Encapsulation of Pediococcus acidilactici cells in corn and olive oil microcapsules emulsified by peptides and stabilized with xanthan in oil-in-water emulsions: Studies on cell viability under gastro-intestinal simulating conditions

Harnessing Fermented Soymilk Production by a Newly Isolated Pediococcus acidilactici F3 to Enhance Antioxidant Level with High Antimicrobial Activity against Food-Borne Pathogens during Co-Culture

In this study, a newly isolated Pediococcus acidilactici F3 was used as probiotic starter for producing fermented soymilk to enhance antioxidant properties with high antimicrobial activity against food-borne pathogens. The objectives of this study were to investigate optimized fermentation parameters of soymilk for enhancing antioxidant property by P. acidilactici F3 and to assess the dynamic antimicrobial activity of the fermented soymilk during co-culturing against candidate food-borne pathogens. Based on central composite design (CCD) methodology, the maximum predicted percentage of antioxidant activity was 78.9% DPPH inhibition. After model validation by a 2D contour plot, more suitable optimum parameters were adjusted to be 2% (v/v) inoculum and 2.5 g/L glucose incubated at 30 °C for 18 h. These parameters could provide the comparable maximum percentage of antioxidant activity at 74.5 ± 1.2% DPPH inhibition, which was up to a 23% increase compared to that of non-fermented soymilk. During 20 days of storage at 4 °C, antioxidant activities and viable cells of the fermented soymilk were stable while phenolic and organic contents were slightly increased. Interestingly, the fermented soymilk completely inhibited food-borne pathogens, Salmonella Typhimurium ATCC 13311, and Escherichia coli ATCC 25922 during the co-culture incubation. Results showed that the soymilk fermented by P. acidilactici F3 may be one of the alternative functional foods enriched in probiotics, and the antioxidation and antimicrobial activities may retain nutritional values and provide health benefits to consumers with high confidence.

Long-Term Lacticaseibacillus rhamnosus GG Storage at Ambient Temperature in Vegetable Oil: Viability and Functional Assessments

Vegetable oils with varying saturated fat levels were inoculated with Lacticaseibacillus rhamnosus GG (LGG), subjected to different heat treatments in the absence and presence of inulin and stored for 12 months at room temperature. After storage, the heat-treated probiotics actively grew to high concentrations after removal of the oils and reculturing. The bacterial samples, regardless of aerobic or anaerobic conditions and treatment methods, showed no changes in their growth behavior. The random amplified polymorphic DNA-polymerase chain reaction, antimicrobial, morphology, and motility tests also showed no major differences. Samples of LGG treated with a higher antioxidant content (Gal400) showed reduced inflammatory and anti-inflammatory properties. These findings have been confirmed by metabolite and genome sequencing studies, indicating that Gal400 showed lower concentrations and secretion percentages and the highest number of single nucleotide polymorphisms. We have shown proof of concept that LGG can be stored in oil with minimum impact on probiotic in vitro viability.

Bifidobacterium Treated by Electrostatic Spray Drying Relieved Constipation by Changing the Relative Abundance of Bacteria Associated With Gastrointestinal Regulatory Peptides

In this study, three different microencapsulation methods were used to embed Bifidobacterium to explore the alleviating effects of embedding methods on constipated mice. By measuring the defecation-related parameters, it was found that the Bifidobacteria treated by electrostatic spray drying had the best ability to relieved constipation. Furthermore, by detecting constipation-related gastrointestinal regulatory peptides, inflammatory factors, intestinal microbiota, and SCFAs, it was discovered that Bifidobacteria treated by electrostatic spray drying changed the composition of intestinal microbiota, especially the relative abundance of bacteria that were positively correlated with AQP3, but negatively correlated with ET-1 and SS, then increased the level of AQP3 in the intestine, and finally relieved constipation by increasing the fecal water content and small intestinal propulsion rate. In conclusion, the electrostatic spray drying method was superior to the other two methods in maintaining the activity of Bifidobacteria and relieved constipation by changing the relative abundance of bacteria that were correlated with gastrointestinal regulatory peptides and increasing the content of fecal water and small intestinal propulsion rate.

Improved protective and controlled releasing effect of fish oil microcapsules with rice bran protein fibrils and xanthan gum as wall materials

This study aimed to prepare fish oil microcapsules by freeze-drying an emulsion co-stabilized by rice bran protein fibrils (RBPFs) and xanthan gum (XG) to improve the oxidation stability and controlled release effect. Emulsions stabilized either solely by RBPFs or unfibrillated rice bran protein (RBP) or by a combination of RBP and XG were also fabricated as microcapsule templates for comparison. The rheological properties, particle size, and zeta potential of the emulsions were examined. In addition, the characteristics of the fish oil microcapsules such as surface oil content, encapsulation efficiency, water activity, moisture content, morphological structure, oxidation stability, and digestive performance were also assessed. The rheological properties revealed that the addition of XG increased the storage modulus of the emulsion and reduced the loss modulus and apparent viscosity. At shear rates of 0-100 s^-1, the fish oil emulsion did not exhibit any gel properties or shear thinning. Fibrillation increased the particle size of the fish oil emulsion, whereas adding XG reduced the droplet size. The combination of RBP fibrillation and XG addition provided the highest encapsulation efficiency for fish oil. Fibrillation reduced the water activity and moisture content of the fish oil microcapsules. The anisotropy of the fibrils and the high viscosity of XG produced a layer of wrapping on the continuous heterogeneous surface of the freeze-dried powder particles. RBPF/XG microcapsules stored at 45 °C for 1 month had the lowest peroxide value and thiobarbituric acid value, the lowest surface oil content, and the lightest yellowness. These results suggest that the combination of RBPFs and XG provides better encapsulation and protective effects for fish oil microcapsules. Upon simulated digestion, the microcapsules containing XG and RBPFs exhibited a more favorable controlled release of free fatty acids. These findings indicate that microcapsules formed from emulsions co-stabilized by XG and RBPFs are suitable for encapsulating fish oil in functional foods.

Microencapsulation of Caramel Flavor and Properties of Ready-to-drink Milk Beverages Supplemented with Coffee Containing These Microcapsules

This study aimed to extend the retention of flavor in coffee-containing milk beverage by microencapsulation. The core material was caramel flavor, and the primary and secondary coating materials were medium-chain triglyceride and maltodextrin, respectively. Polyglycerol polyricinoleate was used as the primary emulsifier, and the secondary emulsifier was polyoxyethylene sorbitan monolaurate. Response surface methodology was employed to determine optimum microencapsulation conditions, and headspace solid-phase microextraction was used to detect the caramel flavor during storage. The microencapsulation yield of the caramel flavor increased as the ratio of primary to secondary coating material increased. The optimum ratio of core to primary coating material for the water-in-oil (W/O) phase was 1:9, and that of the W/O phase to the secondary coating material was also 1:9. Microencapsulation yield was observed to be approximately 93.43%. In case of in vitro release behavior, the release rate of the capsules in the simulated gastric environment was feeble; however, the release rate in the simulated intestinal environment rapidly increased within 30 min, and nearly 70% of the core material was released within 120 min. The caramel flavor-supplemented beverage sample exhibited an exponential degradation in its flavor components. However, microcapsules containing flavor samples showed sustained flavor release compared to caramel flavor-filled samples under higher storage temperatures. In conclusion, the addition of coffee flavor microcapsules to coffee-containing milk beverages effectively extended the retention of the coffee flavor during the storage period.

Determination of Probiotic Abilities and Lactic Acid Content of Pediococcus acidilactici

Background:

Probiotics are living microorganisms that have a healthy influence on a host.

Objective:

The aim of this study was to isolate a probiotic Pediococcus acidilactici strain from newborn faeces and develop and optimize a selective high-performance liquid chromatography method for the determination and validation of its lactic acid content and also evaluate some probiotic characteristics.

Methods:

Isolated strains were identified by the API 50 CH system and 16S rDNA gene sequence analysis and tested for antibiotic susceptibility, bile salt tolerance, low pH resistance, proteolytic, haemolytic activity, as well as the production of bacteriocin, hydrogen peroxide, and lactic acid. Antimicrobial activity of selected strain against standard test microorganisms was determined by the spot lawn method and the quantitation of lactic acid was carried out by high-performance liquid chromatography on a Rezex ROA organic acid (300x7.8 mm) analytical column.

Results:

P. acidilactici M7 strain was evaluated as a potential probiotic due to its ability to survive at low pH values or in the presence of pepsin, pancreatin, and bile salts. The lactic acid amount of strain was found in the range between 5.59-5.94 mg mL-1 by HPLC. M7 strain was also found to be resistant to vancomycin, had no bacteriocin, and hydrogen peroxide production and was able to inhibit the growth of P. aeruginosa and E. faecalis by its lactic acid content.

Conclusion:

This study explains a simple, selective, and fully validated procedure for the determination of lactic acid from probiotic bacteria.

Physicochemical and sensory properties of milk supplemented with lactase microcapsules coated with enteric coating materials

In this paper, we report the physicochemical and sensory properties of milk supplemented with a powder of microencapsulated lactase. The core material was lactase (β-galactosidase), the primary coating material was medium-chain triglyceride (MCT), and the secondary (enteric) coating material was either hydroxypropyl methylcellulose phthalate (HPMCP) or shellac, comparing both against market milk as a control. The physicochemical properties of both types of microcapsules were analyzed, including the particle size, zeta potential, and in vitro release behavior. To survey the stability of the microcapsules in milk during storage, we studied the residual lactose content and pH. Furthermore, to determine the properties of milk supplemented with the microcapsules, changes in color and sensory properties were evaluated during storage. The particle sizes (volume-weighted mean; D[4,3]) of the microcapsules coated with HPMCP or shellac were 2,836 and 7,834 nm, respectively, and the zeta potential of the capsules coated with shellac was higher than the zeta potential of those coated with HPMCP. The pH levels of milk supplemented with the lactase microcapsules were similar to those of the control (unsupplemented market milk); however, for milk supplemented with HPMCP-coated microcapsules, the pH was slightly lower. The core material, lactase, was released from the microcapsules during 12-d storage, and 18.82 and 35.09% of lactose was hydrolyzed in the samples for HPMCP- and shellac-coated microcapsules, respectively. The sensory characteristics of milk containing microcapsules coated with HPMCP did not show significant differences from the control, in terms of sweetness or off-taste, until 8 d of storage. However, shellac-coated microcapsules showed significant difference in sweetness and off-taste at d 8 and 6 of storage, respectively. The color of milk containing HPMCP-coated microcapsules did not show a significant difference during storage. However, that containing shellac-coated microcapsules was somewhat higher in color values than others. In particular, it showed significance from 0 to 4 d storage in L* and C* values. In conclusion, a powder of lactase microcapsules coated with HPMCP can be suitable as a supplement for milk.

Evaluation of chitosan hydrochloride-alginate as enteric micro-probiotic-carrier with dual protective barriers

In this study, the cells-free and cells-loaded chitosan hydrochloride-alginate (CHC-Alg) microcapsules were firstly fabricated with polyelectrolyte complexes via an orifice-polymerization method. Scanning electron microscope images showed that the CHC-Alg microcapsules had a typical shell-core structure and the model probiotic cells (Bacillus licheniformis) were embedded in the core in cells-loaded microcapsules. The microcapsules prepared had good thermal stability and moisture property (3.89%). Cells survival and release studies showed that the number of probiotic cells released from the cells-loaded microcapsules (approx. 6.36logCFUml^-1) was 6.19logCFUml^-1 when they were performed in the simulated gastric fluid (SGF, pH 2.0) for 1h and subsequently in the simulated intestinal fluid (SIF, 0.3%) for 4h. The CHC-Alg microcapsules with favorable swelling performances were helpful to permeate the harsh acid to protect the cells in the SGF (pH 2.0). The CHC-Alg microcapsules effectively protected the model probiotic cells, which was attributed to the "dual protective barriers" of the shell-core structure, that is, the primary barrier of the Alg hydrogel layer formed with a compact polymer matrix and the secondary barrier of the PEC film formed on the surface. The microcapsules prepared could be used as an enteric micro-probiotic-carrier for designing potential probiotic delivery systems.

Enhancement of Lactobacillus reuteri KUB-AC5 survival in broiler gastrointestinal tract by microencapsulation with alginate-chitosan semi-interpenetrating polymer networks

AIMS

To evaluate an alginate-chitosan microcapsule for an intestinal probiotic delivery system for broilers.

METHODS AND RESULTS

Lactobacillus reuteri KUB-AC5 was successfully microencapsulated with alginate and chitosan mixtures using an emulsion cross-linking method with high microencapsulation efficiency. Scanning electron microscopy revealed a large number of the bacteria entrapped in the semi-interpenetrating network. The microcapsule effectively protected the cells against strong acids. The in vitro study showed that the 8 log CFU g(-1) was released at the jejunum and ileum. For the in vivo study, the number of probiotics was detected by a polymerase chain reaction-based random amplified polymorphic DNA technique. From provision of 10 log CFU, cell numbers of 5-8 log CFU were observed in the intestine.

CONCLUSIONS

The alginate-chitosan microcapsule can serve as a potential intestine-targeted probiotic delivery system.

SIGNIFICANCE AND IMPACTS OF THE STUDY

To the best of our knowledge, this is the first comparison study of the in vitro and in vivo gastrointestinal profiles of microencapsulated probiotics used as feed additives for broilers. This study reveals the similarities and differences of the in vitro and in vivo probiotic profiles and provides convincing evidence of the potential use of the alginate-chitosan microcapsule as a probiotic delivery system.

Effects of Lactobacillus plantarum immobilization in alginate coated with chitosan and gelatin on antibacterial activity

The present study aimed to investigate and evaluate the efficiency of immobilizing the Lactobacillus plantarum TN9 strain in alginate using chitosan and gelatin as coating materials, in terms of viability and antibacterial activity. The results indicate that maximum concentrations of L. plantarum TN9 strain were produced with 2% sodium alginate, 10(8)UFC/ml, and 1M calcium chloride. The viability and antibacterial activity of the L. plantarum TN9 cultures before and after immobilization in alginate, chitosan-coated alginate, and gelatin-coated alginate, were studied. The findings revealed that the viability of encapsulated L. plantarum could be preserved more than 5.8 log CFU/ml after 35 day of incubation at 4 °C, and no effects were observed when gelatin was used. The antibacterial activity of encapsulated L. plantarum TN9 against Gram-positive and Gram-negative pathogenic bacteria was enhanced in the presence of chitosan coating materials, and no activity was observed in the presence of gelatin. The effects of catalase and proteolytic enzymes on the culture supernatant of L. plantarum TN9 were also investigated, and the results suggested that the antibacterial activity observed was due to the production of organic acids. Taken together, the findings indicated that immobilization in chitosan enhanced the antibacterial activity of L. plantarum TN9 against several pathogenic bacteria. This encapsulated strain could be considered as a potential strong candidate for future application as an additive in the food and animal feed industries.

Microencapsulated probiotics using emulsification technique coupled with internal or external gelation process

Alginate-chitosan microcapsules containing probiotics (Yeast, Y235) were prepared by emulsification/external gelation and emulsification/internal gelation techniques respectively. The gel beads by external gelation showed asymmetrical structure, but those by internal gelation showed symmetrical structure in morphology. The cell viability was approximately 80% for these two techniques. However, during cell culture process, emulsification/internal gelation microcapsules showed higher cell growth and lower cell leakage. Moreover, the survival rate of entrapped low density cells with culture (ELDCwc) increased obviously than that directly entrapped high density cells (dEHDC) and free cells when keeping in simulated gastrointestinal conditions. It indicated the growth process of cells in microcapsule was important and beneficial to keep enough active probiotics under harmful environment stress. Therefore, the emulsification/internal gelation technique was the preferred method for application in food or biotechnological industries.

Microencapsulation of probiotics for gastrointestinal delivery

The administration of probiotic bacteria as nutraceuticals is an area that has rapidly expanded in recent years, with a global market worth $32.6 billion predicted by 2014. Many of the health promoting claims attributed to these bacteria are dependent on the cells being both viable and sufficiently numerous in the intestinal tract. The oral administration of most bacteria results in a large loss of viability associated with passage through the stomach, which is attributed to the high acid and bile salt concentrations present. This loss of viability effectively lowers the efficacy of the administered supplement. The formulation of these probiotics into microcapsules is an emerging method to reduce cell death during GI passage, as well as an opportunity to control release of these cells across the intestinal tract. The majority of this technology is based on the immobilization of bacteria into a polymer matrix, which retains its structure in the stomach before degrading and dissolving in the intestine, unlike the diffusion based unloading of most controlled release devices for small molecules. This review shall provide an overview of progress in this field as well as draw attention to areas where studies have fallen short. This will be followed by a discussion of emerging trends in the field, highlighting key areas in which further research is necessary.