Development of Sodium Alginate/Cellulose Nanofiber (SA/CNF)-Based Hydrogels for Enhancing Probiotic Stability

Probiotics can promote gut health, but their efficacy is often limited by low viability and metabolic activity in the gastrointestinal (GI) tract. This study aimed to develop protective hydrogels for encapsulating Lactiplantibacillus plantarum CJLP 133 using a composite matrix of sodium alginate (SA) and cellulose nanofibers (CNFs). L. plantarum CJLP 133-loaded hydrogel beads were fabricated via the ionic gelation technique using an optimized formulation of SA and CNF. Scanning electron microscopy revealed that CNF integration improved spherical morphology with reduced surface cracking. Fourier transform infrared spectroscopy confirmed the formation of intermolecular hydrogen bonds between SA and CNF. CNF integration also reduced gumminess and chewiness, resulting in a softer texture. The survival rate of L. plantarum CJLP 133 remained high following thermal exposure and freeze-drying. The in vitro GI delivery system demonstrated a protective swelling profile in stimulated gastric fluid and a targeted, highly efficient release profile in stimulated intestinal fluid. Finally, the 3% SA + 0.5% CNF hydrogel with L. plantarum CJLP 133 exhibited significant synbiotic effects, enhancing probiotic growth, intestinal adhesion, and butyrate and succinate production. These results suggest that the SA/CNF-based hydrogel is an effective delivery system that ensures the targeted release of probiotics within the GI tract.