Octenyl succinic anhydride (OSA)-modified starches: From molecular state to granular state

Starch is the second most abundant renewable biopolymer on Earth after cellulose, and is widely distributed in plant tissues such as leaves, stems, seeds, roots, and tubers. However, native starch has limited industrial applicability due to its poor water solubility and low process tolerance. To address these limitations, starch esterification with octenyl succinic anhydride (OSA) is conducted, which introduces hydrophobic substituents by partially substituting hydroxyl groups, resulting in OSA-modified starch (or OSA starch). OSA starch finds applications in both food and non-food products, including functional beverages, salad dressings, and biodegradable films, where it serves as an emulsifier, encapsulating agent, or fat replacer.

Most commercial OSA starches are derived from waxy or normal maize starches through OSA modification followed by enzymatic hydrolysis, rendering them water-soluble and amphiphilic at the molecular level. Interestingly, recent studies have proposed that OSA starch in its intact granular state—prior to enzymatic hydrolysis—can function as an effective Pickering stabilizer. This work will investigate the effect of modification parameters (degree of substitution, particle size and oil volume fraction) on the multi-scale characterization, combined with the formation rules of Pickering emulsions, and then introduce a “Green” hydrophobic modification using zein for novel lutein delivery. This study will promote the development and applications on the multi-scale characterization combined with functional features of starch-based Pickering emulsions.