Differential impacts of porous starch versus its octenyl succinic anhydride-modified counterpart on naringin encapsulation, solubilization, and in vitro release

The aim of this work was to evaluate the potentials of porous starch (PS) and its octenyl succinic anhydride modified product (OSAPS) as efficient carriers for loading naringin (NA), focusing on encapsulation efficiency (EE, the percentage of adsorbed naringin relative to its initial amount), drug loading (DL, the percentage of naringin in the complex), structural alterations, solubilization and in vitro release of NA using unmodified starch (UMS) and NA as controls. Both the pore diameter and S BET value of PS decreased after esterification with OSA, and a thinner strip-shaped NA (~145 nm) was observed in the OSAPS-NA complex and (~150 nm) in the PS-NA complex. OSAPS exhibited reduced short-range ordered structure, as indicated by a lower R1047/1022 (0.73) compared to PS (0.77). Meanwhile, lowest crystallinity (12.81 %) of NA was found in OSAPS-NA. OSAPS-NA exhibited higher EE and DL for NA than PS-NA and a significant increase in NA saturated solubility in deionized water (by 11.63-fold) and simulated digestive fluids (by 24.95-fold) compared to raw NA. OSAPS contained higher proportions of slowly digestible starch and exhibited a lower digestion rate compared to PS, resulting in a longer time for NA release from its complex during the digestion.