Textural properties of alginate–pectin beads and survivability of entrapped Lb. casei in simulated gastrointestinal conditions and in yoghurt

Mixed κ/ι-carrageenan - LM pectin gels: Relating the rheological and mechanical properties with the capacity for probiotic encapsulation

The rheological and mechanical properties of mixed κ/ι-carrageenan - LM pectin gels were determined, and the potential of these gels for the formation of beads using the extrusion method and for the encapsulation of Lacticaseibacillus rhamnosus ATCC 53103 (LGG) was evaluated. Self-standing gels were obtained with all formulations evaluated. Carrageenan-rich gels, with carrageenan fraction (XC) ≥ 0.75, exhibited the highest storage modulus, but they were also brittle, while pectin-rich gels (XC ≤ 0.25) presented the highest hardness and cohesiveness. Pectin-rich formulations formed beads with the smallest initial diameter (2.40-2.45 mm), and the addition of carrageenan produced significantly more spherical beads compared to pure-pectin ones. As pectin-rich beads were the formulations that resisted simulated gastrointestinal conditions, these were selected for the encapsulation of LGG. These beads showed high encapsulation yields (87-96 %), and the percentage reduction of CFU/g during storage and simulated gastrointestinal conditions was not significantly different among formulations, the latter being significantly lower for encapsulated cells (8.64-15.03 %) compared to free cells (71.20 %). These results indicate that carrageenan-pectin gel beads with XC ≤ 0.25 were successful in encapsulating probiotic bacteria, and this capacity was related to the rheological and mechanical properties of the gels.

Delivery of Probiotic-Loaded Microcapsules in the Gastrointestinal Tract: A Review

Probiotics are live microorganisms that inhabit the gastrointestinal tract and confer health benefits to consumers. However, a sufficient number of viable probiotic cells must be delivered to the specific site of interest in the gastrointestinal tract to exert these benefits. Enhanced viability and tolerance to sublethal gastrointestinal stress can be achieved using appropriate coating materials and food matrices for orally consumed probiotics. The release mechanism and interaction of probiotic microcapsules with the gastrointestinal tract have been minimally explored in the literature to date. To the authors' knowledge, no review has been published to discuss the nature of release and the challenges in the targeted delivery of probiotics. This review addresses gastrointestinal-related complications in the formulation of targeted delivery and controlled release of probiotic strains. It investigates the impacts of environmental stresses during the transition stage and delivery to the target region in the gastrointestinal tract. The influence of factors such as pH levels, enzymatic degradation, and redox conditions on the release mechanisms of probiotics is presented. Finally, the available methods to evaluate the efficiency of a probiotic delivery system, including in vitro and in vivo, are reviewed and assessed. The paper concludes with a discussion highlighting the emerging technologies in the field and emphasising key areas in need of future study.

Exploring the Potential of Endophytic Microorganisms and Nanoparticles for Enhanced Water Remediation

Endophytic microorganisms contribute significantly to water bioremediation by enhancing pollutant degradation and supporting aquatic plant health and resilience by releasing bioactive compounds and enzymes. These microorganisms inhabit plant tissues without causing disease or any noticeable symptoms. Endophytes effectively aid in eliminating contaminants from water systems. Nanoparticles serve as potent enhancers in bioremediation processes, augmenting the efficiency of pollutant degradation by increasing surface area and bioavailability, thereby improving the efficacy and rate of remediation. Their controlled nutrient release and ability to stabilize endophytic colonization further contribute to the enhanced and sustainable elimination of contaminated environments. The synergistic effect of endophytes and nanoparticles in water remediation has been widely explored in recent studies, revealing compelling outcomes. Water pollution poses significant threats to human health, ecosystems, and economies; hence, the sixth global goal of the Sustainable Development Agenda 2030 of the United Nations aims to ensure the availability and sustainable management of water resources, recognizing their crucial importance for current and future generations. Conventional methods for addressing water pollution exhibit several limitations, including high costs, energy-intensive processes, the production of hazardous by-products, and insufficient effectiveness in mitigating emerging pollutants such as pharmaceuticals and microplastics. Noticeably, there is an inability to effectively remove various types of pollutants, thus resulting in incomplete purification cycles. Nanoparticle-enhanced water bioremediation offers an innovative, eco-friendly alternative for degrading contaminants. A growing body of research has shown that integrating endophytic microorganisms with nanoparticles for water bioremediation is a potent and viable alternative. This review examines the potential of using endophytic microorganisms and nanoparticles to enhance water remediation, exploring their combined effects and applications in water purification. The paper also provides an overview of synthetic methods for producing endophyte-nanoparticle composites to optimize their remediation capabilities in aqueous environments. The final section of the review highlights the constraints related to integrating endophytes with nanoparticles.

Improving the survival of Lactobacillus plantarum FZU3013 by phase separated caseinate/alginate gel beads

The phase separation behavior of mixed solution of caseinate (Cas) and alginate (Alg) was investigated. Lactobacillus plantarum FZU3013 was encapsulated using 4 % Cas/1 % Alg gel beads with a phase-separated structure. The bacteria were predominantly distributed in the Alg-rich continuous phase. The use of 4 % Cas/1 % Alg beads resulted in higher encapsulation efficiency for L. plantarum FZU3013 compared to 1 % Alg beads. After 5 weeks of storage at 4 °C, the viable count in 4 % Cas/1 % Alg beads was 8.3 log CFU/g, which was 1.1 log CFU/g higher than that of the 1 % Alg beads. When 1 % Alg beads of the smallest size were subjected to in vitro digestion, no viable bacteria could be detected at the end of the digestion, whereas the 4 % Cas/1 % Alg beads of the smallest size had a viable count of 3.9 log CFU/g. When the size of the 4 % Cas/1 % Alg beads was increased to 1000 μm, the viable count was 7.0 log CFU/g after digestion. The results of infrared spectroscopy and zeta potential indicated that hydrogen bonding and electrostatic interactions between caseinate and alginate reinforced the structure of the gel beads and improved the protection for L. plantarum FZU 3013.

In Vitro and In Vivo Characterisation of Lactiplantibacillus plantarum LAB12 in Pea Protein-Alginate Microcapsules

The susceptibility of probiotics to high temperature and low pH remains a major challenge in food industries. Numerous commercially available probiotic products were reportedly presented with lower probiotic viability than claimed. To confer health benefits to the host, it is essential that probiotic strain remains viable at optimal amount during food processing procedures, storage and passage through the gastrointestinal tract. This study addressed these issues by immobilising Lactiplantibacillus plantarum LAB12 isolated from tempeh (fermented soybean) in a polymeric matrix made up of alginate (Alg, 0.5% w/v) and denatured pea protein isolate (PPi, 1-10% w/v) using the emulsion/acidification technique. Alg supplemented with 10% PPi (Alg-PPi10) appeared to be optimally small (< 350 µm), substantiated by the improved surface smoothness and uniform dispersion of probiotics in the Alg-PPi core. The findings indicated that microencapsulation enhanced thermal stability of L. plantarum LAB12. The microencapsulated L. plantarum LAB12 remained highly viable (80%) despite exposure to 100 °C for 5 min. The microencapsulated cell number during storage at 4 and 25 °C for 8 weeks was greater than 7 log CFU g-1. L. plantarum LAB12 encapsulated in Alg-PPi10 exhibited high viability (96%) in simulated gastric juice (at pH 1.8 for 120 min) and facilitated maximum release of probiotics (> 9 log CFU g-1) in simulated intestinal fluid (at pH 6.8 for 240 min). Whilst retaining their intrinsic cholesterol lowering effect, microencapsulation conferred additional advantages to L. plantarum LAB12 in terms of lowering serum triglyceride and increasing HDL cholesterol in zebrafish fed with high-cholesterol diet (HCD). Overall, our findings strongly imply the potential use of Alg-PPi10 as an effective medium that confers thermal protection and facilitates pH-sensitive release of cholesterol-reducing L. plantarum LAB12. This will allow the diverse applications L. plantarum LAB12 across health, food and agro-feed industries amongst others.

Modification of pectin/starch-based beads with additives to improve Bacillus subtilis encapsulation for agricultural applications

The use of Bacillus as biofertilizer is a sustainable strategy to increase agricultural productivity, but it still requires the development of formulations to protect cells from stressful conditions. Ionotropic gelation using a pectin/starch matrix is a promising encapsulation strategy to achieve this goal. By incorporating additives such as montmorillonite (MMT), attapulgite (ATP), polyethylene glycol (PEG), and carboxymethyl cellulose (CMC), the properties of these encapsulated products could be further improved. In this study, we investigated the influence of these additives on the properties of pectin/starch-based beads for the encapsulation of Bacillus subtilis. FTIR analysis indicated pectin and Ca2+ ions interactions, while the XRD showed good dispersion of clays in the materials. SEM and X-ray microtomography revealed differences in the morphology of the beads due to the use of the additives. The viabilities at the encapsulation were higher than 1010 CFU g-1 for all formulations, with differences in the release profiles. In terms of cell protection, the pectin/starch, pectin/starch-MMT and pectin/starch-CMC formulations showed the highest cell viability after exposure to fungicide, while the pectin/starch-ATP beads showed the best performance after UV exposure. Moreover, all formulations maintained more than 109 CFU g-1 after six months of storage, which meets values required for microbial inoculants.

Improved Loading Capacity and Viability of Probiotics Encapsulated in Alginate Hydrogel Beads by In Situ Cultivation Method

The objective of this research was to encapsulate probiotics by alginate hydrogel beads based on an in situ cultivation method and investigate the influences on the cell loading capacity, surface and internal structure of hydrogel beads and in vitro gastrointestinal digestion property of cells. Hydrogel beads were prepared by extrusion and cultured in MRS broth to allow probiotics to grow inside. Up to 10.34 ± 0.02 Log CFU/g of viable cell concentration was obtained after 24 h of in situ cultivation, which broke through the bottleneck of low viable cell counts in the traditional extrusion method. Morphology and rheological analyses showed that the structure of the eventually formed probiotic hydrogel beads can be loosed by the existence of hydrogen bond interaction with water molecules and the internal growth of probiotic microcolonies, while it can be tightened by the acids metabolized by the probiotic bacteria during cultivation. In vitro gastrointestinal digestion analysis showed that great improvement with only 1.09 Log CFU/g of loss in viable cells was found after the entire 6 h of digestion. In conclusion, the current study demonstrated that probiotic microcapsules fabricated by in situ cultivation method have the advantages of both high loading capacity of encapsulated viable cells and good protection during gastrointestinal digestion.

Self-demise of soft rot bacteria by activation of microbial predators by pectin-based carriers

Soft rot pectobacteria (SRP) are phytopathogens of the genera Pectobacterium and Dickeya that cause soft rots on a wide range of crops and ornamental plants. SRP produce plant cell wall degrading enzymes (PCWDEs), including pectinases. Bdellovibrio and like organisms are bacterial predators that can prey on a variety of Gram-negative species, including SRP. In this research, a low methoxyl pectin (LMP)-based immobilization system for B. bacteriovorus is established. It takes advantage that pectin residues induce PCWDE secretion by the pathogens, bringing upon the release of the encapsulated predators. Three commercial LMPs differing in the degree of esterification (DE) and amidation (DA) were tested as potential carriers, by examining their effect on SRP growth, enzymes secretion and substrate breakdown. A clear advantage was observed for pectin 5 CS with the lowest DE and DA content. The degradation of 5 CS pectin-based carriers was further optimized by reducing cross-linker and pectin concentration, by adding gelatin and by dehydration. This resulted in SRP-induced disintegration of the carrier within 72 h. The released encapsulated predator caused a large decrease in SRP population while its own significantly increased, demonstrating the efficiency of this system in which the pathogen brings about its own demise.

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

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

Microencapsulation of Bacillus Strains for Improving Wheat (Triticum turgidum Subsp. durum) Growth and Development

Bio-formulation technologies have a limited impact on agricultural productivity in developing countries, especially those based on plant growth-promoting rhizobacteria. Thus, calcium alginate microbeads were synthesized and used for the protection and delivery of three beneficial Bacillus strains for agricultural applications. The process of encapsulation had a high yield per gram for all bacteria and the microbeads protected the Bacillus strains, allowing their survival, after 12 months of storage at room temperature. Microbead analysis was carried out by observing the rate of swelling and biodegradation of the beads and the released-establishment of bacteria in the soil. These results showed that there is an increase of around 75% in bead swelling on average, which allows for larger pores, and the effective release and subsequent establishment of the bacteria in the soil. Biodegradation of microbeads in the soil was gradual: in the first week, they increased their weight (75%), which consistently results in the swelling ratio. The co-inoculation of the encapsulated strain TRQ8 with the other two encapsulated strains showed plant growth promotion. TRQ8 + TRQ65 and TRQ8 + TE3^T bacteria showed increases in different biometric parameters of wheat plants, such as stem height, root length, dry weight, and chlorophyll content. Thus, here we demonstrated that the application of alginate microbeads containing the studied strains showed a positive effect on wheat plants.

Development of alginate/pectin microcapsules by a dual process combining emulsification and ultrasonic gelation for encapsulation and controlled release of anthocyanins from grapes (Vitis labrusca L.)

The aim of this study was to investigate the physicochemical, morphological, and gastrointestinal release properties of an anthocyanin-rich extract of grapes in alginate and pectin beads as carriers; the effects of ultrasonic gelation combined with emulsification were also investigated. In general, the alginate beads showed smaller size and more regular shape compared to pectin. The effect of emulsification combined with ionic gelation was more pronounced in the alginate beads and resulted in higher retention of anthocyanins, higher antioxidant capacity, and also allowed the best release profile during intestinal digestion. Thus, the simultaneous strategy could be an interesting delivery system and enhance the release of anthocyanins, providing an opportunity for the development of ingredients with different bioactive properties.

Administration of microencapsulated Enterococcus faecium ABRIINW.N7 with fructo-oligosaccharides and fenugreek on the mortality of tilapia challenged with Streptococcus agalactiae

We investigated the probiotic potential of a microencapsulated Enterococcus faecium ABRIINW.N7 for control of Streptococcus agalactiae infection in hybrid (Oreochromis niloticus × Oreochromis mossambicus) red tilapia. A two-phase experiment approach was completed in which E. faecium bacteria were propagated, from which a culture was isolated, identified using molecular techniques, and microencapsulated to produce a stable commercial fructooligosaccharide (FOS) and fenugreek (Fk) product of optimal concentration. The FOS and Fk products were assessed in a 90-days in vivo challenge study, in which red hybrid tilapia were allocated to one of five treatments: (1) No Streptococcus agalactiae (Sa) challenge (CON); (2) Sa challenge only (CON+); (3) Sa challenge in a free cell (Free Cell); (4) Sa challenge with 0.8% (w/v) Alginate; (5) Microencapsulated FOS and Fk. In vitro results showed high encapsulation efficiency (≥98.6 ± 0.7%) and acceptable viability of probiotic bacteria within the simulated fish digestive system and high stability of viable cells in all gel formulations (34 < SR% <63). In vivo challenges demonstrated that the FOS and Fk products could be used to control S. agalactiae infection in tilapia fish and represented a novel investigation using microencapsulation E. faecium as a probiotic diet for tilapia fish to control S. agalactiae infection and to lower fish mortality. It is recommended that local herbal gums such as 0.2% Persian gum and 0.4% Fk in combination with 0.8% alginate (Formulation 7) can be used as a suitable scaffold and an ideal matrix for the encapsulation of probiotics. These herbal gums as prebiotics are capable of promoting the growth of probiotic cells in the food environment and digestive tract.

The Effect of Pectin Branching on the Textural and Swelling Properties of Gel Beads Obtained during Continuous External Gelation Process

The aim of the study was to produce gel beads under continuous conditions. Pectins obtained from black and red currants and commercial apple pectin were used as the material. For the production of gel beads, a self-designed device was used. The designed device allows for the production of gel beads in a continuous process, the properties of which are similar to those obtained in the classic, batch process. Thanks to the device, it is possible to obtain a repeatable product while reducing the workload. The produced gel beads were tested for water absorption and textural properties. The water absorption of the obtained gel capsules is strongly influenced by the pectin chain structure. Pectin beads obtained from currant pectins have a less hard structure and are more sensitive to deformation than those from apple pectin. Shorter and more branched chains of currant pectin than apple pectin form gels with a delicate structure, which strongly absorbs water, and unlike apple pectin gel, it disintegrates. The results show that the use of raw material obtained from different sources allows for obtaining products with various properties, using the same method; moreover, the used device is fully scalable and can be used in large scale.

Electrosprayed chitosan-coated alginate-pectin beads as potential system for colon-targeted delivery of ellagic acid

BACKGROUND

Ellagic acid (EA), a potent dietary antioxidant, has limited bioavailability owing to its rapid absorption in the stomach and small intestine, and EA is transformed to more bioavailable compounds - urolithins - in the colon. An encapsulation system that sustains the release of EA in the gastrointestinal system and delivers more EA into the colon could improve the oral bioavailability of EA. Electrosprayed EA-loaded alginate-pectin beads were produced and coated with low- (LC) and high-molecular-weight chitosan (HC). The EA release from uncoated and coated beads under simulated gastrointestinal conditions was evaluated. The samples were characterized by particle size, gel strength, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analysis.

RESULTS

The encapsulation efficiency (EE%) of EA ranged from 49.53% to 69.85% for uncoated beads, which was elevated up to 86.50% by coating, and LC coating provided higher EE%. Pectin addition to alginate and chitosan coating reduced the gel strength and changed the size depending on the molecular weight of chitosan. SEM images of pectin-added beads showed fewer cracks but more wrinkles, and chitosan coating presented more aggregated surfaces. The ionic interaction of alginate-pectin-chitosan and the entrapment of EA were confirmed by FTIR. In the gastric medium, EA release was very low from uncoated beads (15.2-19.8%), and totally restricted by chitosan coating. In the intestinal stage, EA release from LC-coated alginate-pectin beads was only 18%, and it was between 55% and 65% for uncoated or HC-coated counterparts.

CONCLUSION

The LC-coated alginate-pectin beads could be further explored as a potential system for colon-targeted delivery of EA. © 2021 Society of Chemical Industry.

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

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

Physicochemical and release behaviour of phytochemical compounds based on black jamun pulp extracts-filled alginate hydrogel beads through vibration dripping extrusion

The phytochemical-rich extract obtained from black jamun pulp were encapsulated using vibrating dripping extrusion technique. The utilisation of alginate (AL) with four variations of core-shell material comprising gum Arabic (AL-GA), guar gum (AL-GG), pectin (AL-P) and xanthan gum (AL-X) was engaged to form calcium-alginate based lyophilised jamun extract encapsulated beads. It resulted that among four variations, lyophilised alginate with AL-GG based encapsulated jamun extract filled beads have better physicochemical characteristics and 95% encapsulation efficiency. The results revealed the morphological comparison of each variation. The release behaviour of AL-GG based beads has a higher release of total phenolics (TPC) and total anthocyanin content (TAC). The release kinetics model involving Ritger-Peppas and Higuchi model were applied for release TPC and TAC of all variations of beads. The Ritger-Peppas model was found best suitable in terms of average R² (0.965) and lowest χ² (0.0039). The release kinetics study showed that AL-GA based beads followed by AL-GG could also be the best suitable in release behaviour using simulated gastrointestinal fluids at 140-160 min. Overall, results shown the encapsulated Jamun beads have the best agro-industrial efficacy in form of phytochemical compounds based microparticles, holding decent antioxidant potential.

In vitro digestion of sodium alginate/pectin co-encapsulated Lactobacillus bulgaricus and its application in yogurt bilayer beads

The purpose of this study was to prepare sodium alginate (SA)/pectin (PE) hydrogel microspheres using the extrusion method to encapsulate Lactobacillus bulgaricus. Microscopic observation showed that the beads were spherical with a smooth and uniform surface. For microspheres with a diameter range of 140-156 μm, the encapsulation efficiency reached 85.67%. After simulating saliva, gastric juice, and intestinal juice, the activity of the microcapsules was estimated to be 5.78 × 10⁴ log colony forming unit (CFU)/mL. These data show that the use of SA and PE encapsulated probiotics exhibit enhanced viability. In addition, double-layer beads containing probiotic microspheres and yogurt were prepared, and physical and chemical analysis was performed using scanning electron microscopy, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. Texture and sensory property analysis revealed that the beads had good elasticity, chewiness, and high commercial value. Collectively, these findings indicate that SA and PE can be used for the encapsulation, protection, and gastrointestinal delivery of probiotics. Moreover, these microcapsules exhibit good stability in vitro and improve yogurt characteristics by increasing the survival rate of encapsulated probiotics, thus demonstrating their commercial application potential.

Microencapsulation of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis BB-12 in pectin and sodium alginate: A comparative study on viability, stability, and structure

The present study aimed at examining whether the microencapsulation of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis BB-12 inside hydrogels could prolong their survival in freeze-drying conditions, stored at 4℃ and in the gastrointestinal medium. Microencapsulation was performed by emulsion with a syringe, while sodium alginate and high methoxyl pectin were used as a carrier material. A relatively high efficiency of encapsulation was obtained (>92%). Z-Average and pdI in samples were not significant (p < .05). In different treatments, changes in the number of bacteria after freeze-drying, 30 days of storage, and gastrointestinal conditions, compared to each other, were significant (p < .05). However, the survival rate after a reduction during storage was higher than 106 cfu/g, indicating the suitability of the microencapsulation process. The surface of microcapsules observed by a scanning electron microscope (SEM) confirmed the success of encapsulation. Finally, a lower decrease in the count of microencapsulated was observed in comparison to the free cells.

Enriching alginate matrix used for probiotic encapsulation with whey protein concentrate or its trypsin-derived hydrolysate: Impact on antioxidant capacity and stability of fermented whey-based beverages

The present research is part of an effort to create whey-based functional food. Previously, it was concluded that proteins and peptides in an encapsulation matrix contribute to mechanical properties of beads, fermentative activity, acid and bile tolerance, and the survival of probiotics during the simulated gastrointestinal condition. This research evaluates the effects of using whey protein concentrate and trypsin hydrolysate as components of a matrix for probiotic encapsulation on the antioxidant capacity of a beverage. Carrier with hydrolysate showed better encapsulation efficiency, spherical factor, and antioxidant capacity before and after fermentation compared to the carrier with non-hydrolyzed proteins. Hydrolysis of protein used for carrier formulation positively impacts the beverage's antioxidant properties and probiotic viability during 28 days of storage. Using proteins, especially peptides, as a matrix component achieved three objectives: protection of probiotics, enrichment of products with antioxidants, and neutralization of possible bitter taste (because the bitter tasting peptides are incorporated into the matrix and as such cannot contribute to the taste of the product) that bioactive peptides usually possess.

Fabrication of fish gelatin / sodium alginate double network gels for encapsulation of probiotics

BACKGROUND

To improve the environmental resistance of probiotics, and particularly their survival in the gastrointestinal environment, a fish gelatin (FG) / sodium alginate (SA) double network gelation (FSDN) was developed to encapsulate them. Thermal treatment and calcium ion inducement were adopted to fabricate fish gelatin and sodium alginate gels. It was feasible to scale up this process. The effects of FG concentration (0-60 g/L) on FSDN properties, including morphology, water-holding capacity, and encapsulation efficiency were evaluated.

RESULTS

The results indicated that the addition of FG could improve the transparency, rehydration, and water-holding capacity of FSDN. Scanning electronic microscope (SEM) images revealed that FSDN had a denser and more complete structure than SA. Encapsulation efficiency improved from 15.85% to 91.91% as the FG concentration ranged from 0 to 50 g/L. Bifidobacterium longum embedded by FSDN showed better thermal stability than when it was free. Compared with bare probiotics (1.7%), the encapsulated ones exhibited higher viability (above 15%) in simulated gastric fluid.

CONCLUSION

In conclusion, interpenetrating FSDN is an effective barrier constituent and could achieve the targeted delivery of probiotics. It is a potential new delivery carrier for the oral administration of probiotics. © 2021 Society of Chemical Industry.

Microencapsulation of Bioactive Ingredients for Their Delivery into Fermented Milk Products: A Review

The popularity and consumption of fermented milk products are growing. On the other hand, consumers are interested in health-promoting and functional foods. Fermented milk products are an excellent matrix for the incorporation of bioactive ingredients, making them functional foods. To overcome the instability or low solubility of many bioactive ingredients under various environmental conditions, the encapsulation approach was developed. This review analyzes the fortification of three fermented milk products, i.e., yogurt, cheese, and kefir with bioactive ingredients. The encapsulation methods and techniques alongside the encapsulant materials for carotenoids, phenolic compounds, omega-3, probiotics, and other micronutrients are discussed. The effect of encapsulation on the properties of bioactive ingredients themselves and on textural and sensory properties of fermented milk products is also presented.

Recombinant organophosphorus hydrolase (OPH) expression in E. coli for the effective detection of organophosphate pesticides

Accumulation and exposure of organophosphate pesticides are of great concern today owing to their abundant usage and potential health hazards. Harmful effects of organophosphate pesticide exposure and limitations of the available treatment methods necessitate the development of reliable, selective, cost-effective, and sensitive methods of detection. We developed a novel biosensor based on the enzymatic action of recombinant organophosphorus hydrolase (OPH) expressed in E. coli. We report the development of colorimetric biosensors made of His-Nus-OPH as well as His-Nus-OPH loaded alginate microspheres. The colorimetric detection method developed using solution-phase and alginate-encapsulated His-Nus-OPH exhibited detection limits of 0.045 and 0.039 mM, respectively, for ethyl paraoxon, and 0.101 and 0.049 mM, respectively, for methyl parathion. Additionally, fluorescence measurement using pH-sensitive fluorescein isothiocyanate (FITC) was used to sense the quantity of organophosphorus pesticides. The fluorometric detection method using solution-phase His-Nus-OPH, with ethyl paraoxon and methyl parathion as the substrate, reveals the lower limit of detection as 0.014 mM and 0.044 mM, respectively. Our results demonstrate the viability of His-Nus-OPH for OP detection with good sensitivity, LOD, and linear range. We report the first use of N-terminal His-NusA-tagged OPH, which enhances solubility significantly and presents a significant advance for the scientific community.

Hydrogel Encapsulation of Lactobacillus casei by Block Charge Modified Pectin and Improved Gastric and Storage Stability

Lactobacillus casei (L. casei W8) was encapsulated in pectin methylesterase (PME) charge modified pectin hydrogels; stability and in vitro release were evaluated under simulated gastrointestinal (GI) conditions. PME, 355 U/mL, de-esterified citrus pectin to 35% from 72% degree of esterification (DE). Pectin ζ-potential decreased to about −37 mV and molecular weight decreased from 177 kDa to 143 kDa during charge modification. More than 99% L. casei W8 were encapsulated in block charged, low methoxy pectin (35 mLMP) hydrogels by calcium ionotropic gelation. The integrity of the hydrogels was maintained under simulated GI conditions, and no release of L. casei W8 was observed. Microbial counts of encapsulated L. casei ranged from 6.94 log CFU/g to 10.89 log CFU/g and were 1.23 log CFU/g higher than for unencapsulated L. casei W8. The viability of encapsulated L. casei W8 in wet hydrogels remained the same for 2 weeks, but nearly all flora died after 4 weeks storage at 4 °C. However, freeze dried hydrogels of L. casei W8 were viable for 42 days at 4 °C and 14 days at room temperature. Charge modified pectin hydrogels are potentially good vehicles for colon-targeted delivery carrier for probiotics and longer stability of L. casei W8.

Impact of encapsulating probiotics with cocoa powder on the viability of probiotics during chocolate processing, storage, and in vitro gastrointestinal digestion

Chocolates can be formulated as a functional food via enrichment with probiotics. However, the added probiotics must overcome the challenges of processing and storage conditions and the harsh gastrointestinal environment. The study aimed to overcome these challenges using two different formulations of cocoa powder as alternative encapsulants along with Na-alginate (A₁ ) and Na-alginate and fructooligosaccharides (A₂ ). Seven different probiotic strains were encapsulated individually using the new formulations and viabilities of these encapsulated probiotics were assessed prior to and after they were added to chocolates. The highest achieved encapsulation efficiencies were 93.40% for formulation A₁ (with Lactobacillus casei) and 95.36% for formulation A₂ (with Lactobacillus acidophilus La5). The encapsulated probiotics with the new formulations maintained higher viability than the recommended therapeutic level (10⁷ colony forming unit [CFU]/g) for up to 180 and 120 days of storage at 4 and 25 °C, respectively. The tested encapsulants improved probiotics survival when subjected to thermal stress and maintained about 9.0 Logs CFU/g at 60 °C. Additionally, the viable numbers of probiotics in fortified chocolates showed higher than 7 Logs CFU/g after 90 days of storage at 25 °C. Both formulations exhibited significantly (P < 0.05) high survivability of probiotics (8.0 Logs CFU/g) during the in vitro gastrointestinal digestion. This study demonstrated that cocoa powder along with Na-alginate and FOS has the potential to be used as a probiotic encapsulating material, and chocolates could be an excellent carrier for the development of healthy probiotic chocolate products. PRACTICAL APPLICATION: The introduction of cocoa powder as an effective encapsulating agent to deliver probiotics could help the chocolate industry to develop healthy and attractive functional snacks for health-conscious consumers.

Herbal hydrogel-based encapsulated Enterococcus faecium ABRIINW.N7 improves the resistance of red hybrid tilapia against Streptococcus iniae

AIMS

The streptococcal disease has been associated with serious mortality and significant global economic loss in the tilapia farming industry. The overall goal of this work was to test herbal hydrogels based on encapsulated Enterococcus faecium ABRIINW.N7 for potential probiotic anti-microbial activity against Streptococcus iniae in red hybrid tilapia.

METHODS AND RESULTS

Abnormal behaviour, clinical signs, postinjection survival and histopathology (kidney, liver, eye and brain) were measured. Cumulative mortality of CON⁺ , free cells, ALG and treatments (F1-F7) was 30, 24, 22, 19, 17, 17, 16, 14, 14 and 12 out of 30 fish and the survival rates for E. faecium ABRIINW.N7 microencapsulated in an alginate-BS blend with 0·5, 1, 1·5, 2, 2·5 and 3% fenugreek were 43, 43, 47, 53, 53 and 60%, respectively. After the incorporation of fenugreek with the alginate-BS blend, there was an 8-21% increase in probiotic cell viability. Furthermore, the survival rate for the alginate-BS blend with 2·5 and 3% fenugreek (F6 and F7) was significantly (P ≤ 0·05) higher than other blends. The highest encapsulation efficiency, viability in gastrointestinal conditions and during storage time and excellent antipathogenicity against S. iniae were observed in alginate-BS +3% fenugreek formulation (F7).

CONCLUSIONS

It is recommended that probiotic strains like E. faecium ABRIINW.N7 in combination with local herbal gums, such as BS and fenugreek plus alginate, can be used as a suitable scaffold and an ideal matrix for the encapsulation of probiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study proposes models connecting process parameters, matrix structure and functionality.

Microencapsulation of Lactobacillus casei and Lactobacillus rhamnosus in pectin and pectin-inulin microgel particles: Effect on bacterial survival under storage conditions

The main objective of the research was to evaluate the performance of synbiotic delivery systems using pectin microgels on the protection of two probiotic strains (Lactobacillus casei ATCC 393 and Lactobacillus rhamnosus strain GG [ATCC 53103]) to simulated gastrointestinal digestion (GD) and storage conditions (4 ± 1 °C) in a 42 days trial. Microgel particles were prepared by ionotropic gelation method and three variables were evaluated: incubation time (24 and 48 h), free vs encapsulated cells, and presence or absence of prebiotic (commercial and Jerusalem artichoke inulin). Results demonstrated an encapsulation efficiency of 96 ± 4% into particles with a mean diameter between 56 and 118 μm. The viability of encapsulated cells after 42 days storage stayed above 7 log units, being encapsulated cells in pectin-inulin microgels more resistant to GD compared to non-encapsulated cells or without prebiotics. In all cases incubation time influenced the strains' survival.

Microencapsulation of Lactobacillus plantarum in W/O emulsions of okara oil and block-copolymers of poly(acrylic acid) and pluronic using microfluidic devices

Okara oil is a by-product remaining from defatting okara, the solid residue generated after extracting the aqueous fraction of grounded soybeans in the elaboration of soy beverages. The goal of this work was to encapsulate the probiotic Lactobacillus plantarum CIDCA 83114 into W/O emulsions composed of a block-copolymer constituted of pluronic® and acrylic acid (PPP12) and okara oil, prepared in microfluidic devices. For comparative purposes, alginate was also included as a second dispersed phase. Lactobacillus plantarum CIDCA 83114 was suspended in PPP12 or alginate giving rise to dispersed phases with different compositions, named I, II, III and IV. Controls were prepared by suspending microorganisms in water as dispersed phase. 6-carboxyfluorescein was added as bacterial marker in all the emulsions. The presence of green dyed bacteria in the dispersed phases, inside the droplets of the emulsions and the absence of fluorescence outside them, confirmed the complete encapsulation of bacteria in the dispersed phases. After being prepared, emulsions were freeze-dried. The exposure to gastric conditions did not lead to significant differences among the emulsions containing polymers. However, in all cases bacterial counts were significantly lower than those of the control. After exposing emulsions to the simulated intestinal environment, bacterial counts in assays I, II and III (emulsions composed of only one dispersed phase or of two dispersed phases with bacteria resuspended in the PPP12 one) were significantly greater than those of the control (p < 0.05) and no detectable microorganisms were observed for assay IV (emulsions composed of two dispersed phases with bacteria resuspended in the alginate one). In particular, bacterial cultivability in emulsions corresponding to assay I (only PPP12 as dispersed phase) exposed to the intestinal environment was 8.22 ± 0.02 log CFU/mL (2 log CFU higher than the values obtained after gastric digestion). These results support the role of PPP12 as an adequate co-polymer to protect probiotics from the gastric environment, enabling their release in the gut, with great potential for food or nutraceutical applications.

Incorporation of Bifidobacterium sp. into powder products through a fluidized bed process for enteric targeted release

Considering the increase in evidence regarding the benefits of probiotics on human health, there is interest in developing solid products with proper functional characteristics, such as temperature and pH stability, that can be added to oral solid dosage forms or to dairy products to release microorganisms directly at their site of action. The aim of this work was to develop a product with an enteric coat containing probiotics that is stable at room temperature and resists low pH to ensure that the probiotics are passed through the stomach and reach the colon. We obtained 2 enteric-release products based on the incorporation of Bifidobacterium sp. using commercial microcrystalline cellulose (BIP-Av) and prebiotic inulin (BIP-In) as cores. Both products had an initial concentration of approximately 1 × 10⁸ bifidobacteria per gram (cfu/g) and showed a suitable resistance to acid; complete release from the products at a pH of 7.5 was observed at 120 min for BIP-In and 180 min for BIP-Av. The viability of bacteria in both products decreased by approximately 3 orders of magnitude. The death rate constant corresponded to 0.1143 for BIP-Av and 0.1466 for BIP-In, which means that in these storage conditions, the viability decreased slightly. Both products protected bifidobacteria for more than 2 yr, delivering a concentration of more than 1 × 10⁵ cfu/g. Due to these characteristics, the products could be incorporated into solid pharmaceutical forms for oral administration. These products could have significant advantages over existing products on the market and provide protection for bacteria, allowing their passage through the stomach to reach the colon, and the viability of bacteria was maintained after storage at room temperature for more than 1 yr.

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.

Development of alginate-pectin microcapsules by the extrusion for encapsulation and controlled release of polyphenols from papaya (Carica papaya L.)

The papaya fruit (Carica papaya L.) contains a wide variety of bioactive compounds with potential applications in the food and nutraceutical industries. The entrapment and release of such bioactive compounds remain a critical step for the development of functional, stable, and cost-effective storage and delivery systems, since the interaction of polymers on capsules and the payload molecules can influence the performance of the capsule system under operational conditions. The present study describes the encapsulation of rutin and trans-ferulic acid-rich extracts from papaya exocarp in a pectin-alginate composite, evaluating the performance of gallic acid encapsulation obtained through in situ and two-step entrapment methods. The best alginate:pectin ratio for gallic acid encapsulation was 55:45 and 61:39, achieving 6.1 mg and 28.1 mg GAE/g capsules when the papaya exocarp extract was encapsulated by in situ and two-step, respectively. We also evaluated the payload release performance of the obtained capsules under in vitro conditions simulating gastrointestinal conditions. Our results indicate an increased protective effect at gastric pH and targeted release of polyphenols when in situ encapsulation is used to encapsulate the extracts. PRACTICAL APPLICATIONS: Currently, adding value to agroindustry processing waste is an important focus to achieve a more economically and environmentally sustainable food industry. The recovery of bioactive molecules such as polyphenols, for food supplements or formulation additives in the form of by-product extracts is gaining importance as novel sustainable processes in the agricultural industry. Thus, the encapsulation of such bioactive extracts for storage and consumption is an active research field, aiming to overcome the low storage stability and lability to gastric conditions, currently hindering their applications in food or pharmaceutical formulations. In this sense, capsule design and the development of efficient encapsulation methods are very important to obtain a suitable carrier and protector system for the capsulated bioactive extracts or molecules. This research aims to add value to papaya waste and potentially to other agroindustry wastes such as pectin and alginate, resulting in a polyphenol carrier with excellent encapsulation and targeted release properties under gastrointestinal conditions. In conclusion, this kind of works could allow to the application of the agroindustry byproducts to obtain high added-value products, in the form of polyphenol-loaded capsules.

Formulating bacterial endophyte: Pre-conditioning of cells and the encapsulation in amidated pectin beads

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Endophytic activity of pre-conditioned and encapsulated cells in amidated pectin beads

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Hydroxyectoine-added cells within pectin amidated beads increase endophytismus

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Radish yields increased through the application of encapsulated K. radicincitans cells

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Entrapped cells chemoattraction towards radish visualized by multispectral imaging

Despite the benefits of bacterial endophytes, recent studies on the mostly Gram-negative bacteria lack of regard for formulation strategies. The encapsulation into biopolymeric materials such as amidated pectins hydrogels is a suitable alternative. Here, this research aimed at supporting the capability of the plant growth-promoting bacteria Kosakonia radicincitans DSM16656^T to endophytically colonize plant seedlings. In this approach, the pre-conditioned cells through osmoadaptation and hydroxyectoine accumulation were used. In general, pre-osmoadapted and hydroxyectoine-supplemented bacteria cells formulated in amidated pectin dried beads increased the endophytic activity by 10-fold. Moreover, plant promotion in radish plants enhanced by 18.9% and 20.7% for a dry matter of tuber and leaves. Confocal microscopy studies with GFP-tagged bacteria revealed that bacterial aggregates formed during the activation of beads play an essential role in early colonization stages. This research encourages the integration of fermentation and formulation strategies in a bioprocess engineering approach for exploiting endophytic bacteria.