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

Large-scale dual-responsive ClO2 controlled-release film for strawberry preservation

Chlorine dioxide (ClO2) exhibits promising potential for the application in food preservation. However, the large-scale production of controlled-release ClO2 films faces challenges. The sodium chlorite microcapsules (Micro-SC) were successfully prepared in this study using polyvinyl alcohol (PVA) as the wall material through the spray drying method. Furthermore, A large-scale preparation of temperature and humidity dual-responsive ClO2 controlled-release films (Micro-SC@EVA) was achieved using melt extrusion. The film could release ClO2 triggered by water vapor for 36 days. The antibacterial effects were significantly enhanced with the increase of microcapsule ratio from 4 % to 8 %. The Micro-SC@EVA film reduced the total viable count and wight loss of strawberries, inhibits ethylene production, and extended the shelf life of by 150 % compared with the control group at 25 °C. The application evaluation results show that the novel approach for the large-scale preparation of ClO2 controlled-release film holds significant implications for food packaging.

Improving the physical stability of Lactobacillus plantarum LP90 during storage by mixing carboxymethylated dextran-whey protein conjugates and small-molecule sugars

To explore the effect of small-molecule sugars on the physical stability of microcapsules and enhance probiotic preservation, carboxymethylated dextran and whey protein conjugate (WP-CD5d) by Maillard reaction were used as the wall material. Trehalose, lactose, and sucrose were used as lyoprotectants to encapsulate Lactobacillus plantarum LP90 (LP90) during storage, forming microcapsules labeled as WP-CD5dH, WP-CD5dR, and WP-CD5dZ, respectively. WP-CD5dH and WP-CD5dR exhibited the highest viability after freeze-drying, with survival rates of 97.8 % ± 0.9 % and 98.5 % ± 0.5 % respectively. LP90 microcapsules exhibited strong resistance to simulated gastrointestinal fluid over 5 h. The Guggenheim-Anderson-de Boer (GAB) and Gordon-Taylor model showed that WP-CD5dH had the best reduction in water plasticization (k was 4.0). 1H NMR spectra confirmed that WP-CD5dH exhibited the lowest molecular mobility. Furthermore, the storage experiment showed that WP-CD5dH provided the best protection for LP90 at 11 % RH, with a K value of 0.021. These results suggest that the probiotic mechanism of small-molecule sugars involves forming intermolecular forces with WP-CD5d, which helps to maintain the glassy state.

Dual-action microparticles for ulcerative colitis: Cellulose nanofibers-enhanced delivery of 5-ASA and probiotics

Ulcerative colitis (UC) is a chronic inflammatory bowel disease initially treated with mesalazine (5-ASA). However, its effectiveness is limited by rapid absorption, low colonic concentration, and exacerbation of dysbiosis. Probiotics can mitigate dysbiosis if they survive the acidic conditions of the stomach. In this study, colon-specific microparticles (MPs) based on RS/P and reinforced with cellulose nanofibers (CNF) were used to co-encapsulate 5-ASA and L. rhamnosus. MPs prepared by spray-drying demonstrated a spherical shape, with sizes ranging from 1 to 10 μm, high encapsulation efficiency (up to 81.5 %), and maintenance of L. rhamnosus viability (5.74 log CFU/g of sample) even after 30 days of storage at 4 °C. Differential scanning calorimetry indicated a reduction in the melting peak of 5-ASA after microencapsulation, suggesting a decrease in its crystallinity. The samples also exhibited high mucoadhesivity, with the presence of CNF significantly increasing the speed of establishing interactions with mucin. In vitro release profiles showed lower release rates in acidic media, resulting in the majority of 5-ASA being released in intestinal and colonic media. These MPs represent a promising strategy for promoting specific release in the colon, minimizing side effects associated with conventional treatment, and potentially improving therapeutic efficacy in the context of UC.

The construction of a double-layer colon-targeted delivery system based on zein-shellac complex and gelatin-isomaltooligosaccharide Maillard product: In vitro and in vivo evaluation

In this study, we developed a double-layer colon-targeted microcapsule. It used the Maillard product of gelatin-isomaltooligosaccharide (GI180) and zein-shellac complex (ZS) as bio-based materials, plant extracts (MPL) and Lactobacillus plantarum JJBYG12 (JJBYG12) were co-encapsulated, endowing them with strong resistance to harsh environments and precise intestinal adhesion and targeting ability. The research results indicated that ZS11 exhibits hydrogen bonding and electrostatic interactions. The encapsulation efficiencies of ZS11 for JJBYG12 and for polysaccharides, polyphenols, and flavonoids in MPL were 88.03 %, 73.40 %, 77.90 %, and 70.87 %, respectively. SEM and CLSM images showed that ZS11 has a dense double-layer structure. Simulation of in vitro gastrointestinal digestion showed that ZS11 can achieve sustained release, with a live bacterial count of 8.05 ± 0.004 Log CFU/mL reaching the colon. The SEM and fluorescence images at different stages of in vitro digestion also demonstrated the strong protective ability of ZS11. Studies conducted in mice had shown that ZS11 can successfully pass through the gastric stage and release probiotics in the distal ileum, cecum, and proximal colon (target intestinal segment). Finally, ZS11 had good storage stability and thermal stability. In summary, this study demonstrated the potential of dual-layer colon-targeted microcapsules for the co-delivery plant extracts and probiotics, providing ideas for developing new delivery systems with targeted therapeutic effects.

Shellac-based materials: Structures, properties, and applications

Shellac stands out among natural polymers as the sole animal-derived resin, boasting a complex polyester composition comprising polyhydroxy long-chain fatty acids and sesquiterpene acids. Its unique attributes include biocompatibility, non-toxicity, distinctive amphiphilicity, superb film-forming and adhesive properties, excellent dielectric properties, rapid drying, and solubility in alkaline solutions while resisting acidic ones. These exceptional qualities have propelled shellac beyond its traditional role as a varnish and decorative material, positioning it as a viable option for diverse applications such as food packaging, pharmaceutical formulations, electronic devices, fiber dyeing, and wood restoration. Furthermore, shellac serves as a crucial carbon source for graphene materials. This review comprehensively explores shellac's contributions to prolonging food shelf life, enhancing the carbon sourcing of graphene materials, facilitating the delivery of active substances, boosting the performance of organic field-effect transistors, enabling environmentally friendly textile dyeing, and providing protective coatings for wood. Additionally, it delves into the current limitations and future directions of shellac's applications. By disseminating this knowledge, we aim to deepen researchers' comprehension of shellac and inspire further exploration, thereby fostering sustainable advancements across various industries.

Design of probiotic delivery systems and their therapeutic effects on targeted tissues

The microbiota at different sites in the body is closely related to disease. The intake of probiotics is an effective strategy to alleviate diseases and be adjuvant in their treatment. However, probiotics may suffer from harsh environments and colonization resistance, making it difficult to maintain a sufficient number of live probiotics to reach the target sites and exert their original probiotic effects. Encapsulation of probiotics is an effective strategy. Therefore, probiotic delivery systems, as effective methods, have been continuously developed and innovated to ensure that probiotics are effectively delivered to the targeted site. In this review, initially, the design of probiotic delivery systems is reviewed from four aspects: probiotic characteristics, processing technologies, cell-derived wall materials, and interactions between wall materials. Subsequently, the review focuses on the effects of probiotic delivery systems that target four main microbial colonization sites: the oral cavity, skin, intestine, and vagina, as well as disease sites such as tumors. Finally, this review also discusses the safety concerns of probiotic delivery systems in the treatment of disease and the challenges and limitations of implementing this method in clinical studies. It is necessary to conduct more clinical studies to evaluate the effectiveness of different probiotic delivery systems in the treatment of diseases.

A protectant for Lactobacillus rhamnosus based on whey protein isolate and isomalt: Stress resistance and underlying mechanisms

Probiotics are exposed to a variety of abiotic and biotic stresses during food fermentation and production, such as acidity, heat, osmolality, and oxidation, which affect their metabolic activity and efficiency. Therefore, it is essential to develop new protective agents to maintain the activity and stability of probiotics. This study introduces a new protectant, spray-dried whey protein isolate (WPI) and isomaltose (ISO). We evaluated the effects of four WPI-ISO ratios (1:0, 2:1, 1:1, 1:2) on the physical properties, including moisture content, water activity (aw), wettability, and glass transition temperature. In addition, we evaluated the environmental tolerance of Lactobacillus rhamnosus to different WPI-ISO ratios under thermal, storage, and simulated gastrointestinal conditions. The results showed that the moisture content (< 7 %) and water activity (< 0.3) of the protectant and probiotic powders met storage stability requirements. The moisture content, water activity, wettability index (WI), and glass transition temperature decreased significantly with the addition of isomalt, thereby improving the pressure resistance of L. rhamnosus through the synergistic effect of WPI and ISO. The WPI-ISO protectant not only improved the environmental tolerance and wettability of probiotics by reducing the moisture content and water activity but also significantly improved the survival rate of L. rhamnosus under various stress conditions such as high temperature and gastrointestinal environment. L. rhamnosus maintains good activity with a viable bacterial count of over 9 lg CFU/g after 90 days of storage, demonstrating effective protection against the environment stress. This study provides a promising new strategy to improve the stability of probiotics in the food industry.

Current Challenges in Microcapsule Designs and Microencapsulation Processes: A Review

Microencapsulation is an advanced methodology for the protection, preservation, and/or delivery of active materials in a wide range of industrial sectors, such as pharmaceuticals, cosmetics, fragrances, paints, coatings, detergents, food products, and agrochemicals. Polymeric materials have been extensively used as microcapsule shells to provide appropriate barrier properties to achieve controlled release of the encapsulated active ingredient. However, significant limitations are associated with such capsules, including undesired leaching and the nonbiodegradable nature of the typically used polymers. In addition, the energy cost of manufacturing microcapsules is an important factor to be considered when designing microcapsule systems and the corresponding production processes. Recent factors linked to UN sustainability goals are modifying how such microencapsulation systems should be designed in pursuit of "ideal" microcapsules that are efficient, safe, cost-effective and environmentally friendly. This review provides an overview of advances in microencapsulation, with emphasis on sustainable microcapsule designs. The key evaluation techniques to assess the biodegradability of microcapsules, in compliance with recently evolving European Union requirements, are also described. Moreover, the most common methodologies for the fabrication of microcapsules are presented within the framework of their energy demand. Recent promising microcapsule designs are also highlighted for their suitability toward meeting current design requirements and stringent regulations, tackling the ongoing challenges, limitations, and opportunities.

Screening the Protective Agents Able to Improve the Survival of Lactic Acid Bacteria Strains Subjected to Spray Drying Using Several Key Enzymes Responsible for Carbohydrate Utilization

The aim of this study was to identify the most effective protectants for enhancing the viability of specific lactic acid bacteria (LAB) strains (Lactobacillus delbrueckii subsp. bulgaricus CICC 6097, Lactiplantibacillus plantarum CICC 21839, Lactobacillus acidophilus NCFM) by assessing their enzymatic activity when exposed to spray drying (inlet/outlet temperature: 135 °C/90 °C). Firstly, it was found that the live cell counts of the selected LAB cells from the 10% (w/v) recovered skim milk (RSM) group remained above 107 CFU/g after spray drying. Among all the three groups (1% w/v RSM group, 10% w/v RSM group, and control group), the two enzymes pyruvate kinase (PK) and lactate dehydrogenase (LDH) were more sensitive to spray drying than hexokinase (HK) and β-galactosidase (β-GAL). Next, transcriptome data of Lb. acidophilus NCFM showed that 10% (w/v) RSM improved the down-regulated expressions of genes encoding PK (pyk) and LDH (ldh) after spray drying compared to 1% (w/v) RSM. Finally, four composite protectants were created, each consisting of 10% (w/v) RSM plus a different additive-sodium glutamate (CP-A group), sucrose (CP-B group), trehalose (CP-C group), or a combination of sodium glutamate, sucrose, and trehalose (CP-D group)-to encapsulate Lb. acidophilus NCFM. It was observed that the viable counts of strain NCFM (8.56 log CFU/g) and enzymatic activity of PK and LDH in the CP-D group were best preserved compared to the other three groups. Therefore, our study suggested that measuring the LDH and PK activity could be used as a promising tool to screen the effective spray-dried protective agent for LAB cells.

Ultrasonic pre-treatment to enhance drying of potentially probiotic guava (Psidium guajava): Impact on drying kinetics, Lacticaseibacillus rhamnosus GG viability, and functional quality

This study aimed to evaluate the effects of ultrasound (US) on the drying acceleration of potentially probiotic guava, including its impact on drying kinetics, probiotic (Lacticaseibacillus rhamnosus GG) viability, and functional quality of the product during drying. To perform US pre-treatments, one group of samples were first pre-treated by US (38 W/L, 25 kHz) for 15 and 30 min and then immersed in the probiotic solution for 15 or 30 min, and another group of samples were submerged in the probiotic solution simultaneously applying US (US-assisted) for 15 and 30 min. After pre-treatments, the samples were convectively dried at 60 °C. Based on the results, all US pre-treatments improved the drying rate (up to 59%) and reduced the drying time (up to 31%) to reach 25% moisture compared to non-sonicated samples. The reduction in drying time (from ∼6 h to ∼4 h for US pre-treated samples) was crucial for maintaining the probiotic viability in the dehydrated guavas. These samples showed counts of 6.15 to 7.00 CFU∙g-1 after 4 h, while the control samples reached counts of 4.17 to 4.45 CFU∙g-1 after 6 h. US pre-treatment did not affect the color parameters of the samples before drying (p > 0.05). The functional compounds were reduced during drying (p < 0.05), however, all US pre-treated samples had lower reductions in vitamin C content (up to 20%), phenolic compounds (up to 41%) and antioxidant capacity (up to 47%) compared to control samples (up to 52%, 81% and 61%, respectively). Therefore, US pre-treatment (highlighting the US-assisted probiotic incorporation for 30 min) reduced the drying time for guava slices and minimized the thermal impact on probiotic viability and functional compounds, being a strategy to produce potentially probiotic dehydrated guava.

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.

Improved Viability of Probiotics via Microencapsulation in Whey-Protein-Isolate-Octenyl-Succinic-Anhydride-Starch-Complex Coacervates

The aim of this study was to microencapsulate probiotic bacteria (Lactobacillus acidophilus 11073) using whey-protein-isolate (WPI)-octenyl-succinic-anhydride-starch (OSA-starch)-complex coacervates and to investigate the effects on probiotic bacterial viability during spray drying, simulated gastrointestinal digestion, thermal treatment and long-term storage. The optimum mixing ratio and pH for the preparation of WPI-OSA-starch-complex coacervates were determined to be 2:1 and 4.0, respectively. The combination of WPI and OSA starch under these conditions produced microcapsules with smoother surfaces and more compact structures than WPI-OSA starch alone, due to the electrostatic attraction between WPI and OSA starch. As a result, WPI-OSA-starch microcapsules showed significantly (p < 0.05) higher viability (95.94 ± 1.64%) after spray drying and significantly (p < 0.05) better protection during simulated gastrointestinal digestion, heating (65 °C/30 min and 75 °C/10 min) and storage (4/25 °C for 12 weeks) than WPI-OSA-starch microcapsules. These results demonstrated that WPI-OSA-starch-complex coacervates have excellent potential as a novel wall material for probiotic microencapsulation.

The encapsulation strategy to improve the survival of probiotics for food application: From rough multicellular to single-cell surface engineering and microbial mediation

The application of probiotics is limited by the loss of survival due to food processing, storage, and gastrointestinal tract. Encapsulation is a key technology for overcoming these challenges. The review focuses on the latest progress in probiotic encapsulation since 2020, especially precision engineering on microbial surfaces and microbial-mediated role. Currently, the encapsulation materials include polysaccharides and proteins, followed by lipids, which is a traditional mainstream trend, while novel plant extracts and polyphenols are on the rise. Other natural materials and processing by-products are also involved. The encapsulation types are divided into rough multicellular encapsulation, precise single-cell encapsulation, and microbial-mediated encapsulation. Recent emerging techniques include cryomilling, 3D printing, spray-drying with a three-fluid coaxial nozzle, and microfluidic. Encapsulated probiotics applied in food is an upward trend in which "classic probiotic foods" (yogurt, cheese, butter, chocolate, etc.) are dominated, supplemented by "novel probiotic foods" (tea, peanut butter, and various dry-based foods). Future efforts mainly include the effect of novel encapsulation materials on probiotics in the gut, encapsulation strategy oriented by microbial enthusiasm and precise encapsulation, development of novel techniques that consider both cost and efficiency, and co-encapsulation of multiple strains. In conclusion, encapsulation provides a strong impetus for the food application of probiotics.