurster, was used to double-coat Lactobacillus reuteri. The first layer of coating was shellac (16, 17 and 18% w/v) and sodium alginate (0.5, 1 and 1.5% w/v). The microcapsules coated by 1% sodium alginate showed the highest relative survival of bacteria (11.1%) after 1 h in simulated gastric conditions (pH 2) and was, therefore, selected as the first layer of the microcapsules. Chitosan (0.5, 1 and 1.5% w/v), and arabic gum (1.5, 3 and 6% w/v) were used for the second layer. The best second layer was determined on the basis of relative survival of bacteria after acidic (simulated gastric conditions) and heating (80 °C for 15 and 30 min) examinations. The results showed that the relative survival of bacteria in microcapsules with a second coat of 1% w/v chitosan was higher than the others in both acidic (11.6%) and heating (7.31% at 15 min and 0.63% at 30 min) conditions.

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.

Delivery to the gut microbiota: A rapidly proliferating research field

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

Use of Electrohydrodynamic Processing for Encapsulation of Sensitive Bioactive Compounds and Applications in Food

The use of vitamins, polyphenolic antioxidants, omega-3 polyunsaturated fatty acids (PUFAs), and probiotics for the fortification of foods is increasing. However, these bioactive compounds have low stability and need to be protected to avoid deterioration in the food system itself or in the gastrointestinal tract. For that purpose, efficient encapsulation of the compounds may be required. Spray drying is one of the most commonly used encapsulation techniques in the food industry, but it uses high temperature, which can lead to decomposition of the bioactive compounds. Recently, alternative technologies such as electrospraying and electrospinning have received increasing attention. This review presents the principles of electrohydrodynamic processes for the production of nano-microstructures (NMSs) containing bioactive compounds. It provides an overview of the current use of this technology for encapsulation of bioactive compounds and discusses the future potential of the technology. Finally, the review discusses advanced microscopy techniques to study the morphology of NMSs.

Use of gelatin and gum arabic for microencapsulation of probiotic cells from Lactobacillus plantarum by a dual process combining double emulsification followed by complex coacervation

The objectives of this study were i) to microencapsulate probiotic cells of Lactobacillus plantarum through a dual process consisting of emulsification followed by complex coacervation using gelatin and gum arabic, ii) to characterize the lyophilized microcapsules, iii) to evaluate their behavior in simulated in vitro gastrointestinal conditions and iv) to evaluate the survival of microencapsulated probiotic cells during 45 days of storage at 8 °C, 25 °C and -18 °C. The optimized conditions for complex coacervation consisted of a 50:50 biopolymer ratio and pH = 4.0. Emulsification was followed by complex coacervation using gelatin and gum arabic. The microcapsules presented dispersibility of 0.183 ± 0.17 g·mL^-1, moisture content of 4.5%, water activity of 0.34 ± 0.03 and hygroscopicity of 9.20 ± 0.43 g of absorbed water per 100 g. Their size ranged from 66.07 ± 3.04 μm to 105.66 ± 3.24 μm. Viability of the encapsulated L. plantarum cells was 8.6 log CFU·g^-1 and the encapsulation efficiency was 97.78%. After in vitro simulation of gastrointestinal conditions, viability of the encapsulated cells was 80.4% whereas it was only 25.0% for the free cells at 37 °C. Probiotic cell viability was maintained during storage at 8 °C and - 18 °C for 45 days.

Electrospinning and electrospraying technologies for food applications

Electrospinning and electrospraying are versatile techniques for the production of nano- to micro-scale fibers and particles. Over the past 2 decades, significant progresses have been made to advance the fundamental understandings of these electrohydrodynamic processes. Researchers have investigated different polymeric and non-polymeric substrates for producing submicron electrospun/electrosprayed materials of unique morphologies and physicochemical properties. This chapter provides an overview on the basic principles of electrospinning and electrospraying, highlighting the effects of key processing and solution parameters. Electrohydrodynamic phenomena of edible substrates, including polysaccharides (xanthan, alginate, starch, cyclodextrin, pullulan, dextran, modified celluloses, and chitosan), proteins (zein, what gluten, whey protein, soy protein, gelatin, etc.), and phospholipids are reviewed. Selected examples are presented on how ultrafine fibers and particles derived from these substrates are being exploited for food and nutraceutical applications. Finally, the challenges and opportunities of the electrostatic methods are discussed.

Development of Novel Microparticles for Effective Delivery of Thymol and Lauric Acid to Pig Intestinal Tract

Antibiotics have been widely supplemented in feeds at subtherapeutic concentrations to prevent postweaning diarrhea and increase the overall productivity of pigs. However, the emergence of antimicrobial-resistant bacteria worldwide has made it urgent to minimize the use of in-feed antibiotics. The development of promising alternatives to in-feed antibiotics is crucial for maintaining the sustainability of swine production. Both medium-chain fatty acids (MCFA) and essential oils exhibit great potential to postweaning diarrhea; however, their direct inclusion has compromised efficacy because of several factors including low stability, poor palatability, and low availability in the lower gut. Therefore, the objective of this study was to develop a formulation of microparticles to deliver a model of essential oil (thymol) and MCFA (lauric acid). The composite microparticles were produced by the incorporation of starch and alginate through a melt-granulation process. The release of thymol and lauric acid from the microparticles was in vitro determined using simulated salivary fluid (SSF), simulated gastric fluid (SGF), and simulated intestinal fluid (SIF), consecutively. The microparticles prepared with 2% alginate solution displayed a slow release of thymol and lauric acid in the SSF (21.2 ± 2.3%; 36 ± 1.1%), SGF (73.7 ± 6.9%; 54.8 ± 1.7%), and SIF (99.1 ± 1.2%; 99.1 ± 0.6%), respectively, whereas, the microparticles without alginate showed a rapid release of thymol and lauric acid from the SSF (79.9 ± 11.8%; 84.9 ± 9.4%), SGF (92.5 ± 3.5%; 75.8 ± 5.9%), and SIF (93.3 ± 9.4%; 93.3 ± 4.6%), respectively. The thymol and lauric acid in the developed microparticles with or without alginate both exhibited excellent stabilities (>90%) during being stored at 4 °C for 12 weeks and after being stored at room temperature for 2 weeks. These results evidenced that the approach developed in the present study could be potentially employed to deliver thymol and lauric acid to the lower gut of pigs, although further in vivo investigations are necessary to validate the efficacy of the microparticles.

Preparation and characterization of alginate and gelatin microcapsules containing Lactobacillus rhamnosus

This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM), moisture content, Fourier Transform Infrared Spectrometry (FTIR), thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 109 CFU/g) was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 105 CFU/g after 4 months of storage at 8 oC.