Soft matter-engineered pH-responsive hydrogels for encapsulation, protection, and controlled intestinal release of...

pH-responsive hydrogel microcapsules were fabricated from pea protein isolate (PPI) and low-methoxyl pectin (LMP) for the targeted intestinal delivery of Lacticaseibacillus paracasei YWC-01, a probiotic capable of biodegrading uric acid precursors in vitro. Microgels with interpenetrating networks were fabricated via emulsion-templating: probiotics, PPI, LMP, CaCl₂, and glucono-δ-lactone were emulsified in oil and crosslinked by Ca²⁺. Optimized formulation (5% w/v PPI) achieved 94.80% encapsulation efficiency. Microgel size (43-63 μm) was controlled by adjusting Span 80 surfactant concentration. FTIR confirmed probiotic encapsulation via noncovalent interactions, while TEM revealed bacterial clustering within hydrogel voids. In vitro digestion demonstrated exceptional protection: encapsulated probiotics maintained >9 log₁₀ CFU/g viability (<0.4 log reduction), versus 3.2 log reduction in free cells. Metabolomics indicated encapsulation preserved bioactivity and significantly upregulated functional metabolites potentially enhancing gut microbiota modulation and anti-inflammatory effects. This work establishes an effective oral delivery platform that significantly enhances probiotic gastrointestinal survival and enables targeted release.