Optimization of Alginate-Whey Protein Isolate Microcapsules for Survivability and Release Behavior of Probiotic Bacteria

Effect of Encapsulation of Lactobacillus casei in Alginate-Tapioca Flour Microspheres Coated with Different Biopolymers on the Viability of Probiotic Bacteria

To realize the health benefits of probiotic bacteria, they must withstand processing and storage conditions and remain viable after use. The encapsulation of these probiotics in the form of microspheres containing tapioca flour as a prebiotic and vehicle component in their structure or shell affords symbiotic effects that improve the survival of probiotics under unfavorable conditions. Microencapsulation is one such method that has proven to be effective in protecting probiotics from adverse conditions while maintaining their viability and functionality. The aim of the work was to obtain high-quality microspheres that can act as carriers of Lactobacillus casei bacteria and to assess the impact of encapsulation on the viability of probiotic microorganisms in alginate microspheres enriched with a prebiotic (tapioca flour) and additionally coated with hyaluronic acid, chitosan, or gelatin. The influence of the composition of microparticles on the physicochemical properties and the viability of probiotic bacteria during storage was examined. The optimal composition of microspheres was selected using the design of experiments using statistical methods. Subsequently, the size, morphology, and cross-section of the obtained microspheres, as well as the effectiveness of the microsphere coating with biopolymers, were analyzed. The chemical structure of the microspheres was identified by using Fourier-transform infrared spectrophotometry. Raman spectroscopy was used to confirm the success of coating the microspheres with the selected biopolymers. The obtained results showed that the addition of tapioca flour had a positive effect on the surface modification of the microspheres, causing the porous structure of the alginate microparticles to become smaller and more sealed. Moreover, the addition of prebiotic and biopolymer coatings of the microspheres, particularly using hyaluronic acid and chitosan, significantly improved the survival and viability of the probiotic strain during long-term storage. The highest survival rate of the probiotic strain was recorded for alginate-tapioca flour microspheres coated with hyaluronic acid, at 5.48 log CFU g-1. The survival rate of L. casei in that vehicle system was 89% after storage for 30 days of storage.

Preparation of a Lactobacillus rhamnosus ATCC 7469 microencapsulated-lactulose synbiotic and its effect on equol production

Equol is a highly active product of soy isoflavones produced by specific bacteria in the human or animal colon. However, equol production is influenced by differences in the gut flora carried by the body. Our previous research has shown that a synbiotic preparation comprising the probiotic Lactobacillus rhamnosus ATCC 7469 and the prebiotic lactulose can enhance equol production by modulating the intestinal flora. Nevertheless, the harsh environment of the gastrointestinal tract limits this capability by diminishing the number of probiotics reaching the colon. Microencapsulation of probiotics is an effective strategy to enhance their viability. In this study, probiotic gel microspheres (SA-S-CS) were prepared using an extrusion method, with sodium alginate (SA) and chitosan (CS) serving as the encapsulating materials. Scanning electron microscopy (SEM) was employed to observe the surface morphology and the internal distribution of bacteria within the microcapsules. The structural characteristics of the microcapsules were investigated using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Furthermore, the thermal stability, storage stability, probiotic viability post-simulated gastrointestinal fluid treatment, and colon release rate were examined. Finally, the impact of probiotic microencapsulation on promoting equol production by the synbiotic preparation was assessed. The results indicated that the microcapsules exhibited a spherical structure with bacteria evenly distributed on the inner surface. Studies on thermal and storage stability showed that the number of viable cells in the probiotic microcapsule group significantly increased compared to the free probiotic group. Gastrointestinal tolerance studies revealed that after in vitro simulated gastrointestinal digestion, the amount of viable cells in the microcapsules was 7 log10 CFU g-1, demonstrating good gastrointestinal tolerance. Moreover, after incubation in simulated colonic fluid for 150 min, the release rate of probiotics reached 93.13%. This suggests that chitosan-coated sodium alginate microcapsules can shield Lactobacillus rhamnosus ATCC 7469 from the gastrointestinal environment, offering a novel model for synbiotic preparation to enhance equol production.

Synthesis and characterization of ion-induced sodium alginate/soy protein isolate microgels for the controlled release

In this study, sodium alginate/ soy protein isolate (SPI) microgels cross-linked by various divalent cations including Cu2+, Ba2+, Ca2+, and Zn2+ were fabricated. Cryo-scanning electron microscopy observations revealed distinctive structural variations among the microgels. In the context of gastric pH conditions, the degree of shrinkage of the microgels followed the sequence of Ca2+ > Ba2+ > Cu2+ > Zn2+. Meanwhile, under intestinal pH conditions, the degree of swelling was ranked as Zn2+ > Ca2+ > Ba2+ > Cu2+. The impact of these variations was investigated through in vitro digestion studies, revealing that all microgels successfully delayed the release of β-carotene within the stomach. Within the simulated intestinal fluid, the microgel cross-linked with Zn2+ exhibited an initial burst release, while those cross-linked with Cu2+, Ba2+, or Ca2+ displayed a sustained release pattern. This research underscores the potential of sodium alginate/SPI microgels cross-linked with different divalent cations as efficient controlled-release delivery systems.

Enhancing storage and gastroprotective viability of Lactiplantibacillus plantarum encapsulated by sodium caseinate-inulin-soy protein isolates composites carried within carboxymethyl cellulose hydrogel

Probiotics are subjected to various edible coatings, especially proteins and polysaccharides, which serve as the predominant wall materials, with ultrasound, a sustainable green technology. Herein, sodium caseinate, inulin, and soy protein isolate composites were produced using multi-frequency ultrasound and utilized to encapsulateLactiplantibacillus plantarumto enhance its storage, thermal, and gastrointestinal viability. The physicochemical analyses revealed that the composites with 5 % soy protein isolate treated with ultrasound at 50 kHz exhibited enough repulsion forces to maintain stability, pH resistance, and the ability to encapsulate larger particles and possessed the highest encapsulation efficiency (95.95 %). The structural analyses showed changes in the composite structure at CC, CH, CO, and amino acid residual levels. Rheology, texture, and water-holding capacity demonstrated the production of soft hydrogels with mild chewing and gummy properties, carried the microcapsules without coagulation or sedimentation. Moreover, the viability attributes ofL. plantarumevinced superior encapsulation, protecting them for at least eight weeks and against heat (63 °C), reactive oxidative species (H2O2), and GI conditions.

Fabrication and characterization of salidroside W/O/W emulsion with sodium alginate

Salidroside (Sal), the main bioactive substance in Rhodiola rosea, is a promising functional food component with a wide range of pharmacological effects, but its biological activity is challenging to sustain due to its short half-life, low oral bioavailability, and susceptibility to environmental factors. The aim of this study was to investigate the effect of sodium alginate (SA) concentration on the construction of W/O/W emulsion in the protection of Sal. With the escalation of SA concentrations, the range of droplet size distribution was smaller and the droplets were more uniform. When the concentration of SA was 2 %, the average droplet size reached 9.1 ± 0.1 μm, and the encapsulation efficiency of Sal was 77.8 ± 1.8 %. Moreover, the double emulsion with 2 % SA was the most stable for 28 days at 4 °C since the oil droplets were embedded in the network structure of SA.

Protective Effects of Laminaria japonica Polysaccharide Composite Microcapsules on the Survival of Lactobacillus plantarum during Simulated Gastrointestinal Digestion and Heat Treatment

To improve probiotics' survivability during gastrointestinal digestion and heat treatment, Lactobacillus plantarum was microencapsulated by spray-drying using Laminaria japonica polysaccharide/sodium caseinate/gelatin (LJP/SC/GE) composites. Thermogravimetry and differential scanning calorimetry results revealed that the denaturation of LJP/SC/GE microcapsules requires higher thermal energy than that of SC/GE microcapsules, and the addition of LJP may improve thermal stability. Zeta potential measurements indicated that, at low pH of the gastric fluid, the negatively charged LJP attracted the positively charged SC/GE, helping to maintain an intact microstructure without disintegration. The encapsulation efficiency of L. plantarum-loaded LJP/SC/GE microcapsules reached about 93.4%, and the survival rate was 46.9% in simulated gastric fluid (SGF) for 2 h and 96.0% in simulated intestinal fluid (SIF) for 2 h. In vitro release experiments showed that the LJP/SC/GE microcapsules could protect the viability of L. plantarum in SGF and release probiotics slowly in SIF. The cell survival of LJP/SC/GE microcapsules was significantly improved during the heat treatment compared to SC/GE microcapsules and free cells. LJP/SC/GE microcapsules can increase the survival of L. plantarum by maintaining the lactate dehydrogenase and Na+-K+-ATPase activity. Overall, this study demonstrates the great potential of LJP/SC/GE microcapsules to protect and deliver probiotics in food and pharmaceutical systems.

Encapsulation of Active Substances in Natural Polymer Coatings

Already used in the food, pharmaceutical, cosmetic, and agrochemical industries, encapsulation is a strategy used to protect active ingredients from external degradation factors and to control their release kinetics. Various encapsulation techniques have been studied, both to optimise the level of protection with respect to the nature of the aggressor and to favour a release mechanism between diffusion of the active compounds and degradation of the barrier material. Biopolymers are of particular interest as wall materials because of their biocompatibility, biodegradability, and non-toxicity. By forming a stable hydrogel around the drug, they provide a 'smart' barrier whose behaviour can change in response to environmental conditions. After a comprehensive description of the concept of encapsulation and the main technologies used to achieve encapsulation, including micro- and nano-gels, the mechanisms of controlled release of active compounds are presented. A panorama of natural polymers as wall materials is then presented, highlighting the main results associated with each polymer and attempting to identify the most cost-effective and suitable methods in terms of the encapsulated drug.

Properties and stability of Lactiplantibacillus plantarum AB6-25 and Saccharomyces boulardii T8-3C single and double-layered microcapsules containing Na-alginate and/or demineralized whey powder with lactobionic acid

The present study aimed to enhance the survivability of the encapsulated biocomposites of Lactiplantibacillus plantarum AB6-25 and Saccharomyces boulardii T8-3C within the gastrointestinal system (GIS) and during storage period. AB6-25 and T8-3C were individually co-encapsulated using either lactobionic acid (LBA) in Na-alginate (ALG)/demineralized whey powder (DWP) or solely potential probiotics in ALG microcapsules. Free probiotic cells were utilized as the control group. Both microcapsules and free cells underwent freeze-drying. The encapsulation and freeze-drying efficiency of core materials were evaluated. The protective effect of encapsulation on the probiotics was examined under simulated GIS conditions and during storage at either 25 °C or 4 °C. Additionally, the microcapsules underwent analysis using fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscope (SEM). Encapsulation and freeze-drying processes were carried out efficiently in all groups (88.46 %-99.13 %). SEM revealed that the microcapsules possessed a spherical and homogeneous structure, with sizes ranging from 3 to 10 μm. ALG/DWP and LBA presence in the microcapsule structure was confirmed through FTIR, XRD analysis indicated the formation of a new composite. Over 180 days, all microcapsule groups stored at 4 °C maintained their therapeutic dosage viability. However, after four months, microcapsules stored at 25 °C exhibited a decline in yeast survivability below the therapeutic threshold. Experimental groups demonstrated better viability under simulated GIS conditions compared to the control. These findings suggest the potential use of microencapsulated probiotics as a food supplement and indicate that microcapsule groups containing AB6-25 and T8-3C stored at 4 °C can be preserved for six months.

New perspective on protein-based microcapsules as delivery vehicles for sensitive substances: A review

Sensitive substances have attracted wide attention due to their rich functional activities, such as antibiosis activities, antioxidant activities and prevent disease, etc. However, the low stability of sensitive substances limits their bioavailability and functional activities. Protein-based microcapsules can encapsulate sensitive substances to improve their adverse properties due to their good stability, strong emulsifying ability and wide source. Therefore, it is necessary to fully elaborate and summarize protein-based microcapsules to maximize their potential benefits in nutritional interventions. The focus of this review is to highlight the classification of protein-based microcapsules. In addition, the principles, advantages and disadvantages of preparation methods for protein-based microcapsules are summarized. Some novel preparation methods for protein-based microcapsules are also emphasized. Moreover, the mechanism of protein-based microcapsules that release sensitive substances in vitro is elucidated and summarized. Furthermore, the applications of protein-based microcapsules are outlined. Protein-based microcapsules can effectively encapsulate sensitive substances, which improve their bioavailability, and provide protective effects during storage and gastrointestinal digestion. In addition, microcapsules can improve the sensory quality of food and enhance its stability. The performance of protein-based microcapsules for delivering sensitive substances is influenced by factors such as protein type, the ratio between protein ratio and the other wall material, the preparation process, etc. Future research should focus on the new composite protein-based microcapsule delivery system, which can be applied to in vivo research and have synergistic effects and precise nutritional functions. In summary, protein-based microcapsules have broader research prospects in the functional foods and nutrition field.

Protein-polysaccharide based double network microbeads improves stability of Bifidobacterium infantis ATCC 15697 in a gastro-Intestinal tract model (TIM-1)

Microencapsulation of probiotics is a main technique employed to improve cell survival in gastrointestinal tract (GIT). The present study investigated the impact of utilizing proteins i.e. Whey Protein Isolates (WPI), Pea Protein Isolates (PPI) or (WPI + PPI) complex based microbeads as encapsulating agents on the encapsulation efficiency (EE), diameter, morphology along with the survival and viability of Bifidobacterium infantis ATCC 15697. Results revealed that WPI + PPI combination had the highest EE% of the probiotics up to 94.09 % and the smoothest surface with less visible holes. WPI based beads revealed lower EE% and smaller size than PPI based ones. In addition, WPI based beads showed rough surface with visible signs of cracks, while PPI beads showed dense surfaces with pores and depressions. In contrast, the combination of the two proteins resulted in compact and smooth beads with less visible pores/wrinkles. The survival in gastrointestinal tract (GIT) was observed through TNO in-vitro gastrointestinal model (TIM-1) and results illustrated that all microbeads shrank in gastric phase while swelled in intestinal phase. In addition, in-vitro survival rate of free cells was very low in gastric phase (18.2 %) and intestinal phase (27.5 %). The free cells lost their viability after 28 days of storage (2.66 CFU/mL) with a maximum log reduction of 6.76, while all the encapsulated probiotic showed more than 106-7 log CFU/g viable cell. It was concluded that encapsulation improved the viability of probiotics in GIT and utilization of WPI + PPI in combination provided better protection to probiotics.

Effect of Molecules' Physicochemical Properties on Whey Protein/Alginate Hydrogel Rheology, Microstructure and Release Profile

The encapsulation of molecules with different physicochemical properties (theophylline, blue dextran, salicylic acid and insulin) in whey protein (WP) and alginate (ALG) microparticles (MP) for oral administration was studied. MP based on WP/ALG were prepared by a cold gelation technique and coated with WP solution after reticulation. Molecules influenced polymer solution viscosity and elasticity, resulting in differences regarding encapsulation efficiency (from 23 to 100%), MP structure and swelling (>10%) and in terms of pH tested. Molecule release was due to diffusion and/or erosion of MP and was very dependent on the substance encapsulated. All the loaded MP were successfully coated, but variation in coating thickness (from 68 to 146 µm) and function of the molecules encapsulated resulted in differences in molecule release (5 to 80% in 1 h). Gel rheology modification, due to interactions between WP, ALG, calcium and other substances, was responsible for the highlighted differences. Measuring rheologic parameters before extrusion and reticulation appeared to be one of the most important aspects to study in order to successfully develop a vector with optimal biopharmaceutical properties. Our vector seems to be more appropriate for anionic high-molecular-weight substances, leading to high viscosity and elasticity and to MP enabling gastroresistance and controlled release of molecules at intestinal pH.

Advances in polysaccharides for probiotic delivery: Properties, methods, and applications

Probiotics are essential to improve the health of the host, whereas maintaining the viability of probiotics in harsh environments remains a challenge. Polysaccharides have non-toxicity, excellent biocompatibility, and outstanding biodegradability, which can protect probiotics by forming a physical barrier and show a promising prospect for probiotic delivery. In this review, we summarize polysaccharides commonly used for probiotic microencapsulation and introduce the microencapsulation technologies, including extrusion, emulsion, spray drying, freeze drying, and electrohydrodynamics. We discuss strategies for better protection of probiotics and introduce the applications of polysaccharides-encapsulated probiotics in functional food, oral formulation, and animal feed. Finally, we propose the challenges of polysaccharides-based delivery systems in industrial production and application. This review will help provide insight into the advances and challenges of polysaccharides in probiotic delivery.

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.

FolE gene expression for folic acid productivity from optimized and characterized probiotic Lactobacillus delbrueckii

BACKGROUND

Lactobacillus delbrueckii was one of the most common milk lactic acid bacterial strains (LAB) which characterized as probiotic with many health influencing properties.

RESULTS

Among seven isolates, KH1 isolate was the best producer of folic acid with 100 µg/ml after 48 h of incubation; FolE gene expression after 24 h of incubation was in the highest value in case of KH1 with three folds. Lactose was the best carbon source for this KH1, besides the best next isolates KH80 and KH98. The selected three LAB isolates were identified through 16S rDNA as Lactobacillus delbrueckii. These three isolates have high tolerance against acidic pH 2-3; they give 45, 10, and 22 CFUs at pH 3, besides 9, 6, and 4 CFUs at pH2, respectively. They also have resistance against elevated bile salt range 0.1-0.4%. KH1 recorded 99% scavenging against 97.3% 1000 µg/ml ascorbic acid. Docking study exhibits the binding mode of folic acid which exhibited an energy binding of - 8.65 kcal/mol against DHFR. Folic acid formed four Pi-alkyl, Pi-Pi, and Pi-sigma interactions with Ala9, Ile7, Phe34, and Ile60. Additionally, folic acid interacted with Glu30 and Asn64 by three hydrogen bonds with 1.77, 1.76, and 1.96 Å.

CONCLUSION

LAB isolates have probiotic properties, antioxidant activity, and desired organic natural source for folic acid supplementation that improve hemoglobin that indicated by docking study interaction.

Application of Encapsulation Strategies for Probiotics: From Individual Loading to Co-Encapsulation

Consumers are increasingly showing a preference for foods whose nutritional and therapeutic value has been enhanced. Probiotics are live microorganisms, and their existence is associated with a number of positive effects in humans, as there are many and well-documented studies related to gut microbiota balance, the regulation of the immune system, and the maintenance of the intestinal mucosal barrier. Hence, probiotics are widely preferred by consumers, causing an increase in the corresponding food sector. As a consequence of this preference, food industries and those involved in food production are strongly interested in the occurrence of probiotics in food, as they have proven beneficial effects on human health when they exist in appropriate quantities. Encapsulation technology is a promising technique that aims to preserve probiotics by integrating them with other materials in order to ensure and improve their effectiveness. Encapsulated probiotics also show increased stability and survival in various stages related to their processing, storage, and gastrointestinal transit. This review focuses on the applications of encapsulation technology in probiotics in sustainable food production, including controlled release mechanisms and encapsulation techniques.

Probiotic Encapsulation: Bead Design Improves Bacterial Performance during In Vitro Digestion

The stability and release properties of all bioactive capsules are strongly related to the composition of the wall material. This study aimed to evaluate the effect of the wall materials during the encapsulation process by ionotropic gelation on the viability of Lactobacillus fermentum K73, a lactic acid bacterium that has hypocholesterolemia probiotic potential. A response surface methodology experimental design was performed to improve bacterial survival during the synthesis process and under simulated gastrointestinal conditions by tuning the wall material composition (gelatin 25% w/v, sweet whey 8% v/v, and sodium alginate 1.5% w/v). An optimal mixture formulation determined that the optimal mixture must contain a volume ratio of 0.39/0.61 v/v sweet whey and sodium alginate, respectively, without gelatin, with a final bacterial concentration of 9.20 log10 CFU/mL. The mean particle diameter was 1.6 ± 0.2 mm, and the experimental encapsulation yield was 95 ± 3%. The INFOGEST model was used to evaluate the survival of probiotic beads in gastrointestinal tract conditions. Upon exposure to in the vitro conditions of oral, gastric, and intestinal phases, the encapsulated cells of L. fermentum decreased only by 0.32, 0.48, and 1.53 log10 CFU/mL, respectively, by employing the optimized formulation, thereby improving the survival of probiotic bacteria during both the encapsulation process and under gastrointestinal conditions compared to free cells. Beads were characterized using SEM and ATR-FTIR techniques.

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.

Membrane Emulsification as an Emerging Method for Lacticaseibacillus rhamnosus GG® Encapsulation

Techniques capable of producing small-sized probiotic microcapsules with high encapsulation yields are of industrial and scientific interest. In this study, an innovative membrane emulsification system was investigated in the production of microcapsules containing Lacticaseibacillus rhamnosus GG® (Lr), sodium alginate (ALG), and whey protein (WPI), rice protein (RPC), or pea protein (PPC) as encapsulating agents. The microcapsules were characterized by particle size distribution, optical microscopy, encapsulation yield, morphology, water activity, hygroscopicity, thermal properties, Fourier-transform infrared spectroscopy (FTIR), and probiotic survival during in vitro simulation of gastrointestinal conditions. The innovative encapsulation technique resulted in microcapsules with diameters varying between 18 and 29 μm, and encapsulation yields > 93%. Combining alginate and whey, rice, or pea protein improved encapsulation efficiency and thermal properties. The encapsulation provided resistance to gastrointestinal fluids, resulting in high probiotic viability at the end of the intestinal phase (> 7.18 log CFU g-1). The proposed encapsulation technology represents an attractive alternative to developing probiotic microcapsules for future food applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11947-023-03099-w.

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.

Microencapsulation of Probiotics with Soy Protein Isolate and Alginate for the Poultry Industry

Many probiotic products, with properly selected microorganisms, may not be effective for the intended purpose due to the low tolerance of microorganisms to gastrointestinal digestion. The microencapsulation seems to be one of the most promising techniques to protect probiotics against adverse environmental conditions. Therefore, the aim of this work was the design of soy protein isolate-alginate microcapsules for the encapsulation of probiotics for the poultry industry by the water-in-oil emulsion technique. To this end, the strain Ligilactobacillus salivarius CRL2217, with the ability to bind wheat germ agglutinin (WGA) on its surface and protect intestinal epithelial cells from the cytotoxicity of the glycoprotein, was used as model microorganism. Several parameters were varied in order to find the better conditions for microencapsulation: oil source and nature, SPI and sodium alginate concentration, stirring equipment and time for emulsion formation, CaCl2 concentration, and absence or presence of stirring after the addition of the CaCl2 solution. The survival of entrapped cells to a simulated gastric digestion and their survival and release during simulated intestinal digestion were also investigated. The obtained particles effectively protected L. salivarius CRL2217 from the proteolytic activity and low pH present in the gastric environment. Besides, their content was released in contact with a simulated intestinal juice, as viable counts and binding of WGA after a simulated intestinal digestion revealed. This work paves the way for the design of probiotic supplements for poultry including gastrointestinal digestion-susceptible bacteria.

Producing mixed-soy protein adsorption layers on alginate microgels to controlled-release β-carotene

In this study, the effects of soy protein isolate (SPI) on the morphology, encapsulation efficiency, storage stability, swelling behavior, and in vitro digestion behavior of calcium alginate (CA) microgels were investigated. CA and calcium alginate-SPI (CAS) microgels with encapsulated β-carotene were prepared by extruding a mixture of alginate and SPI using a co-extrusion technique, followed by cross-linking with Ca²⁺. All microgels exhibited homogeneous sizes and spherical shapes, and CAS microgels showed high levels of protein loading efficiency. The encapsulation efficiency and storage stability of β-carotene within CAS microgels were higher than those within CA microgels. The introduction of SPI into CAS microgels resulted in a higher degree of gel size shrinkage in gastric fluid and a lower degree of swelling in intestinal fluid compared to CA microgels. In vitro digestion was conducted to investigate the effects of the addition of SPI on the release behavior of CA and CAS microgels. Results obtained showed that CAS microgels were more resistant to simulated gastric fluid than CA microgels. Cryo-scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) observations indicated that the release behavior was dependent on the porosity of the CA and CAS microgels, and the porosity was influenced by the concentration of SPI. This study showed that the introduction of SPI to CA microgels can lead to the development of an effective controlled release delivery system.

Microencapsulation of Lactobacillus plantarum with enzymatic hydrolysate of soybean protein isolate for improved acid resistance and gastrointestinal survival in vitro

This study aimed to improve the acid resistance effect of Lactobacillus plantarum through microencapsulation with enzymatic hydrolysate of soybean protein isolate (EHSPI) and modified phospholipid. Response surface methodology was adopted to establish the optimal microencapsulation technology of L. plantarum, while coating characters were evaluated. Through response surface methodology, the optimal conditions were obtained as follows based on microencapsulation efficiency: the ratio of bacteria/EHSPI 1:1.83, EHSPI content 4.01%, modified phospholipid content 11.41%. The results of digestion in vitro showed that after passing through the simulated gastric fluid (SGF), the L. plantarum was released and reached 3.55 × 108 CFU/mL in the simulated intestinal fluid. Meanwhile, the surviving bacteria number of control significantly decreased to 2.63 × 104 CFU/mL (P < 0.05) at 120 min in SGF. In sum, the acid resistance and survival of L. plantarum were improved in SGF in vitro, through the microencapsulation technology based on EHSPI.

Improvement in the probiotic efficacy of Bacillus subtilis E20-stimulates growth and health status of white shrimp, Litopenaeus vannamei via encapsulation in alginate and coated with chitosan

The aim of this study was to increase the efficacy of probiotic Bacillus subtilis E20 by encapsulating the probiotic in alginate and coating it with chitosan. The protective effect was evaluated by firstly ensuring the viability of encapsulated probiotics in simulated gastrointestinal fluid (SGF) and simulated intestinal fluid (SIF) conditions and then at different storage temperatures. In addition, the encapsulated probiotic was incorporated into the diet to improve the growth performance and health status of white shrimp, Litopenaeus vannamei. B. subtilis E20 has the ability to survive in SGF when encapsulated in 1.5-2% alginate and coated with 0.4% chitosan. Furthermore, viability increased significantly in SIF compared to the probiotic encapsulated in 1% alginate and coated with 0.4% chitosan and the non-encapsulated probiotic. Longer storage time and adverse conditions affected probiotics' survival, which was improved by the encapsulation with significantly higher viability than the non-encapsulated probiotic at different temperatures and storage duration. Encapsulation of B. subtilis E20 and dietary administration at 10⁷ CFU kg^-1 decreased shrimp mortality after a Vibrio infection, thereby improving shrimp's disease resistance, while the non-encapsulated probiotic required 10⁹ CFU kg^-1 to achieve better resistance. Although the best results of growth performance, immune response, and disease resistance against Vibrio alginolyticus were found in the shrimp fed with the diets supplemented with encapsulated probiotic at >10⁸ CFU kg^-1, shrimp's growth performance and health status improved after being fed 10⁷ CFU kg^-1 encapsulated probiotic for 56 days. Together, the results of this study prove that encapsulation could improve the viability of probiotic in different gastrointestinal conditions and adverse storage temperatures. Overall, lower concentrations of encapsulated probiotic B. subtilis E20 (10⁷ CFU kg^-1) was able to increase the growth performance and health status of shrimp.

Layer-by-Layer Coating of Single-Cell Lacticaseibacillus rhamnosus to Increase Viability Under Simulated Gastrointestinal Conditions and Use in Film Formation

Probiotics and prebiotics are widely used as functional food ingredients. Viability of probiotics in the food matrix and further in the digestive system is still a challenge for the food industry. Different approaches were used to enhance the viability of probiotics including microencapsulation and layer-by-layer cell coating. The of aim of this study was to evaluate the viability of coated Lacticaseibacillus rhamnosus using a layer-by-layer (LbL) technique with black seed protein (BSP) extracted from Nigella sativa defatted seeds cakes (NsDSC), as a coating material, with alginate, inulin, or glucomannan, separately, and the final number of coating layers was 3. The viable cell counts of the plain and coated L. rhamnosus were determined under sequential simulated gastric fluid (SGF) for 120 min and simulated intestinal fluid (SIF) for 180 min. Additionally, the viability after exposure to 37, 45, and 55°C for 30 min was also determined. Generally, the survivability of coated L. rhamnosus showed significant (p ≤ 0.05) improvement (<4, 3, and 1.5 logs reduction for glucomannan, alginate and inulin, respectively) compared with plain cells (∼6.7 log reduction) under sequential exposure to SGF and SIF. Moreover, the cells coated with BSP and inulin showed the best protection for L. rhamnosus under high temperatures. Edible films prepared with pectin with LbL-coated cells showed significantly higher values in their tensile strength (TS) of 50% and elongation at the break (EB) of 32.5% than pectin without LbL-coated cells. The LbL technique showed a significant protection of probiotic cells and potential use in food application.

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 of a Pseudomonas Strain (VUPF506) in Alginate-Whey Protein-Carbon Nanotubes and Next-Generation Sequencing Identification of This Strain

Alginate is a common agent used for microencapsulation; however, the formed capsule is easily damaged. Therefore, alginate requires blending with other biopolymers to reduce capsule vulnerability. Whey protein is one polymer that can be incorporated with alginate to improve microcapsule structure. In this study, three different encapsulation methods (extrusion, emulsification, and spray drying) were tested for their ability to stabilize microencapsulated Pseudomonas strain VUPF506. Extrusion and emulsification methods enhanced encapsulation efficiency by up to 80% and gave the best release patterns over two months. A greenhouse experiment using potato plants treated with alginate-whey protein microcapsules showed a decrease in Rhizoctonia disease intensity of up to 70%. This is because whey protein is rich in amino acids and can serve as a resistance induction agent for the plant. In this study, the use of CNT in the ALG-WP system increased the rooting and proliferation and reduced physiological complication. The results of this study showed that the technique used in encapsulation could have a significant effect on the efficiency and persistence of probiotic bacteria. Whole genome sequence analysis of strain VUPF506 identified it as Pseudomonas chlororaphis and revealed some genes that control pathogens.

Algae-derived hydrocolloids in foods: applications and health-related issues

Hydrocolloids are a class of food additives with broad applications in the food industry to develop structure in food ingredients. Hydrocolloids can be synthetic, plant-based, or animal-based. Increasing consumer awareness has led to the use of natural food ingredients derived from natural sources, making algae-derived hydrocolloids more appealing nowadays. Algae-derived hydrocolloids such as carrageenan, agar, and alginate are widely used in the food industry as thickening, gelling, and emulsifying agents. Carrageenans are sulfated polysaccharides with diverse structural specificities. The safety of carrageenan use in the food industry has been widely debated recently due to the reported pro-inflammatory activities of carrageenan and the probable digestion of carrageenan by the gut microbiota to generate pro-inflammatory oligosaccharides. In contrast, both agar and alginate are primarily nontoxic, and generally no dispute regarding the use of the same in food ingredients. This review provides an overview of the algae industry, the food additives, the algae-derived hydrocolloids, the applications of algae-derived hydrocolloids in food industries, health-related studies, and other sectors, along with future perspectives. Even though differences of opinion exist in the use of carrageenan, it is continued to be used by the food industry and will be used until suitable alternatives are available. In summary, algal hydrocolloids are 'label-friendly' and considered a safe option against synthetic additives.

Evaluation of Microencapsulated Synbiotic Preparations Containing Lactobionic Acid

The aim of this paper was to assess the prebiotic properties of lactobionic acid in the human gastrointestinal model. Five different strains of probiotic, or potentially probiotic, bacteria were used in the microencapsulation process; these were Lactobacillus casei Shirota, Lactococcus lactis ATCC1, Lactobacillus fermentum, Bifidobacterium bifidum DSM 20456, and Bifidobacterium bifidum DSM 20082. Starch with a concentration of 4% (w/v) and a degree of substitution of 0.03 was used to produce the microcapsules. The alginian microcapsules we produced functioned as a protective barrier for the probiotic microorganisms closed in them, protecting them from adverse conditions in the human digestive tract. The microorganisms could thus survive the encapsulation process and the in vitro model digestion process while retaining the ability to produce biomass. Factors such as pH and time affect the solution of alginate microcapsules. The capsule solution began when a pH of 7.4 was reached; this corresponded to pH in the target probiotic site, an in vitro model of the colon. The capsules had completely dissolved after 24 h of digestion at a pH of 8. The addition of lactobionic acid stimulated the growth of probiotic and potentially probiotic bacteria, thus confirming its prebiotic properties.

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.

Survivability and controlled release of alginate-microencapsulated Pseudomonas fluorescens VUPF506 and their effects on biocontrol of Rhizoctonia solani on potato

Preserving the efficacy of plant probiotic bacteria in soil is a major challenge to the biological control of plant diseases. The microencapsulation technique is an important step in preserving the viability and activity of probiotics in adverse environmental conditions. The main objective of this study was to choose an appropriate coating for probiotic encapsulation. For this purpose, the survivability and controlled release of Pseudomonas fluorescens VUPF506 encapsulated with alginate (Alg) combined with whey protein concentrate (WPC), carboxymethyl cellulose (CMC), and peanut butter (PB) were evaluated. Moreover, the encapsulated cells were evaluated to control for Rhizoctonia solani in potato plants under in vivo conditions. The results showed that all tested wall material maintained more than 80% of the bacterial cells. The Alg-WPC microcapsules provided a better controlled release over two months. Interestingly, the greenhouse experiment also revealed that the treatment of potato plants with Alg-WPC microcapsules was the most effective treatment, suppressing 90% of the pathogen. The results showed that Alg-WPC is the most promising combination to improve the survivability of P. fluorescens VUPF506. Moreover, it can be used as a fertilizer due to its content of valuable amino acids.

Alginate Calcium Microbeads Containing Chitosan Nanoparticles for Controlled Insulin Release

Effective delivery system for oral insulin administration is a promising way for diabetes therapy. Herein, we prepared alginate microbeads containing chitosan nanoparticles (CNP) for controlled release of insulin. CNP was developed by reaction between tripolyphosphate (TPP) and chitosan. The ratio of TPP to chitosan was optimized aiming with smaller and more unified distributed CNP. TEM and DLS analysis confirmed that CNP has size around 150 nm with low PDI value and strong surface charge. Encapsulate ability for bovine serum albumin, working as model protein, was 11.45%, and the encapsulate efficiency was 23.70%. To modify the release profile of protein suitable for oral insulin delivery, sodium alginate was applied to coat on the surface of CNP by electrostatic interaction. After that, CaCl₂ was added to reinforce the alginate coating layer. FTIR analysis confirmed the interaction of alginate with chitosan and reaction with calcium ion. After reaction with Ca²⁺ ion, size measurement revealed that CNP was incorporated into alginate microbeads with mean diameter about 3.197 μm. Alginate microbeads presented irregular shape with small particles inside as revealed by optical microscope. Meanwhile, the release test demonstrated that protein release was pH-dependent. Acidic pH value retards protein release and neutral pH value promotes protein release. At last, insulin-loaded alginate microbeads were administrated to hyperglycemia model mice and blood glucose profile was monitored afterward. Insulin-loaded microbeads significantly lowered blood glucose level compared with mice treated with alginate microbeads without insulin. It is noted that insulin-loaded alginate microbeads could lower blood glucose level in much prolonged period of 96 h, indicating that insulin was released in controlled manner.

Probiotic and Antioxidant Potential of Lactobacillus reuteriLR12 and Lactobacillus lactisLL10 Isolated from Pineapple Puree and Quality Analysis of Pineapple-Flavored Goat Milk Yoghurt during Storage

In recent years, studies have focused on the therapeutic properties of probiotics to eliminate pathogenic microorganisms associated with various diseases. Lactobacilli are important probiotics groups that have been found to possess many health-promoting activities. This study was carried out to isolate LactobacillusreuteriLR12 and L. lactisLL10 from pineapple puree. The invitro analysis to evaluate probiotic characteristics of the isolated bacteria included survival in bile and acid tolerance. The cell-free supernatant of L. reuteri LR12 was effective against various pathogenic bacteria and fungi compared with L. lactisLL10. These two bacterial strains have strong anti-biofilm activity (100%) against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus. The bacterial strains exhibited adhesion properties to HT-29 cells (human colorectal adenocarcinoma). These bacteria showed DPPH- (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical scavenging activity, scavenging of hydroxyl radical activity, superoxide radical scavenging activity, and reducing power activity in the range of 72% ± 3%to 89.3% ± 1.7%, 64% ± 2.7%to 66.8% ± 1.5%, 59.8% ± 4.1% to 63.8% ± 2.1%, and 60.4% ± 1.8%to 66.1% ± 3.3%, respectively. Pineapple puree was used as the starter culture with milk for 2 days for yogurt preparation. Pineapple puree increased flavor and showed the physicochemical properties of yogurt. The finding of the sensory evaluation revealed no significant change compared with the control, except the appearance of yogurt. These findings show that Lactobacilli and pineapple puree have potential use in various probiotic preparations for the fermentation industry.

Potential effects of alginate-pectin biocomposite on the release of folic acid and their physicochemical characteristics

Potential effects of folates on the treatment of several human diseases like cognitive function, neural tube defects, coronary heart disease and certain kinds of cancers have been discovered. However, the stability of folic acid against adverse conditions is a great concern. The present study investigates various alginate (A)-pectin (P) gastrointestinal-resistant hydrogel to immobilize folic acid. This involves evaluating different compositions of alginate-pectin to achieve higher encapsulation efficiency and stability during simulated gastric (SG) and simulated intestinal (SI) conditions. Coated alginate hydrogels with pectin resulted significant (p < 0.05) better protection of folic acid compared to non-coated alginate hydrogel when exposed to SG condition and when exposed to SI condition, sustained release behavior obtained with the ratio of A70-P30. The structural and physicochemical properties of blended A-P hydrogel were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffractometer, indicating the presence of folic acid into the matrix and signified no covalent reaction between components. Therefore, this adequate composition of alginate-pectin showed to be a potential carrier for folic acid stability.

Survivability of alginate-microencapsulated Lactobacillus plantarum during storage, simulated food processing and gastrointestinal conditions

A comparison between the most investigated alginate-based encapsulating agents was performed in the current study. Here, the survivability of Lactobacillus plantarum microencapsulated with alginate (Alg) combined with skim milk (Sm), dextrin (Dex), denatured whey protein (DWP) or coated with chitosan (Ch) was evaluated after exposure to different heat treatments and in presence of some food additives, during storage and under simulated gastrointestinal condition. In addition, the encapsulated cells were evaluated for production of different bioactive compounds such as exopolysacchar. ides and antimicrobial substances compared with the unencapsulated cells. The results showed that only Alg-Sm maintained the viability of the cells >106 cfu/g at the pasteurization temperature (65 °C for 30 min). Interestingly, storage under refrigeration conditions increased the viability of L. plantarum entrapped within all the tested encapsulating agents for 4 weeks. However, under freezing condition, only Alg-DWP and Alg-Sm enhanced the survival of the entrapped cells for 3 months. All the microencapsulated cells were capable of growing at the different NaCl concentrations (1%-5%) except for cells encapsulated with Alg-Dex, showed viability loss at 3% and 5% NaCl concentrations. Tolerance of the microencapsulated cells toward organic acids was varied depending on the type of organic acid. Alg-Ch and Alg-Sm provide better survival for the cells under simulated gastric juice; however, all offer a good survival for the cells under simulated intestinal condition. Our findings indicated that Alg-Sm proved to be the most promising encapsulating combination that maintains the survivability of L. plantarum to the recommended dose level under almost all the stress conditions adopted in the current study. Interestingly, the results also revealed that microencapsulation does not affect the metabolic activity of the entrapped cells and there was no significant difference in production of bioactive compounds between the encapsulated and the unencapsulated cells.