Preparation of polyvinyl alcohol/pullulan nanofibers and Eudragit® S100/polyvinyl alcohol/pullulan core-shell nanofibers for enhanced probiotic storage and oral viability

Probiotics, which play a crucial role in regulating intestinal homeostasis and maintaining host health, face significant challenges in maintaining their survival rate after processing, storage, and oral administration, posing a substantial hurdle in probiotic use. In this study, electrospinning technology was employed to prepare polyvinyl alcohol (PVA)/Pullulan (PUL) nanofibers and Eudragit® S100 (ES100)/PVA/PUL core-shell nanofibers. The effects of different PVA, PUL, and ES100 solution concentrations, applied voltage, collector distance, and feed rate on the morphology and diameter of nanofibers were investigated by scanning electron microscopy. The fibers were characterized using fourier transform infrared spectroscopy, X-ray diffraction, and thermal analysis. Additionally, the storage stability and resistance to gastrointestinal stress of the nanofibers loaded with Lactiplantibacillus plantarum KLDS1.0386 were investigated. The results indicate that the prepared PVA/PUL nanofibers and ES100/PVA/PUL core-shell nanofibers exhibit smooth surfaces, uniform diameters, and excellent thermal stability. Compared with free L. plantarum KLDS1.0386, the survival rate of PVA/PUL nanofiber-encapsulated bacteria increased by 25.07% after 21 days of storage at 4 °C and by 33.21% at 25 °C, respectively. Experiments simulating gastrointestinal digestion showed that the survival rates of PVA/PUL nanofibers and ES100/PVA/PUL nanofiber-coated L. plantarum KLDS1.0386 were 9.11% and 15.73% higher in simulated gastric juice compared to free L. plantarum KLDS1.0386, respectively. Additionally, 13.15% and 13.92% higher in simulated intestinal fluid, respectively. The nanofibers prepared in this study can be used as delivery carriers for probiotics. They enhance the storage stability and improve the tolerance of probiotics to the harsh gastrointestinal environment.