Exploring the effect of OSA-esterified waxy corn starch on naringin solubility and the interactions in their self-assembled aggregates.

Octenyl succinic anhydride esterified waxy corn starches (OSAS) with five different molecular weights (MWs) were prepared by enzymatic hydrolysis and their effects on naringin solubility were studied. The MW of OSAS was found to significantly influence the amount of naringin embedded in the complex formed by self-aggregation. OSAS with medium MW (M-OSAS) formed complex with the highest naringin entrapment. This system showed an AL type water phase solubility curve (indicating a 1:1 stoichiometric inclusion complex) and an increase of 848.83 folds in naringin solubility. Further investigation on the interactions between M-OSAS and naringin using FTIR, XRD, DSC and NMR confirmed the encapsulation of naringin into the inner cavity of M-OSAS. TEM and particle size analysis indicated the complex was spherical in shape, having a mean particle size of 257.07 nm and size distribution of 10-1000 nm. This study has provided a basis for solubility enhancement of citrus flavonoids using OSAS.