Protection of L. rhamnosus by spray-drying using two prebiotics colloids to enhance the viability

Application of inulin for the formulation and delivery of bioactive molecules and live cells

Inulin is a fructan biosynthesized mainly in plants of the Asteraceae family. It is also found in edible vegetables and fruits such as onion, garlic, leek, and banana. For the industrial production of inulin, chicory and Jerusalem artichoke are the main raw material. Inulin is used in the food, pharmaceutical, cosmetic as well biotechnological industries. It has a GRAS status and exhibits prebiotic properties. Inulin can be used as a wall material in the encapsulation process of drugs and other bioactive compounds and the development of their delivery systems. In the review, the use of inulin for the encapsulation of probiotics, essential and fatty oils, antioxidant compounds, natural colorant and other bioactive compounds is presented. The encapsulation techniques, materials and the properties of final products suitable for the delivery into food are discussed. Research limitations are also highlighted.

Effect and Mechanism of Soluble Starch on Bovine Serum Albumin Cold-Set Gel Induced by Microbial Transglutaminase: A Significantly Improved Carrier for Active Substances

Soluble starch (SS) could significantly accelerate the process of bovine serum albumin (BSA) cold-set gelation by glucono-δ-lactone (GDL) and microbial transglutaminase (MTGase) coupling inducers, and enhance the mechanical properties. Hardness, WHC, loss modulus (G″) and storage modulus (G') of the gel increased significantly, along with the addition of SS, and gelation time was also shortened from 41 min (SS free) to 9 min (containing 4.0% SS); the microstructure also became more and more dense. The results from FTIR, fluorescence quenching and circular dichroism (CD) suggested that SS could bind to BSA to form their composites, and the hydrogen bond was probably the dominant force. Moreover, the ability of SS to bind the original free water in BSA gel was relatively strong, thereby indirectly increasing the concentration of BSA and improving the texture properties of the gel. The acceleration of gelling could also be attributed to the fact that SS reduced the negative charge of BSA aggregates and further promoted the rapid formation of the gel. The embedding efficiency (EE) of quercetin in BSA-SS cold-set gel increased from 68.3% (SS free) to 87.45% (containing 4.0% SS), and a controlled-released effect was detected by simulated gastrointestinal digestion tests. The work could put forward new insights into protein gelation accelerated by polysaccharide, and provide a candidate for the structural design of new products in the food and pharmaceutical fields.

Influence of Lactose Supplementation on Regulation of Streptococcus thermophilus on Gut Microbiota

It has been found that Streptococcus thermophilus (S. thermophilus) influenced the gut microbiota and host metabolism with strain specificity in C57BL/6J mice in the previous study, though it remains unclear whether lactose as a dietary factor associated with dairy consumption is involved as the mediator in the interaction. In the present study, integrated analysis of 16S rRNA gene sequencing and untargeted metabolomics by liquid chromatography-mass spectrometry of fecal samples in C57BL/6J mice was applied to evaluate the effect of lactose on the regulation of gut microbiota by two S. thermophilus strains (4M6 and DYNDL13-4). The results showed that the influence of lactose supplementation on gut microbiota induced by S. thermophilus ingestion was strain-specific. Although two S. thermophilus strains ingestion introduced similar perturbations in the fecal microbiota and gut microbial metabolism, the regulation of DYNDL13-4 on the gut microbiota and metabolism was more affected by lactose than 4M6. More specifically, lactose and 4M6 supplementation mainly enriched pathways of d-glutamine and d-glutamate metabolism, alanine, aspartate, and glutamate metabolism, and tryptophan and phenylalanine metabolism in the gut, whereas 4M6 only enriched tryptophan and phenylalanine metabolism. DYNDL13-4-L (DYNDL13-4 with lactose) had significant effects on sulfur, taurine, and hypotaurine metabolism in the gut and on phenylalanine, tyrosine, tryptophan biosynthesis, and linoleic acid metabolism in serum relative to the DYNDL13-4. Our study demonstrated the strain-specific effect of lactose and S. thermophilus supplementation on gut microbiota and host metabolism. However, considering the complexity of the gut microbiota, further research is necessary to provide insights to facilitate the design of personalized fermented milk products as a dietary therapeutic strategy for improving host health.

Process and formulation parameters influencing the survival of Saccharomyces cerevisiae during spray drying and tableting

Probiotic microorganisms provide health benefits to the patient when administered in a viable form and in sufficient doses. To ensure this, dry dosage forms are preferred, with tablets in particular being favored due to several advantages. However, the microorganisms must first be dried as gently as possible. Here, the model organism Saccharomyces cerevisiae was dried by spray drying. Various additives were tested for their ability to improve yeast cell survival during drying. In addition, the influence of various process parameters such as inlet temperature, outlet temperature, spray rate, spray pressure and nozzle diameter was investigated. It was possible to dry the yeast cells in such a way that a substantial proportion of living microorganisms was recovered after reconstitution. Systematic variation of formulation and process parameters showed that the use of protective additives is essential and that the outlet temperature determines the survival rate. The subsequent compression of the spray-dried yeast reduced viability and survival could hardly be improved by the addition of excipients, but the tabletability of spray-dried yeast protectant particles was quite good. For the first time, loss of viability during compaction of spray-dried microorganisms was correlated with the specific densification, allowing a deeper understanding of the mechanism of cell inactivation during tableting.

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

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

Whey protein hydrolysates as prebiotic and protective agent regulate growth and survival of Lactobacillus rhamnosus CICC22152 during spray/freeze-drying, storage and gastrointestinal digestion

BACKGROUND

Probiotic products are receiving increasing attention because of their tremendous beneficial health effects. However, it is still a great challenge to preserve probiotic viability during processing, storage and gastrointestinal digestion. Encapsulation is a widely known technology for enhancing bacterial viability and product stability. Hence highly hydrolyzed whey protein hydrolysate (HWPH) and moderately hydrolyzed whey protein hydrolysate (MWPH) used as a one-step culture medium and wall material for Lactobacillus rhamnosus were investigated.

RESULTS

H/MWPH-substitutive medium for the growth of Lactobacillus rhamnosus presented double the biomass production compared to other media. The H/MWPH-substitutive medium in combination with freeze drying also led to the highest survival ratio (97.13 ± 9.16%) and cell viability (10.62 log CFU g^-1 ). The highest survival rate of spray-dried cells was 85.56 ± 7.4%. In addition, the cell viability of spray-dried Lactobacillus rhamnosus with MWPH as culture and dry medium was 0.79 log CFU g^-1 higher than that of HWPH. Images confirmed that spray-dried Lactobacillus rhamnosus in MWPH provided better protection and it showed greater sustained viability after gastrointestinal digestion.

CONCLUSION

Overall, WPH just as carrier provides better thermal protection and MWPH is a preferable two-in-one medium for probiotics. © 2022 Society of Chemical Industry.

Hydrolytic Quinoa Protein and Cationic Lotus Root Starch-Based Micelles for Co-Delivery of Quercetin and Epigallo-catechin 3-Gallate in Ulcerative Colitis Treatment

The accumulation and sustained release of drugs in the colonic inflammatory region are the favorable strategy for treating ulcerative colitis (UC). In this study, we developed a synergistic anti-inflammatory drug (quercetin/EGCG)-loaded micelle using hydrolytic quinoa protein (HQP) and cationic lotus root starch (CLRS) by a layer-by-layer assembly method. The encapsulation efficiency of quercetin and EGCG in the Que-HQP-EGCG-CLRS micelles reached 91.5 and 89.4%, respectively. This composite micelle exhibited a core-shell structure, where Que-HQP-EGCG was the core and CLRS was the coating shell. Moreover, the in vitro experiments indicated that these micelles can make Que/EGCG pass through gastric environments stably and delay their release in the intestine. Animal experiments further confirmed that the Que-HQP-EGCG-CLRS micelles can efficiently accumulate in the colonic inflammatory region and enable sustained release of drugs (more than 24 h), thus notably alleviating the symptoms of UC. These results suggested that Que-HQP-EGCG-CLRS micelles have good gastric stability, colonic inflammatory-accumulated effect, and sustained drug release ability, which are a promising co-delivery system for UC treatment.

Kinetics and Mechanisms of Saccharomyces boulardii Release from Optimized Whey Protein-Agavin-Alginate Beads under Simulated Gastrointestinal Conditions

Encapsulation is a process in which a base material is encapsulated in a wall material that can protect it against external factors and/or improve its bioavailability. Among the different encapsulation techniques, ionic gelation stands out as being useful for thermolabile compounds. The aim of this work was to encapsulate Saccharomyces boulardii by ionic gelation using agavins (A) and whey protein (WP) as wall materials and to evaluate the morphostructural changes that occur during in vitro gastrointestinal digestion. Encapsulations at different levels of A and WP were analyzed using microscopic, spectroscopic and thermal techniques. Encapsulation efficiency and cell viability were evaluated. S. boulardii encapsulated at 5% A: 3.75% WP (AWB6) showed 88.5% cell survival after the simulated gastrointestinal digestion; the bead showed a significantly different microstructure from the controls. The mixture of A and WP increased in the survival of S. boulardii respect to those encapsulated with alginate, A or WP alone. The binary material mixture simultaneously allowed a controlled release of S. boulardii by mostly diffusive Fickian mechanisms and swelling. The cell-release time was found to control the increment of the Damköhler number when A and WP were substrates for S. boulardii, in this way allowing greater protection against gastrointestinal conditions.

Current Trends in the Production of Probiotic Formulations

Preparations containing probiotic strains of bacteria have a beneficial effect on human and animal health. The benefits of probiotics translate into an increased interest in techniques for the preservation of microorganisms. This review compares different drying methods and their improvements, with specific reference to processing conditions, microorganisms, and protective substances. It also highlights some factors that may influence the quality and stability of the final probiotic preparations, including thermal, osmotic, oxidative, and acidic stresses, as well as dehydration and shear forces. Processing and storage result in the loss of viability and stability in probiotic formulations. Herein, the addition of protective substances, the optimization of process parameters, and the adaptation of cells to stress factors before drying are described as countermeasures to these challenges. The latest trends and developments in the fields of drying technologies and probiotic production are also discussed. These developments include novel application methods, controlled release, the use of food matrices, and the use of analytical methods to determine the viability of probiotic bacteria.

Sucrose, maltodextrin and inulin efficacy as cryoprotectant, preservative and prebiotic – towards a freeze dried Lactobacillus plantarum topical probiotic

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Saccharides assessed as combined cryoprotectant, preservative and prebiotic.

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Application is freeze dried topical probiotic of Lactobacillus plantarum.

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Inulin was best as cryoprotectant, but did not protect cells over storage.

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Best combined performance using sucrose with storage at 4 °C.

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Room temperature storage only feasible with skimmed milk (positive control).

Probiotic formulations must contain the right strain(s) in sufficient numbers when administered to confer the desired health benefit. However, significant cell death can occur during freeze-drying and over storage. This study assesses various saccharides for their ability to protect Lactobacillus plantarum cells over freeze-drying and storage, as well as their potential to act as prebiotics. The cryoprotective potential of 10% (m/v) of skimmed milk, inulin, maltodextrin, and sucrose were investigated during freeze-drying. Storage was assessed over 12 weeks at 4 °C and room temperature. Improved cell survival over freeze drying was observed with all the saccharides. However, only maltodextrin and sucrose retained cell viability over storage at 4 °C. Overall, skimmed milk demonstrated the highest survival up to 91%. Despite good cryoprotectant performance, inulin provided the least protection over storage, with <1% cell survival. Prebiotic potential was determined through growth experiments with 2% (m/v) of the saccharides in glucose-free MRS. All saccharides supported cell growth, with sucrose performing best and inulin worst.

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.

Polysaccharide Hydrogels for the Protection of Dairy-Related Microorganisms in Adverse Environmental Conditions

Adverse environmental conditions are severely limiting the use of microorganisms in food systems, such as probiotic delivery, where low pH causes a rapid decrease in the survival of ingested bacteria, and mixed-culture fermentation, where stepwise changes and/or metabolites of individual microbial groups can hinder overall growth and production. In our study, model probiotic lactic acid bacteria (L. plantarum ATCC 8014, L. rhamnosus GG) and yeasts native to dairy mixed cultures (K. marxianus ZIM 1868) were entrapped in an optimized (cell, alginate and hardening solution concentration, electrostatic working parameters) Ca-alginate system. Encapsulated cultures were examined for short-term survival in the absence of nutrients (lactic acid bacteria) and long-term performance in acidified conditions (yeasts). In particular, the use of encapsulated yeasts in these conditions has not been previously examined. Electrostatic manufacturing allowed for the preparation of well-defined alginate microbeads (180–260 µm diameter), high cell-entrapment (95%) and viability (90%), and uniform distribution of the encapsulated cells throughout the hydrogel matrix. The entrapped L. plantarum maintained improved viabilities during 180 min at pH 2.0 (19% higher when compared to the free culture), whereas, L. rhamnosus appeared to be less robust. The encapsulated K. marxianus exhibited double product yields in lactose- and lactic acid-modified MRS growth media (compared to an unfavorable growth environment for freely suspended cells). Even within a conventional encapsulation system, the pH responsive features of alginate provided superior protection and production of encapsulated yeasts, allowing several applications in lacto-fermented or acidified growth environments, further options for process optimization, and novel carrier design strategies based on inhibitor charge expulsion.

The Application of Spray-Dried and Reconstituted Flaxseed Oil Cake Extract as Encapsulating Material and Carrier for Probiotic Lacticaseibacillus rhamnosus GG

Agro-industrial by-products are promising source of biopolymers, including proteins and polysaccharides. This study was designed to evaluate the flaxseed oil cake extract (FOCE) as natural encapsulating material and carrier for probiotic Lacticaseibacillus rhamnous GG (LGG). The powders were obtained using three spray drying inlet temperatures (110 °C, 140 °C, 170 °C), and reconstituted. The influence of temperature on water activity, morphology, chemical composition, flowability and cohesiveness of the powders was estimated. For all variants, the survival of bacteria during spray drying, and simulated passage through the gastrointestinal tract was evaluated. The preservation of LGG probiotic features such as cholesterol reduction, hydrophobicity and adhesion to mucin were examined. Results revealed that all physicochemical and functional characteristics of the powders were affected by the inlet temperature. This study demonstrated that FOCE is an appropriate matrix for spray drying (due to flaxseed proteins and polysaccharides) providing high survivability of bacteria (89.41-96.32%), that passed meaningfully through the simulated gastrointestinal tract (4.39-5.97 log reduction), largely maintaining their probiotic properties, being a promising environmentally-friendly carrier for probiotic LGG.

Role of prebiotics in enhancing the function of next-generation probiotics in gut microbiota

With the development of high-throughput DNA sequencing and molecular analysis technologies, next-generation probiotics (NGPs) are increasingly gaining attention as live bacterial therapeutics for treatment of diseases. However, compared to traditional probiotics, NGPs are much more vulnerable to the harsh conditions in the human gastrointestinal tract, and their functional mechanisms in the gut are more complex. Prebiotics have been confirmed to play a critical role in improving the function and viability of traditional probiotics. Defined as substrates that are selectively utilized by host microorganisms conferring a health benefit, prebiotics are also important for NGPs. This review summarizes potential prebiotics for use with NGPs and clarifies their characteristics and functional mechanisms. Then we particularly focus on illustrating the protective effects of various prebiotics by enhancing the antioxidant capacity and their resistance to digestive fluids. We also elucidate the role of prebiotics in regulating anti-bacterial effects, intestinal barrier maintenance, and cross-feeding mechanisms of NPGs. With the expanding range of candidate NGPs and prebiotic substrates, more studies need to be conducted to comprehensively elucidate the interactions between prebiotics and NGPs outside and inside hosts, in order to boost their nutritional and healthcare applications.

The efficacy of three double-microencapsulation methods for preservation of probiotic bacteria

Lactic acid bacteria (LAB) are used as a probiotic alternative to antibiotics in livestock production. Microencapsulation technology is widely used for probiotic preservation. A variety of microencapsulation protocols have been proposed and compared based on chemicals and mechanical procedures. This study aimed to develop a double-encapsulated coating from alginate (1.5%) and chitosan (0.5%) by extrusion, emulsion, and spray drying methods using the LAB strains Lactobacillus plantarum strains 31F, 25F, 22F, Pediococcus pentosaceus 77F, and P. acidilactici 72N, and to monitor the basic probiotic properties of the encapsulated prototypes. The final products from each microencapsulation protocol were analysed for their appearance, probiotic properties and viable cell count. Using the spray drying method, particles smaller than 15 μm in diameter with a regular spherical shape were obtained, whereas the other methods produced larger (1.4–52 mm) and irregularly shaped microcapsules. After storage for 6 months at room temperature, the LAB viability of the spray-dried particles was the highest among the three methods. In all the LAB strains examined, the encapsulated LAB retained their probiotic properties in relation to acid-bile tolerance and antibacterial activity. This study highlights the efficacy of double-coating microencapsulation for preserving LAB properties and survival rate, and demonstrates its potential for probiotic application in livestock farms.

A Review of the Extraction and Closed-Loop Spray Drying-Assisted Micro-Encapsulation of Algal Lutein for Functional Food Delivery

In this study, the physical and chemical properties and bioavailability of lutein have been summarized, with the novelty of this work being the review of lutein from production to extraction, through to preservation and drying, in order to deliver a functional food ingredient. The potential health functions of lutein have been introduced in detail. By comparing algae and marigold flowers, the advantages of algae extraction technology have been discussed. In this article, we have introduced the use of closed-loop spray drying technology to microencapsulate lutein to improve its stability and solubility. Microencapsulation of unstable substances by spray drying is a potentially useful direction that is worth exploring further.

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

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

Microencapsulation of Lactobacillus rhamnosus ATCC 7469 by spray drying using maltodextrin, whey protein concentrate and trehalose

This study aimed to microencapsulate Lactobacillus rhamnosus (L. rhamnosus) ATCC 7469 with whey protein concentrate (WPC), maltodextrin and trehalose by spray drying and to assess the impact of microencapsulation on cell viability and the properties of the dried powders. Spray-drying conditions, including inlet air temperature, air flow rate and feed pump, were fixed as independent variables, while probiotic survival, moisture content, water activity and effective yield were established as dependent variables. The survival of encapsulated L. rhamnosus by spray drying was optimized with response surface methodology, and the stability of the powder was assessed. The optimum spray-drying conditions were an inlet air temperature, air flow rate and feed pump rate of 169 °C, 33 m³·h^-1 and 16 mL·min^-1, respectively, survival of 70%, air aspiration of 84% and outlet air temperature of 52 °C, achieving an overall desirability of 0.96. The physicochemical and structural characteristics of the produced powder were acceptable for application with regard to residual water content, hygroscopicity, water activity, and particle size. The results indicated that a protein-trehalose-maltodextrin mixture is a good wall material to encapsulate L. rhamnosus, showing important thermal protection during the drying process and increasing survival. However, a decrease in this capacity is observed at an air outlet temperature of approximately 101 °C. The possible effects of the wall materials and the drying conditions on survival are also discussed.

Targeted Delivery of Probiotics: Perspectives on Research and Commercialization

Considering the significance of the gut microbiota on human health, there has been ever-growing research and commercial interest in various aspects of probiotic functional foods and drugs. A probiotic food requires cautious consideration in terms of strain selection, appropriate process and storage conditions, cell viability and functionality, and effective delivery at the targeted site. To address these challenges, several technologies have been explored and some of them have been adopted for industrial applicability. Encapsulation of probiotics has been recognized as an effective way to stabilize them in their dried form. By conferring a physical barrier to protect them from adverse conditions, the encapsulation approach renders direct benefits on stability, delivery, and functionality. Various techniques have been explored to encapsulate probiotics, but it is noteworthy that the encapsulation method itself influences surface morphology, viability, and survivability of probiotics. This review focuses on the need to encapsulate probiotics, trends in various encapsulation techniques, current research and challenges in targeted delivery, the market status of encapsulated probiotics, and future directions. Specific focus has been given on various in vitro methods that have been explored to better understand their delivery and performance.

Effect of co-encapsulation using a calcium alginate matrix and fructooligosaccharides with gelatin coating on the survival of Lactobacillus paracasei cells

The demand for functional foods is increasing each year because consumers are gaining awareness about the importance of a healthy diet in the proper functioning of the body. Probiotics are among the most commonly known, commercialized, and studied foods. However, the loss of viability of probiotic products is observed during their formulation, processing, and storage. This study aimed to investigate the co-encapsulation of two Lactobacillus paracasei probiotic strains (LBC81 and ELBAL) with fructooligosaccharides (FOS) in a calcium alginate matrix using extrusion technology with gelatin as a coating material. The viability of the strains under gastrointestinal conditions and in storage at low temperature was also assessed. An immobilization yield of more than 59% was observed for both bacterial strains. Exposure to 2% biliary salts led to a decrease in the viability of free cells in the two L. paracasei strains, whereas the viability of microencapsulated cells increased up to 47%. After 35 days of storage at 4°C, the population of free cells was reduced, but microencapsulated cells remained stable after storage at low temperature. LBC81 bacteria microencapsulated with 1.5% FOS coated with gelatin were the most resistant to the stressful environments tested. Therefore, these results showed that co-encapsulation with FOS in a calcium alginate matrix coated with gelatin improved L. paracasei survival and may be useful for the development of more resistant probiotics and new functional foods.

Improving the survival of Lactobacillus plantarum NRRL B-1927 during microencapsulation with ultra-high-pressure-homogenized soymilk as a wall material

Probiotic foods and supplements have been shown to offer multiple potential health benefits to consumers. Dried probiotic cultures are increasingly used by the food industry because they are easily handled, transported, stored, and used in different applications. However, drying technologies often expose probiotic cells to extreme environmental conditions that reduces cell viability. Hence, this study aimed to evaluate the effect of using ultra high-pressure homogenization (UHPH) on soymilk's microencapsulating ability, and the resultant effect on the survivability of probiotic Lactobacillus plantarum NRRL B-1927 (LP) during drying. Liquid suspensions containing LP (~10⁹ CFU/g of solids) were prepared by suspending LP cultures in soymilk which had been either treated with UHPH at 150 MPa or 300 MPa or left untreated. LP suspensions were then dried by concurrent spray drying (CCSD), mixed-flow spray drying (MXSD) or freeze-drying (FD). Cell counts of LP were determined before and after microencapsulation. Moisture, water activity, particle size and morphology of LP powders were also characterized. LP powders produced with 300 MPa treated soymilk had 8.7, 6.4, and 2 times more cell counts than those produced with non-UHPH treated soymilk during CCSD, MXSD, and FD, respectively. In the 300 MPa treated samples, cell survival (%) of LP during drying was the highest in MXSD (83.72) followed by FD (76.31) and CCSD (34.01). Using soymilk treated at higher UHPH pressures resulted in LP powders with lower moisture content, smaller particle sizes and higher agglomeration. LP powders produced via MXSD showed higher agglomeration and fewer signs of thermal damage than powders produced via CCSD. This study demonstrates that UHPH improves the effectiveness of soymilk as a microencapsulant for probiotics, creating probiotic powders that could be used in plant-based and non-dairy foods.

Spray drying studies of probiotic Enterococcus strains encapsulated with whey protein and maltodextrin

Background

Probiotic Enterococcus strains of human origin were microencapsulated by spray drying using whey protein and maltodextrin as an encapsulating agent. The obtained encapsulates were characterized for stability, viability, and physiological properties.

Results

The microcapsules were prepared from probiotic Enterococcus strains that were previously isolated from human vagina and infants’ meconium. The microcapsules revealed similar particle sizes and morphologies. The highest hygroscopicity was observed in the microcapsules produced with strain E. rivorum S22C (0.17 ± 1.15) g water/kg powder/min. E. canintestini S18A revealed highest dissolution time in water (703 ± 2 s). The DSC thermogram revealed excellent thermal stability of all microcapsules. The physicochemical and morphological characteristics of the microcapsules were acceptable with regard to residual water content, particle mean size, and thermophysical properties and storage stability under room temperature conditions, with a low inactivation rate of Enterococcus strains. All the microcapsules revealed the recommended count of probiotic cells, low moisture content with low water activity. Observation under a scanning electron microscope revealed spherical-shaped partially collapsed structures measuring between 9 and 14 μm with surface concavities.

Conclusions

The microcapsule probiotic strains of Enterococcus microencapsulated by spray drying using whey protein and maltodextrin revealed properties of acceptable standards. These strains can have future potential as developing probiotic animal feed and food industry.

Microencapsulation of Lactobacillus plantarum NRRL B-1927 with Skim Milk Processed via Ultra-High-Pressure Homogenization

Several health benefits are associated with the consumption of probiotic foods. Lyophilized probiotic cultures are commonly used to manufacture probiotic-containing products. Spray drying (SDR) is a cost-effective process to microencapsulate probiotics. However, the high temperatures of the drying air in SDR can inactivate significant numbers of probiotic cells. Ultra-high-pressure homogenization (UHPH) processing can modify the configuration of proteins found in skim milk which may increase its protective properties as microencapsulating agent towards probiotic cells during SDR. The aim of this study was to evaluate the effect of microencapsulating probiotic Lactobacillus plantarum NRRL B-1927 (LP) with UHPH-treated skim milk after SDR or freeze drying (FD). Dispersions containing LP were made with either UHPH-treated (at 150 MPa or 300 MPa) or untreated skim milk and dried via concurrent SDR (CCSD), mixed-flow SDR (MXSD) or FD. Higher cell survival (%) of LP was found in powders microencapsulated with 150 MPa-treated skim milk than in those microencapsulated with non-UHPH-treated and 300 MPa-treated skim milk via FD followed by MXSD and CCSD, respectively. Increasing UHPH pressures increased the particle size of powders produced via CCSD; and reduced particle agglomeration of powders produced via MXSD and FD. This study demonstrated that UHPH processes improves the effectiveness of skim milk as a microencapsulating agent for LP, creating powders that could be used in probiotic foods.

Microencapsulation of Probiotic Strains by Lyophilization Is Efficient in Maintaining the Viability of Microorganisms and Modulation of Fecal Microbiota in Cats

High extrusion temperatures may compromise the functionality of probiotics in dry food. This study aimed to (i) evaluate the effects of two types of microencapsulation techniques, different encapsulating agents, and 120 days of storage on the viability of a commercial probiotic product and (ii) investigate fecal microbiota populations and fecal characteristics of adult cats fed with diets supplemented with probiotics. Three experimental treatments were evaluated: T1, commercial feed (control); T2, commercial kibbles coated with probiotics; and T3, commercial feed supplemented with freeze-dried probiotics and fructooligosaccharides. Fructooligosaccharides and gum arabic were used as encapsulating agents for freeze drying and spray drying and a pool containing Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus lactis, Bifidobacterium bifidum, Enterococcus faecium, and Saccharomyces cerevisiae as a probiotic. Diets were provided to 18 adult cats for 20 days. Feed samples were evaluated microbiologically, and feces were characterized according to their microbial content, pH, and fecal score. Freeze drying was more effective in maintaining microbial viability. Microcapsules prepared using fructooligosaccharides as encapsulants had the highest bacterial count: 8.74 log CFU/g of lactic acid bacteria and 8.75 log CFU/g of enterococci. Probiotics and synbiotics positively modulated (P < 0.05) the fecal microbiota of cats, increasing the lactic acid bacteria counts from 3.65 to 4.87 and 5.07 log CFU/g, respectively. Microbial viability decreased significantly (P < 0.05) after storage, demonstrating the need for effective protection mechanisms against extrinsic agents. In conclusion, the supplementation of cat diets with probiotics positively affected the gut microbiota. However, the results reinforce that probiotic microorganisms must be incorporated into the animal feed via effective mechanisms to withstand harsh processing conditions and storage.

Effect of Three Polysaccharides (Inulin, and Mucilage from Chia and Flax Seeds) on the Survival of Probiotic Bacteria Encapsulated by Spray Drying

Chia seed mucilage (CM), flaxseed mucilage (FM), and inulin (INL) were used as encapsulating agents to evaluate the possibility of increasing the survival of Lactobacillus casei var. rhamnosus, renamed recently to Lacticaseibacillus rhamnosus, after spray drying. Moreover, the viability of encapsulated L. rhamnosus was determined during the 250 day storage period at 4 °C. In a second stage, the conditions that maximized the survival of L. rhamnosus were evaluated on other probiotic bacteria (Lactiplantibacillus plantarum, Bifidobacterium infantis, and Bifidobacterium longum). Additionally, the viability of encapsulated probiotics during the 60 day storage period at 4 and 25 °C was evaluated. The conditions that maximize the survival of L. rhamnosus (90%) predicted by a face-centered central composite design were 14.4% w/v of maltodextrin, 0.6% w/v of CM, and 90 °C of inlet air temperature. Additionally, under these encapsulating conditions, the survival of L. plantarum, B. infantis, and B. longum was 95%, 97%, and 96%, respectively. The probiotic viability improved during storage at 4 °C but decreased at 25 °C. The highest viability values obtained for probiotics during spray drying and during storage suggest a thermoprotector effect of CM, which would ensure an optimal probiotic efficacy in the product, thus promoting its utilization in the food industry.

The Inoculation of Probiotics In Vivo Is a Challenge: Strategies to Improve Their Survival, to Avoid Unpleasant Changes, or to Enhance Their Performances in Beverages

The inoculation of probiotics in beverages (probiotication) requires special technologies, as probiotic microorganisms can experience stress during food processing (acid, cold, drying, starvation, oxidative, and osmotic stresses) and gastrointestinal transit. Survival to harsh conditions is an essential prerequisite for probiotic bacteria before reaching the target site where they can exert their health promoting effects, but several probiotics show a poor resistance to technological processes, limiting their use to a restricted number of food products. Therefore, this paper offers a short overview of the ways to improve bacterial resistance: by inducing a phenotypic modification (adaptation) or by surrounding bacteria through a physical protection (microencapsulation). A second topic briefly addressed is genetic manipulation, while the last section addresses the control of metabolism by attenuation through physical treatments to design new kinds of food.

The Combined Usage of β-Cyclodextrin and Milk Proteins in Microencapsulation of Bifidobacterium bifidum BB-12

The present study aimed to determine the effects of combined usage of β-cyclodextrin with whey protein isolate and sodium caseinate on the microencapsulation of Bifidobacterium bifidum-BB12 by spray drying.From the results, the highest count of B. bifidum was provided by whey protein isolate as 8.62 log CFU/g. The increasing concentration of β-cyclodextrin considerably increases gastric and intestinal resistance to B. bifidum cells. In the gastric and intestinal test, the highest protection was determined in whey protein isolate substituted with 10% β-cyclodextrin with reduction rates of 0.98 and 3.30%, respectively. Moreover, free cells did not survive in the same gastric conditions. The lowest hygroscopicity was determined in whey protein isolate as 8.57%. It must be noted that increasing β-cyclodextrin concentration in carrier material combination led to an increase in hygroscopicity of microcapsules. In general, substitution with β-cyclodextrin increased the particle size of microparticles, and microcapsules produced with whey protein isolate had a smaller size than that of sodium caseinate.

Probiotics in Food Systems: Significance and Emerging Strategies Towards Improved Viability and Delivery of Enhanced Beneficial Value

Preserving the efficacy of probiotic bacteria exhibits paramount challenges that need to be addressed during the development of functional food products. Several factors have been claimed to be responsible for reducing the viability of probiotics including matrix acidity, level of oxygen in products, presence of other lactic acid bacteria, and sensitivity to metabolites produced by other competing bacteria. Several approaches are undertaken to improve and sustain microbial cell viability, like strain selection, immobilization technologies, synbiotics development etc. Among them, cell immobilization in various carriers, including composite carrier matrix systems has recently attracted interest targeting to protect probiotics from different types of environmental stress (e.g., pH and heat treatments). Likewise, to successfully deliver the probiotics in the large intestine, cells must survive food processing and storage, and withstand the stress conditions encountered in the upper gastrointestinal tract. Hence, the appropriate selection of probiotics and their effective delivery remains a technological challenge with special focus on sustaining the viability of the probiotic culture in the formulated product. Development of synbiotic combinations exhibits another approach of functional food to stimulate the growth of probiotics. The aim of the current review is to summarize the strategies and the novel techniques adopted to enhance the viability of probiotics.