Fabrication of sodium alginate gel beads encapsulating microcapsules viaTGase‐catalyzed crosslinking of gelatin in the outer aqueous phase of probiotics‐loaded W/O/W emulsions

Abstract BACKGROUND Probiotics are susceptible to both internal and external environments. METHODS Therefore, in this study, we developed two probiotic delivery systems comprising transglutaminase (TGase)‐crosslinked water‐in‐oil‐in‐water (W/O/W) emulsion microcapsules and sodium alginate gel beads to enhance gastrointestinal resistance and storage stability. RESULTS A W/O/W emulsion was fabricated via a two‐step emulsification process. The primary aqueous phase (W 1 ) contained Lactobacillus rhamnosus 76, while the oil phase (O) consisted of soybean oil. The double emulsion was formulated by dispersing varying mass fractions of W 1 /O emulsions into a 6% ( w/v ) gelatin solution. Microcapsules were formed through TGase‐catalyzed crosslinking of type A gelatin localized in the W 2 phase, creating a monolayer network structure. Gel beads were prepared by embedding the microcapsules in 2% sodium alginate, which significantly enhanced the cryoprotective capability of the encapsulated probiotics. Furthermore, both microcapsules and gel beads showed remarkable tolerance in simulated gastric fluid and enabled sustained probiotic release in the gastrointestinal conditions. During long‐term storage, they maintained viable cell counts > 10 6 CFU g −1 . Notably, gel beads exhibited better thermal stability than microcapsules under heat treatment. Conclusion This study presented a novel probiotic delivery strategy, offering tailored solutions for processing needs and advancing functional probiotic applications. © 2025 Society of Chemical Industry.