Enhancing encapsulation efficiency of alginate capsules containing lactic acid bacteria by using different divalent cross-linkers sources

Entrapment of multi-scale structure of alginate beads stabilized with cellulose nanofibrils for potential intestinal delivery of lactic acid bacteria

Soybean cellulose nanofibrils (SCNFs) were formed by autoclave-enzymatic hydrolysis combined with ball milling. SCNFs were blended with sodium alginate (SA) to encapsulate lactic acid bacteria (LAB) through inotropic gelation. The effect of SCNFs on the multiscale structure of SA beads, leading to changes in the survival and release of LAB during simulated digestion, was investigated. Microscopy and rheological testing indicated that SCNF10-30 was well-dispersed in the SA paste in the form of interlaced nanofibrils, and could reduce the deformation of the paste under stress by 47.31 %. Multiscale structural analysis indicated SCNF10-30 not only increased the immobilized water of SA beads by 15.59 % by coordinating calcium, but also regulated the in situ-assembly of SA beads, including an increase in the scale of dimers from 6.73 nm to 8.32 nm and improved arrangement, thus forming a dense gel network. LAB viability of SA-SCNF10-30 in simulated digestion was increased by 1.3 log CFU/g compared to SA beads. Cellulose nanofibrils improved gastrointestinal survival and controlled release of LAB better than fiber rods. This study provides a strategy to regulate the multiscale structure of SA beads through nanofibrils to enable stabilization and sustainable release of LAB in gastrointestinal fluids.

Identification and evaluation of Escherichia coli strain ATCC 8739 as a surrogate for thermal inactivation of enterohemorrhagic Escherichia coli in fruit nectars: Impact of applied techniques on the decimal reduction time

The objective of this study was to identify a suitable surrogate for E. coli O157:H7 strain 19685/91 and O113:H21 strain TS18/08, by assessing their thermal resistance at temperatures of 60 °C, 65 °C, and 72 °C in strawberry nectar. The influence of the matrix and the research methodology on the decimal reduction time (D-value) was investigated. Thermal kinetics and safety assessment demonstrated that E. coli ATCC 8739 is a suitable surrogate. The study demonstrated that the presence of fruit particles in the nectar increased thermal resistance of the tested strains. Variations in D-values were observed depending on the research method employed, with D-values in glass capillaries were up to 6.6 times lower compared to larger sample volumes. Encapsulation of E. coli ATCC 8739 exhibited high efficiency of 90.25 ± 0.26% and maintained stable viable counts after 26 days of storage in strawberry nectar at 4 °C. There were no significant differences in thermal resistance between surrogates directly inoculated into strawberry nectar and those encapsulated in alginate beads. Additionally, the encapsulated strains did not migrate outside the beads. Therefore, encapsulated E. coli ATCC 8739 in alginate beads can be effectively utilized in industrial settings to validate thermal treatments as a reliable and safe method.

Microencapsulation of natural products using spray drying; an overview

AIMS

This study examines microencapsulation as a method to enhance the stability of natural compounds, which typically suffer from inherent instability under environmental conditions, aiming to extend their application in the pharmaceutical industry.

METHODS

We explore and compare various microencapsulation techniques, including spray drying, freeze drying, and coacervation, with a focus on spray drying due to its noted advantages.

RESULTS

The analysis reveals that microencapsulation, especially via spray drying, significantly improves natural compounds' stability, offering varied morphologies, sizes, and efficiencies in encapsulation. These advancements facilitate controlled release, taste modification, protection from degradation, and extended shelf life of pharmaceutical products.

CONCLUSION

Microencapsulation, particularly through spray drying, presents a viable solution to the instability of natural compounds, broadening their application in pharmaceuticals by enhancing protection and shelf life.

Application of biomacromolecules encapsulation systems for the long-term storage of Lactobacillus plantarum F1 and Lactobacillus reuteri 182

The aim of this study was to improve the viability of lactic acid bacteria (LAB) during extended storage of 1 year and mechanical characteristics of the calcium alginate beads with co-encapsulation of prebiotics and chitosan coating and subsequent freeze drying. The results revealed that the addition of trehalose to alginate matrix effectively protects the LAB cells during freeze drying, i.e., the survival rate has increased up to more than 92.5 %. Chitosan coating reinforced Ca-alginate beads, therefore the sphericity and mechanical strength of the beads improved. The findings also showed that bacteria encapsulation with the prebiotics resulted in more cells stability during the prolonged storage of 1 year and were 4.82 ± 0.06 log CFU g-1 in the lyophilized alginate-trehalose beads for Lactobacillus plantarum and 5.64 ± 0.08 log CFU g-1 in the lyophilized alginate-trehalose-inulin beads for Lactobacillus reuteri. No survival, however, was noted for the LAB cells in wet capsules after the same period. This study demonstrated that prebiotics had a significant impact on the viability of cells during freeze drying and storage. What is more, physical properties of the alginate beads were enhanced by coating beads with the chitosan.

Microcapsules and Nanoliposomes Based Strategies to Improve the Stability of Blueberry Anthocyanins

Blueberry anthocyanins are water-soluble natural pigments that can be used as both natural antioxidants and natural colorants. However, their structural instability greatly limits their application in the food, pharmaceutical, and cosmetic industries. In this study, blueberry anthocyanin microcapsules (BAM) and blueberry anthocyanin liposomes (BAL) were fabricated based on blueberry anthocyanins. Film dispersion methods were used to prepare the BAL. Their preparation processes were optimized and compared to improve the stability of the blueberry anthocyanins following exposure to light and high temperatures. The BAM were prepared through complex phase emulsification. The blueberry anthocyanins were protected by the shell materials composed of sodium alginate after being formed into BAM. Under the optimal conditions, the embedding rate of BAM and BAL can reach as high as 96.14% and 81.26%, respectively. In addition, the particle size, zeta potential, microtopography, and structure feature information of the BAM and BAL were compared. The average particle sizes of the BAM and BAL were 9.78 μm and 290.2 nm, respectively, measured using a laser particle size analyzer, and the zeta potentials of the BAM and BAL were 34.46 mV and 43.0 mV, respectively. In addition, the optimal preparation processes were determined through single-factor and response surface optimization experiments. The most important factors in the single-factor experiment for the preparation of microcapsules and liposomes were the content of CaCl2 and the amount of anthocyanin. The preservation rates in the light and dark were also compared, and the thermal stabilities of the BAM and BAL were characterized through differential thermal scanning. The results showed that both the BAM and BAL maintained the stability of blueberry anthocyanins, and no significant difference was found between the indices used to evaluate their stability. The results of this study provide theoretical support for the development of effective systems to maintain the stability of anthocyanins, thereby improving their bioavailability after ingestion by humans.

Development and characterization of rice bran-gum Arabic based encapsulated biofertilizer for enhanced shelf life and controlled bacterial release

Introduction

Currently, microbe-based approaches are being tested to address nutrient deficiencies and enhance nutrient use efficiency in crops. However, these bioinoculants have been unsuccessful at the commercial level due to differences in field and in-vivo conditions. Thus, to enhance bacterial stability, microbial formulations are considered, which will provide an appropriate microenvironment and protection to the bacteria ensuring better rhizospheric-colonization.

Methods

The present study aimed to develop a phosphobacterium-based encapsulated biofertilizer using the ion-chelation method, wherein a bacterial strain, Myroid gitamensis was mixed with a composite solution containing rice bran (RB), gum Arabic (GA), tricalcium phosphate, and alginate to develop low-cost and slow-release microbeads. The developed microbead was studied for encapsulation efficiency, shape, size, external morphology, shelf-life, soil release behavior, and biodegradability and characterized using SEM, FTIR, and XRD. Further, the wheat growth-promoting potential of microbeads was studied.

Results

The developed microbeads showed an encapsulation efficiency of 94.11%. The air-dried beads stored at 4°C were favorable for bacterial survival for upto 6 months. Microbeads showed 99.75% degradation within 110 days of incubation showing the bio-sustainable nature of the beads. The application of dried formulations to the pot-grown wheat seedlings resulted in a higher germination rate, shoot length, root length, fresh weight, dry weight of the seedlings, and higher potassium and phosphorus uptake in wheat.

Discussion

This study, for the first time, provides evidence that compared to liquid biofertilizers, the RB-GA encapsulated bacteria have better potential of enhancing wheat growth and can be foreseen as a future fertilizer option for wheat.

Sodium alginate based artificial biofilms polymerized by electrophoretic deposition for microbial hydrogen generation

This study developed an artificial biofilm of Rhodospirillum rubrum bacteria immobilized within an alginate matrix using electrophoretic deposition (EPD) on an electrode. The resulting biofilm immobilized bacteria effectively and maintained a high survival rate, facilitating stable and high-efficiency hydrogen generation for longer periods compared to biofilms produced using free bacteria. Hydrogen production efficiency remained constant when the substrate was periodically replaced, indicating that the bacteria could survive within the biofilm for long-term hydrogen production. EPD produced mechanically stable large-scale biofilms economically and rapidly, which effectively overcame operational limitations such as culture medium temperature, pH, and flow rate. Therefore, this proposed method has the potential to accelerate the commercialization of biohydrogen production systems through large-scale biofilm production to facilitate continuous hydrogen generation. The technique can be utilized in various hydrogel-based applications, providing a cost-effective and efficient manufacturing process with customized biological and mechanical properties. The developed biofilms have implications beyond biohydrogen production and could be applied to hydrogel-based medical, cosmetic, and food applications. This study highlights the importance of immobilizing bacteria for stable and efficient hydrogen generation and demonstrates the potential of EPD in fabricating mechanically stable biofilms for large-scale production.

Dry alginate beads for fecal microbiota transplantation: from model strains to fecal samples

Clostridioides difficile infection (CDI) is a critical nosocomial infection with more than 124,000 cases per year in Europe and a mortality rate of 15-17%. The standard of care (SoC) is antibiotic treatment. Unfortunately, the relapse rate is high (∼35%) and SoC is significantly less effective against recurrent infection (rCDI). Fecal microbiota transplantation (FMT) is a recommended treatment against rCDI from the second recurrence episode and has an efficacy of 90%. The formulation of diluted donor stool deserves innovation because its actual administration routes deserve optimization (naso-duodenal/jejunal tubes, colonoscopy, enema or several voluminous oral capsules). Encapsulation of model bacteria strains in gel beads were first investigated. Then, the encapsulation method was applied to diluted stools. Robust spherical gel beads were obtained. The mean particle size was around 2 mm. A high loading of viable microorganisms was obtained for model strains and fecal samples. For plate-counting, values ranged from 10¹⁵ to 10¹⁷ CFU/g for single and mixed model strains, and 10⁶ to 10⁸ CFU/g for fecal samples. This corresponded to a viability of 30% to 60% as assessed by flow cytometry. This novel formulation is promising as the technology is applicable to both model strains and bacteria contained in the gut microbiota.

Development of Zn biofertilizer microbeads encapsulating Enterobacter ludwigii-PS10 mediated alginate, starch, poultry waste and its efficacy in Solanum lycopersicum growth enhancement

In the present farming era, rhizobacteria as beneficial biofertilizers can decrease the negative effects of Zinc (Zn) agrochemicals. However, their commercial viability and utility are constrained by their instability under field conditions. Thus, to enhance their stability, microbial formulations are considered, which will not only offer an appropriate microenvironment, and protection but also ensure a high rate of rhizospheric-colonization. The goal of this study was to create a new formulation for the Zn-solubilizing bacteria E. ludwigii-PS10. The studied formulation was prepared using the extrusion technique, wherein a composite solution containing alginate, starch, zinc oxide, and poultry waste was uniformly mixed with the bacterial strain PS10 to develop low-cost, eco-friendly, and slow-release microbeads. The produced microbead was spherical, and characterized by SEM, FTIR, and XRD. Further, the microbeads were analyzed for their survival stability over 3 months of storage at room temperature and 4 °C. The effect of the microbead on the vegetative growth of tomato plants was investigated. Results showed that 94 % of the encapsulated microbial beads (EMB) matrix was able to encapsulate the bacterial strain PS10. The dried EMB demonstrated a moisture content of 2.87 % and was able to preserve E. ludwigii-PS10 survival at room temperature at the rate of 85.6 %. The application of the microbead to the tomato plants significantly increased plant biomass and Zn content. As a result, our findings support the use of this novel EMB prepared using an alginate/poultry waste/starch mixture to increase bacterial cell viability and plant growth.

Co-encapsulation of Lactobacillus plantarum and bioactive compounds extracted from red beet stem (Beta vulgaris L.) by spray dryer

Probiotic bacteria and bioactive compounds obtained from plant origin stand out as ingredients with the potential to increase the healthiness of functional foods, as there is currently a recurrent search for them. Probiotics and bioactive compounds are sensitive to intrinsic and extrinsic factors in the processing and packaging of the finished product. In this sense, the present study aims to evaluate the co-encapsulation by spray dryer (inlet air temperature 120 °C, air flow 40 L / min, pressure of 0.6 MPa and 1.5 mm nozzle diameter) of probiotic bacteria (L.plantarum) and compounds extracted from red beet stems (betalains) in order to verify the interaction between both and achieve better viability and resistance of the encapsulated material. When studying the co-encapsulation of L.plantarum and betalains extracted from beet stems, an unexpected influence was observed with a decrease in probiotic viability in the highest concentration of extract (100 %), on the other hand, the concentration of 50 % was the best enabled and maintained the survival of L.plantarum in conditions of 25 °C (63.06 %), 8 °C (88.80 %) and -18 °C (89.28 %). The viability of the betalains and the probiotic was better preserved in storage at 8 and -18 °C, where the encapsulated stability for 120 days was successfully achieved. Thus, the polyfunctional formulation developed in this study proved to be promising, as it expands the possibilities of application and development of new foods.

Assessment of Ultrasonic Stress on Survival and β-Glucosidase Activity of Encapsulated Lactiplantibacillus plantarum BCRC 10357 in Fermentation of Black Soymilk

The enhanced β-glucosidase activity of encapsulated Lactiplantibacillus plantarum BCRC 10357 within calcium alginate capsules was investigated by ultrasonic stimulation to induce the stress response of the bacteria for the biotransformation of isoflavones in black soymilk. The effects of various ultrasound durations, sodium alginate concentrations (% ALG), and cell suspensions on the β-glucosidase activity of encapsulated bacteria were explored. The β-glucosidase activity of encapsulated L. plantarum BCRC 10357 with ultrasonic stimulation (40 kHz/300 W) was greater than that without ultrasound. With 20 min of ultrasonic treatment, the β-glucosidase activity of encapsulated L. plantarum BCRC 10357 from 2% ALG/0.85% NaCl cell suspension was 11.47 U/mL at 12 h, then increased to 27.43 U/mL at 36 h and to 26.25 U/mL at 48 h in black soymilk at 37 °C, showing the high adaptation of encapsulated L. plantarum BCRC 10357 encountering ultrasonic stress to release high β-glucosidase until 48 h, at which point the ratio of isoflavone aglycones (daidzein and genistein) in total isoflavones (daidzin, genistin, daidzein, and genistein) was 98.65%, reflecting the effective biotransformation of isoflavone glycosides into aglycones by β-glucosidase. In this study, the survivability and β-glucosidase activity of encapsulated L. plantarum BCRC 10357 were enhanced under ultrasonic stimulation, and were favorably used in the fermentation of black soymilk.

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.

Camel milk-derived probiotic strains encapsulated in camel casein and gelatin complex microcapsules: Stability against thermal challenge and simulated gastrointestinal digestion conditions

Probiotics have received increased attention due to their nutritional and health-promoting benefits. However, their viability is often impeded during food processing as well as during their gastrointestinal transit before reaching the colon. In this study, probiotic strains Lactobacillus rhamnosus MF00960, Pediococcus pentosaceus MF000967, and Lactobacillus paracasei DSM20258 were encapsulated within sodium alginate, camel casein (CC), camel skin gelatin (CSG) and CC:CSG (1:1 wt/wt) wall materials. All 3 strains in encapsulated form showed an enhanced survival rate upon simulated gastrointestinal digestion compared with free cells. Among the encapsulating matrices, probiotics embedded in CC showed higher viability and is attributed to less porous structure of CC that provided more protection to entrapped probiotics cells. Similarly, thermal tolerance at 50°C and 70°C of all 3 probiotic strains were significantly higher upon encapsulation in CC and CC:CSG. Scanning electron microscope micrographs showed probiotic strains embedded in the dense protein matrix of CC and CSG. Fourier-transform infrared spectroscopy showed that CC- and CSG-encapsulated probiotic strains exhibited the amide bands with varying intensity with no significant change in the structural conformation. Probiotic strains encapsulated in CC and CC:CSG showed higher retention of inhibitory properties against α-glucosidase, α-amylase, dipeptidyl peptidase-IV, pancreatic lipase, and cholesteryl esterase compared with free cells upon exposure to simulated gastrointestinal digestion conditions. Therefore, CC alone or in combination with CSG as wall materials provided effective protection to cells, retained their bioactive properties, which was comparable to sodium alginate as wall materials. Thus, CC and CC:CSG can be an efficient wall material for encapsulation of probiotics for food applications.

W/O/W double emulsion-loaded alginate capsules containing Lactobacillus plantarum and lipophilic sea buckthorn (Hippophae rhamnoides L.) pomace extract in different phases

In this study, double emulsion containing L. plantarum F1 cells and prebiotic mannitol in the inner water phase, lipophilic sea buckthorn pomace extract as an antioxidant in the oil phase, and alginate in the outer water phase showed high encapsulation yield (82.19%), good cell survival rate (76.99%) and low chemical degradation of the oil (peroxide value - 3.8 meq O₂/kg fat) after 42 days of storage. Gelation of the outer water phase enhanced the viability of L. plantarum F1 cells both during storage and under gastrointestinal conditions due to strong physical barrier formation. Encapsulated L. plantarum F1 viability throughout the 30-day storage period decreased to the value meeting the minimum required dose for probiotics. In vitro digestion of the loaded alginate capsules showed high survival rate of encapsulated cells under gastric conditions and significant reduction at the end of the duodenal phase of digestion.

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.

Purification of Crude Fructo-Oligosaccharide Preparations Using Probiotic Bacteria for the Selective Fermentation of Monosaccharide Byproducts

Probiotics are microbes that promote health when consumed in sufficient amounts. They are present in many fermented foods or can be provided directly as supplements. Probiotics utilize non-digestible prebiotic oligosaccharides for growth in the intestinal tract, contributing to a healthy microbiome. The oligosaccharides favored by probiotics are species-dependent, as shown by the selective utilization of substrates in mixed sugar solutions such as crude fructo-oligosaccharides (FOS). Enzymatically produced crude FOS preparations contain abundant monosaccharide byproducts, residual sucrose, and FOS varying in chain length. Here we investigated the metabolic profiles of four probiotic bacteria during the batch fermentation of crude FOS under controlled conditions. We found that Bacillus subtilis rapidly utilized most of the monosaccharides but little sucrose or FOS. We therefore tested the feasibility of a microbial fed-batch fermentation process for the purification of FOS from crude preparations, which increased the purity of FOS from 59.2 to 82.5% with a final concentration of 140 g·l-1. We also tested cell immobilization in alginate beads as a means to remove monosaccharides from crude FOS. This encapsulation concept establishes the basis for new synbiotic formulations that combine probiotic microbes and prebiotic oligosaccharides.

Deep insights into urinary tract infections and effective natural remedies

Background

Urinary tract infection (UTI) is a common occurrence in females, during pregnancy, and in peri- and postmenopausal women. UTIs are associated with significant morbidity and mortality, and they affect the quality of life of the affected patients. Antibiotic therapy is an effective approach and reduces the duration of symptoms. Development of resistance, adverse effects of antibiotics, and other associated problems lead to establishing the research framework to find out the alternative approaches in controlling UTIs. Natural approaches have been extensively used for the management of various diseases to improve symptoms and also improve general health.

Main body

Different databases were employed to identify studies reporting on natural options including herbal medicines, vitamins, trace elementals, sugars, and probiotics without time limitations.

Conclusion

Herbal medicines can be effective at the first sign of the infection and also for short-term prophylaxis. Using vitamins, trace elementals, and/or sugars is an effective approach in preventing UTIs, and a combination of them with other antibacterial agents shows positive results. Probiotics have great potential for the threat of antibiotic over-usage and the prevalence of antibiotic-resistant microorganisms. This study may be of use in developing the efficient formulation of treatment of UTI.

Effective passivation of lead by phosphate solubilizing bacteria capsules containing tricalcium phosphate

Phosphate solubilizing bacteria (PSBs) shows high potential to be used for lead passivation in sediments due to the abilities of releasing phosphate and the subsequent formation of insoluble Pb-phosphate compounds. In this research, microbial capsules implemented with sodium alginate and CaCl₂, containing Leclercia adecarboxylata L15 (a lead resistant PSB) and Ca₃(PO₄)₂, were developed and the performance on lead passivation under different conditions was examined. The optimal concentrations of sodium alginate and CaCl₂ for formulating the capsules were determined to be 0.3% and 10%, respectively. The removal efficiency of Pb²⁺ by capsules containing L15 and Ca₃(PO₄)₂ was up to 98% with a capsule dosage of 2%, initial Pb²⁺ concentration of 1mM and pH of 3.0, which was better than that of free L15 (18%) and capsules containing only L15 (34%). Lead was immobilized via the formation of Pb₅(PO₄)₃Cl on the surface and Pb₃(PO₄)₂ in the interior of the capsules. The simulated sediment remediation experiments showed that the acid soluble fraction of lead reduced from 28% to 14% and transformed into more stable fractions after 10 days. The experiment results indicated that PSBs capsules coupled with phosphate materials have a great promise for application in remediation of lead contaminated sediments.

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.