Naringin reduces starch digestibility via dual mechanisms: α-amylase inhibition and crystal type-dependent complexation with starches

This study investigated how starch crystal type governs naringin (NRG) interactions and its impact on α-amylase inhibition and starch digestibility. Three starches with distinct crystal structures were selected, including corn (A-type), potato (B-type), and pea (C-type). NRG exhibited dose-dependent α-amylase inhibition via static binding to the active pocket, as confirmed by molecular docking and fluorescence quenching. Complexation with NRG induced crystal type-dependent structural changes. B-type (potato) starch showed the highest complexation index and stronger interaction with NRG, accompanied by the greatest disruption of short-range ordered structure. Consequently, potato starch-NRG complexes displayed the highest increase in resistant starch content and the most sustained NRG release during simulated intestinal digestion. These findings demonstrate that starch crystal type critically determines NRG incorporation and subsequent digestion resistance, B-type starch showed greater potential for NRG incorporation and sustained release. This crystal-directed strategy provides a new paradigm for designing low-glycemic starch-based foods.