Influence of octenyl succinic anhydride (OSA) treatment on the structural, physicochemical, and functional properties of starch: A review.

Octenyl succinic anhydride (OSA) modification is a widely adopted esterification technique that converts native starch into an amphiphilic biopolymer with enhanced functional performance. Under mild alkaline conditions, OSA molecules react with hydroxyl groups in amorphous domains of starch granules, forming stable ester linkages that introduce hydrophobic octenyl succinyl substituents without disrupting the native crystalline polymorph. These structural modifications cause reduced gelatinization temperature and enthalpy, improved swelling and solubility, increased paste viscosity and clarity, and suppressed retrogradation due to steric hindrance. OSA-modified starch shows superior interfacial activity, enabling stabilization of oil-in-water emulsions and enhanced encapsulation of bioactive. Dual-modification strategies such as heat-moisture treatment, ultrasonication, cold plasma, and enzymatic pretreatment improve emulsification efficiency, freeze-thaw stability, and controlled release. OSA-modified starches are safe food additives and clean-label alternatives for foods, nutraceutical delivery, and biodegradable packaging applications.