Maize starch and β-cyclodextrin nanocarriers for encapsulation of Centella asiatica polyphenols: synthesis, physicochemical properties, and pH-responsive delivery

This study reports a novel dual-polysaccharide nanocarrier system based on maize starch (MS) and β-cyclodextrin (β-CD) for the pH-responsive oral delivery of Centella asiatica leaf polyphenols (CALE). Thus, this work reported a synergistic MS/β-CD composite nanoparticle system that integrates starch gel-network entrapment with cyclodextrin inclusion complexation to protect polyphenols. The results demonstrate that polymer at a 2:1 MS/β-CD formulation yielded highly uniform nanoparticles (166.990 ± 11.475 nm) with exceptionally high encapsulation efficiency (84.828 ± 0.50%) and loading capacity (16.349 ± 0.35%), outperforming starch-only systems. Spectroscopic and thermal analyses confirmed the formation of amorphous, hydrogen-bond-stabilized nanocomposites, providing enhanced resistance to heat, light, ionic strength, and storage-induced degradation. Importantly, the nanoparticles exhibited a distinct gastrointestinal pH-responsive behavior, suppressing polyphenol release under gastric conditions while enabling targeted intestinal release. Release kinetics followed Zero-order and Korsmeyer-Peppas models, indicating a diffusion- and matrix-relaxation-controlled delivery mechanism that enables sustained bioactive availability. This study demonstrates for the starch-cyclodextrin nanohybrids can function as food-grade, pH-responsive delivery systems for polyphenols, offering a scalable and clean-label platform for functional foods and nutraceuticals with enhanced stability, bioaccessibility, and therapeutic performance.