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

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.