Polysaccharide-based conjugate systems for probiotic encapsulation and colon - targeted release: A review

Oral probiotics face viability challenges during processing, storage, and gastrointestinal transit. This critical review provides a unified analytical framework for polysaccharide-based conjugated probiotic encapsulation, bridging synthesis chemistry, delivery mechanisms, and industrial feasibility. Covalent modification and network-forming routes, including Maillard glycation, chemical crosslinking, enzymatic crosslinking, radical-mediated grafting, and thiol-based functionalization, are compared with non-covalent assembly and energy-assisted processing in terms of network architecture, thermal resistance, and scalability. Colon-targeted release mechanisms, including pH-responsive swelling, enzymatic degradation, microbiota fermentation, and multi-stimuli architectures, are critically evaluated. Practical applicability in commercial matrices like yogurt, kefir, honey, and ice cream is discussed alongside processing and regulatory considerations. While conjugated matrices offer superior gastric protection and controllable release, critical gaps remain in release kinetics, long-term storage data, residual crosslinker safety, and strain-specific variability. Translational readiness requires integrating AI-driven predictive design, life cycle assessment, and standardized gastrointestinal simulation protocols.