Unlocking the Potential of OSA Starch: Advanced Physical Strategies for High-Efficiency Pickering Emulsions and Broadened Applications

Starch has attracted much attention due to its abundant resources and wide application potential, but the inherent hydrophilicity and structural limitations of natural starch have limited its use in industrial applications. By introducing octenyl succinic anhydride (OSA) onto the surface of starch granules, its amphiphilic and emulsifying properties can be significantly enhanced. Studies have shown that a higher degree of substitution (DS) imparts excellent hydrophobicity to the modified starch, enabling Pickering emulsions prepared with it as an emulsifier to exhibit remarkable stability. However, during the esterification reaction, the placement and quantity of octenyl succinic (OS) groups grafted onto the OSA starch chain play a crucial role in determining the efficiency of the esterification process. Starting with the esterification reaction mode, this review analyzes the effects of reaction conditions, particle properties, and OS groups distribution on the esterification efficiency. The modulation of starch granule morphology and fine structure through various physical modification techniques, along with their role in facilitating esterification reactions, is summarized. Furthermore, it evaluates the factors related to the stability of OSA starch-based Pickering emulsions and describes their applications in delivery, packaging, three-dimensional printing, fat replacement, and baking. Finally, this paper discusses the challenges of and opportunities for increasing the OSA starch esterification reaction efficiency, providing a reference for future research on Pickering emulsions.