Resistant starch nanoparticles: Navigating the trade-offs between fabrication, structure, and function

This review critically examines recent advances in resistant starch nanoparticles (RSNPs), focusing on the relationships among fabrication routes, multiscale structure, digestive resistance, and functional performance. Physical, chemical, enzymatic, and combined methods are compared in terms of particle-size control, structural preservation, processing efficiency, and scale-up constraints. Particular attention is given to how molecular architecture, ordered structure, morphology, and dynamic interactions during digestion influence bioactive delivery, Pickering emulsion stabilization, and colonic fermentation. Current evidence also reveals major limitations, including inconsistent RSNP definitions, limited process-yield data, scarce in vivo validation, and emerging safety concerns. Future research should integrate standardized digestion assays, dynamic multiscale characterization, food-matrix validation, and rigorous safety assessment to support mechanism-based RSNP design.