Stabilizing Oil-in-Water Emulsion with Amorphous and Granular Octenyl Succinic Anhydride Modified Starches

The effects of pre-gelatinization on the capacity of amorphous and granular octenyl succinic anhydride (OSA) starches as an emulsifier were compared. The full loss of the granular structure after gelatinization were confirmed by X-ray scattering measurements. The particle size of the emulsions prepared by granular starches with the degree of substitution of 0.021 and 0.045 was 717.8 and 391.5 nm, respectively, whereas it was only 307.2 and 283.9 nm of the amorphous OSA starch emulsions, respectively. Furthermore, after 30 days of storage, the particle size of granular OSA starch emulsions increased to 910.1 and 520.9 nm, respectively. However, this value only increased to 376.6 and 335.2 nm in emulsions stabilized with the amorphous OSA starch, respectively. These were attributed to an increased interfacial thickness, rate of interfacial adsorption, and compact packing on the surface, resulting from the flexible assembly behavior of amorphous starch chains compared to granular OSA. In addition, emulsions stabilized via amorphous OSA starches displayed a higher elastic moduli, indicating a greater number of interactions between starch chains and adjacent droplets.