Starch chain architecture and digestibility: Mechanistic links, kinetic descriptors, and routes toward prediction

Despite extensive research on starch structure-digestibility relationships, a critical gap persists between structural characterization and predictive capability. This review examines how starch chain architecture influences digestibility across molecular, supramolecular, lamellar, and granular scales. It discusses how glycosidic linkages, helical conformations, amylose content, amylopectin branching, and chain-length distribution govern enzymatic hydrolysis kinetics and resistant starch formation. Processing and modification strategies that remodel starch chain structures to regulate digestion rates are also summarized. In addition, starch digestion kinetic models, including first-order, empirical, diffusion-reaction, and sigmoidal models, are evaluated in terms of their applicability and limitations. Finally, spectroscopic techniques and machine learning approaches are assessed for predicting starch digestibility from chain-level structural characteristics: current datasets remain small and heterogeneous, and the transferability and interpretation of these prediction models require further validation.