Microencapsulation of Bifidobacterium animalis subsp . lactis INL1 using whey proteins and dextrans conjugates as wall materials

Advances in protein-based microcapsules and their applications: A review

Due to their excellent emulsification, biocompatibility, and biological activity, proteins are widely used as microcapsule wall materials for encapsulating drugs, natural bioactive substances, essential oils, probiotics, etc. In this review, we summarize the protein-based microcapsules, discussing the types of proteins utilized in microcapsule wall materials, the preparation process, and the main factors that influence their properties. Additionally, we conclude with examples of the vital role of protein-based microcapsules in advancing the food industry from primary processing to deep processing and their potential applications in the biomedical, chemical, and textile industries. However, the low stability and controllability of protein wall materials lead to degraded performance and quality of microcapsules. Protein complexes with polysaccharides or modifications to proteins are often used to improve the thermal instability, pH sensitivity, encapsulation efficiency and antioxidant capacity of microcapsules. In addition, factors such as wall material composition, wall material ratio, the ratio of core to wall material, pH, and preparation method all play critical roles in the preparation and performance of microcapsules. The application area and scope of protein-based microcapsules can be further expanded by optimizing the preparation process and studying the microcapsule release mechanism and control strategy.

Design of gum Arabic/gelatin composite microcapsules and their cosmetic applications in encapsulating tea tree essential oil

Microencapsulation has been widely used to protect essential oils, facilitating their application in cosmetics. In this study, gelatin, gum arabic and n-butyl cyanoacrylate were used as wall materials, and composite microcapsules of tea tree essential oil (TTO) were prepared using a combination of composite coagulation and in situ polymerization methods. When the ratio of gelatin to gum arabic is 1 : 1, the ratio of TTO to n-butyl cyanoacrylate is 4 : 1, the curing time is 10 h, and the encapsulation efficiency (EE) under these conditions is 73.61%. Morphological observation showed that the composite capsule was a micron-sized spherical particle with an average particle size of 10.51 μm, and Fourier transform infrared spectroscopy (FT-IR) confirmed a complex coagulation reaction between gelatin and gum arabic, and the disappearance of the n-butyl cyanoacrylate peak indicated that the film was formed in a condensation layer. The thermogravimetric analysis (TGA) results showed that the composite capsule greatly improved the thermal stability of TTO. Rheological testing showed that the viscosity and viscoelasticity of the surface composite capsules have been improved. In addition, the composite capsule showed good stability in the osmotic environment and has good sustained-release performance and antioxidant capacity in the average human skin environment.

Chitosan-glucose derivative as effective wall material for probiotic yeasts microencapsulation

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.

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

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

Application of soy protein isolate-xylose conjugates for improving the viability and stability of probiotics microencapsulated by spray drying

BACKGROUND

Production and consumption of probiotics need to meet many adverse stresses, which can reduce their health-promoting effects on humans. Microencapsulation is an effective technique to improve the biological activity of probiotics and wall materials are also required during encapsulation. Application of Maillard reaction products (MRPs) in probiotic delivery is increasing.

RESULTS

This work aims to study the effects of soy protein isolate (SPI)-xylose conjugates heated at different times on the viability and stability of probiotics. SPI-xylose MRPs formed after heat treatment based on changes in the browning intensity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy. After heat treatment, α-helix and β-sheet contents of SPI-xylose mixture shifted from 11.3% and 31.3% to 6.4-11.0% and 31.0-36.9%, respectively, and the thermal stability slightly changed. During spray drying, except for MRP240@LAB, probiotic viability was higher in the MRP-based probiotic microcapsules (21.36-25.31%) than in Mix0@LAB (20.17%). MRP-based probiotic microcapsules had smaller particle sizes (431.1-1243.0 nm vs. 7165.0 nm) and greater intestinal digestion tolerance than Mix0@LAB. Moreover, the MRP-based probiotic microcapsules showed better storability than Mix0@LAB and adequate growth and metabolism capacity.

CONCLUSION

SPI-xylose Maillard reaction products are a promising wall material for probiotics microencapsulation, which can improve bacterial survivability during spray drying and enhance bacterial gastrointestinal digestion resistance. This study sheds light on preparing probiotic microcapsules with superior properties by spray drying. © 2023 Society of Chemical Industry.

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.

The dual effect of shellac on survival of spray-dried Lactobacillus rhamnosus GG microcapsules

Heat shock and hygroscopicity are two main factors that resulted in low viability of probiotics in spray-dried microcapsules during storage. Hydrophobic polyester shellac was combined with whey protein isolate (WPI) to solve this problem. The results suggested that although the survival rate after drying decreased from 20.63% to 0.01% with increased shellac to WPI ratio, the 1:1 shellac-WPI provided the best protection among all samples during storage. The consistence between moisture-adsorption-isotherm and bacterial inactivation constants confirmed the moisture barrier effect of shellac under moderate humidity. Single-droplet drying and differential scanning calorimeter revealed that shellac addition reduced the drying rate and glass transition temperature of microcapsules, which in turn decreased the membrane integrity and growth capability of the probiotics after drying. This study revealed the dual effect of hydrophobic material on instant and long-term survival of spray-dried probiotic microcapsules, which provided new sight to the design of composite wall materials.

Bifidobacterium spp. as functional foods: A review of current status, challenges, and strategies

Members of Bifidobacterium are among the first microbes to colonize the human intestine naturally, their abundance and diversity in the colon are closely related to host health. Recently, the gut microbiota has been gradually proven to be crucial mediators of various metabolic processes between the external environment and the host. Therefore, the health-promoting benefits of Bifidobacterium spp. and their applications in food have gradually been widely concerned. The main purpose of this review is to comprehensively introduce general features, colonization methods, and safety of Bifidobacterium spp. in the human gut, highlighting its health benefits and industrial applications. On this basis, the existing limitations and scope for future research are also discussed. Bifidobacteria have beneficial effects on the host's digestive system, immune system, and nervous system. However, the first prerequisite for functioning is to have enough live bacteria before consumption and successfully colonize the colon after ingestion. At present, strain breeding, optimization (e.g., selecting acid and bile resistant strains, adaptive evolution, high cell density culture), and external protection technology (e.g., microencapsulation and protectants) are the main strategies to address these challenges in food application.

Co-microencapsulation: a promising multi-approach technique for enhancement of functional properties

Co-microencapsulation is a growing technique in the food industry because it is a technique that, under the same fundamentals of microencapsulation, allows the generation of microcapsules with a longer shelf life, using a smaller number of encapsulating materials and a smaller amount of active compounds, while having a greater beneficial activity. This responds to consumer demand for higher quality foods that limit the use of ingredients with low nutritional content and provide beneficial health effects, such as probiotics, prebiotics, vitamins, fatty acids, and compounds with antioxidant activity. The combination of two or more active compounds that achieve a synergy between them and between the encapsulating materials offers an advantage over the well-known microencapsulation. Among the main active compounds used in this process are probiotics, prebiotics, fatty acids, and polyphenols, the main combination being that of probiotics with one of the other active compounds that enhances their benefits. The present review discusses the advantages and disadvantages of the different encapsulating materials and techniques used to obtain co-microencapsulants, where the main result is a higher survival of probiotics, higher stability of the active compounds and a more controlled release, which can lead to the generation of new foods, food supplements, or therapeutic foods for the treatment of common ailments.

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.

Novel Antioxidative Wall Materials for Lactobacillus casei Microencapsulation via the Maillard Reaction between the Soy Protein Isolate and Prebiotic Oligosaccharides

In this study, three kinds of Maillard reaction products (MRPs) have been, for the first time, successfully prepared by conjugating soy protein isolate (SPI) with isomaltooligosaccharide, xylooligosaccharide, or galactooligosaccharide at 80 °C for 30 or 60 min and applied for the construction of Lactobacillus casei (L. casei) microcapsules. The results showed that MRPs exhibited enhanced antioxidative activities compared with their physically mixed counterparts. The digested MRPs displayed excellent resistance to pathogenic bacteria and promoted the growth of L. casei. Moreover, MRP-encapsulated L. casei showed a higher survival rate than free L. casei under tested adverse conditions including heat treatment, storage, and mechanical forces. Under simulated digestion conditions, the viability of L. casei decreased from 8.8 log cfu/mL to 1.6 log cfu/mL, while that of MRP-encapsulated L. casei was maintained at 7.4 log cfu/mL. Thus, MRP-based SPI-oligosaccharide conjugates exhibited great potential for microencapsulation of probiotics.

Utilization of diverse protein sources for the development of protein-based nanostructures as bioactive carrier systems: A review of recent research findings (2010-2021)

Consumer awareness of the relationship between health and nutrition has caused a substantial increase in the demand for nutraceuticals and functional foods containing bioactive compounds (BACs) with potential health benefits. However, the direct incorporation of many BACs into commercial food and beverage products is challenging because of their poor matrix compatibility, chemical instability, low bioavailability, or adverse impact on food quality. Advanced encapsulation technologies are therefore being employed to overcome these problems. In this article, we focus on the utilization of plant and animal derived proteins to fabricate micro and nano-particles that can be used for the oral delivery of BACs such as omega-3 oils, vitamins and nutraceuticals. This review comprehensively discusses different methods being implemented for fabrications of protein-based delivery vehicles, types of proteins used, and their compatibility for the purpose. Finally, some of the challenges and limitations of different protein matrices for encapsulation of BACs are deliberated upon. Various approaches have been developed for the fabrication of protein-based microparticles and nanoparticles, including injection-gelation, controlled denaturation, and antisolvent precipitation methods. These methods can be used to construct particle-based delivery systems with different compositions, sizes, surface hydrophobicity, and electrical characteristics, thereby enabling them to be used in a wide range of applications.

Preparation and Characterization of Ginger Essential Oil Microcapsule Composite Films

New food packaging has shown research significance in the face of increasing demand for high-quality foods and growing attention paid to food safety. In this study, ginger essential oil microcapsule composite films were prepared by combining microcapsules prepared by a complex coacervation method with gelatin films, and the mechanical properties and active functions of the composite films were analyzed. Fourier-transform infrared spectroscopy and differential scanning calorimetry confirmed the successful encapsulation of ginger essential oil. The scanning electron microscopy of the composite films showed the microcapsules and gelatin film matrix were highly compatible. During the entire storage period, the antioxidant capacity of the ginger essential oil microcapsule films weakened more slowly than ginger essential oil microcapsules and could be maintained at a relatively high level for a long time. The microcapsule films had excellent inhibitory effects on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. Therefore, the direct addition of microcapsules to a film matrix can broaden the application range of microcapsules and increase the duration of the release of active ingredients. Ginger essential oil microcapsule films are potential biodegradable food packaging films with long-lasting activity.

Maillard conjugates of whey protein isolate-xylooligosaccharides for the microencapsulation of Lactobacillus rhamnosus: protective effects and stability during spray drying, storage and gastrointestinal digestion

The Maillard reaction products (MRPs) of whey protein isolate (WPI) and xylooligosaccharides (XOS) were prepared by a moist heat method for use as protectants to encapsulate Lactobacillus rhamnosus via spray drying. The protective effects of MRPs on bacterial cells during drying, storage, and in vitro digestion were explored. FTIR results indicated that MRPs were successfully prepared. All MRPs showed good thermo-protective effect on the bacteria, and the survival ratio achieved with 1 : 2 XOS-WPI as a wall material reached 99.83 ± 8.44%, which was around 2 times as high as that of the WPI wall material and 1.5 times as high as that of the 1 : 2 XOS-WPI mixture. The dried lactobacilli showed similar growth curves to the fresh culture. After 10 weeks of storage at 4 °C, the decrease in the bacterial activity was less than 1 log CFU g-1 for all types of microcapsules, while the microcapsules composed of all MRPs had better storage stability. MRPs improved the stability of microcapsules during in vitro digestion. The number of viable bacteria in 1 : 2 XOS-WPI MRPs microcapsules was maintained at 4.09 ± 0.59 × 109 CFU g-1 after simulated gastrointestinal digestion for 4 hours, which only decreased by 0.20 log CFU g-1.

In vitro digestion of polysaccharides: InfoGest protocol and use of small intestinal extract from rat

Starch, dextran, pectin and modified citrus pectin were subjected to intestinal digestion following InfoGest protocol and a rat small intestine extract (RSIE) treatment. Gastric stage did not show any modification in the structure of the carbohydrates, except for modified pectin. Regarding intestinal phases, starch was hydrolyzed by different ways, resulting in a complementary behavior between InfoGest and RSIE. Contrarily, digestion of dextran was only observed using RSIE. Similar situation occurred in the case of pectins with RSIE, obtaining a partial hydrolysis, especially in the modified citrus pectin. However, citrus pectin was the less prone to hydrolysis by enzymes. The results demonstrated that InfoGest method underestimates the significance of the carbohydrates hydrolysis at the small intestine, thus indicating that RSIE is a very reliable and useful method for a more realistic study of polysaccharides digestion.

Inclusion of Probiotics into Fermented Buffalo (Bubalus bubalis) Milk: An Overview of Challenges and Opportunities

Buffalo-milk-based dairy products provide various health benefits to humans since buffalo milk serves as a rich source of protein, fat, lactose, calcium, iron, phosphorus, vitamin A and natural antioxidants. Dairy products such as Meekiri, Dadih, Dadi and Lassie, which are derived from Artisanal fermentation of buffalo milk, have been consumed for many years. Probiotic potentials of indigenous microflora in fermented buffalo milk have been well documented. Incorporation of certain probiotics into the buffalo-milk-based dairy products conferred vital health benefits to the consumers, although is not a common practice. However, several challenges are associated with incorporating probiotics into buffalo-milk-based dairy products. The viability of probiotic bacteria can be reduced due to processing and environmental stress during storage. Further, incompatibility of probiotics with traditional starter cultures and high acidity of fermented dairy products may lead to poor viability of probiotics. The weak acidifying performance of probiotics may affect the organoleptic quality of fermented dairy products. Besides these challenges, several innovative technologies such as the use of microencapsulated probiotics, ultrasonication, the inclusion of prebiotics, use of appropriate packaging and optimal storage conditions have been reported, promising stability and viability of probiotics in buffalo-milk-based fermented dairy products.

Carboxymethylation of (1 → 6)-α-dextran from Leuconostoc spp.: Effects on microstructural, thermal and antioxidant properties

The carboxymethylated (1 → 6)-α-dextran (CM-dex) was synthesized by introducing carboxymethyl groups at different degrees of substitution (DS). The resulting dex1-1, dex2-1, dex3-1, and dex4-1 products had degrees of substitution of 0.57, 0.78, 1.13, and 1.25, respectively. The dex3-1 showed the highest glass transition temperature (T_g) of 215.96 °C, whereas T_g of pure dextran was 149.83 °C. TGA results indicated that the residual loss was reduced along with the increase of DS in the high-temperature region (450-600 °C). Besides, the CM-dex had stronger scavenging capacity against OH radicals but lower scavenging capacity for DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals compared to that of pure dextran. The carboxymethylation of (1 → 6)-α-dextran will extend the applications for modified dextran.

Co-Microencapsulation of Anthocyanins from Black Currant Extract and Lactic Acid Bacteria in Biopolymeric Matrices

Anthocyanins from black currant extract and lactic acid bacteria were co-microencapsulated using a gastro-intestinal-resistant biocomposite of whey protein isolate, inulin, and chitosan, with an encapsulation efficiency of 95.46% ± 1.30% and 87.38% ± 0.48%, respectively. The applied freeze-drying allowed a dark purple stable powder to be obtained, with a satisfactory content of phytochemicals and 11 log colony forming units (CFU)/g dry weight of powder (DW). Confocal laser microscopy displayed a complex system, with several large formations and smaller aggregates inside, consisting of biologically active compounds, lactic acid bacteria cells, and biopolymers. The powder showed good storage stability, with no significant changes in phytochemicals and viable cells over 3 months. An antioxidant activity of 63.64 ± 0.75 mMol Trolox/g DW and an inhibitory effect on α-amylase and α-glucosidase of 87.10% ± 2.08% and 36.96% ± 3.98%, respectively, highlighted the potential biological activities of the co-microencapsulated powder. Significantly, the in vitro digestibility profile showed remarkable protection in the gastric environment, with controlled release in the intestinal simulated environment. The powder was tested by addition into a complex food matrix (yogurt), and the results showed satisfactory stability of biologically active compounds when stored for 21 d at 4 °C. The obtained results confirm the important role of microencapsulation in ensuring a high degree of protection, thus allowing new approaches in developing food ingredients and nutraceuticals, with enhanced functionalities.

Stability of bifidobacteria entrapped in goat's whey freeze concentrate and inulin as wall materials and powder properties

Goat's whey was submitted to two cycles of block freeze concentration process, resulting in concentrate 1 and concentrate 2. Concentrate 1 was added with 5 g of inulin and both concentrates were inoculated with Bifidobacterium animalis ssp. lactis BB-12, the concentrates were then denoted as feed solutions 1 and 2, respectively. Feed solutions were spray-dried, resulting in powder 1 and 2. The stability of the bifidobacteria entrapped within the powders was evaluated for both spray-dried powders stored at 4 °C and 25 °C for 60 days. The spray-dried powders were also evaluated in relation to their physical and thermal properties. It was noted that Bifidobacteria displayed increased stability at refrigeration temperature. Analysis of physical properties indicated that the addition of inulin resulted in increased water solubility. However, both spray-dried powders displayed less flowability, as well as a yellow-greenish color. By evaluating the spray-dried powders thermal properties, it was possible to confirm that goat whey concentrates behave as excellent wall materials.

The complete genome sequence of Bifidobacterium animalis subsp. lactis 01 and its integral components of antioxidant defense system

The strain Bifidobacterium animalis 01, isolated from centenarians, showed promising antioxidant potential in our previous studies. In this study, the genome information on strain 01 and the important antioxidant components are presented. The complete genome comprises a single circular chromosome (1,931,632 bp; 60.49% G + C content) with 1569 coding DNA sequences, 52 tRNA, and 9 rRNA operons. Based on phylogenomic analyses, strain 01 was designated as B. animalis subsp. lactis 01. The genomic analysis reveals that at least eight protein-coding genes are antioxidant-related genes. The conditions for simulating the oxidative stress have been determined. The results of quantitative reverse transcription PCR further demonstrated that the genes encoding the thioredoxin system (ahpC, ahpF, bcp, trxB, trxA, nrdH, and msrAB) and non-enzyme factors of the divalent cation transporter gene (mntH) were upregulated under the H₂O₂ challenge, indicating that the eight genes were effective components of the antioxidant system. The results of this study could benefit for understanding the antioxidant mechanism of B. animalis 01 and future utilization of it as a potential antioxidant agent.