Properties, structural characterization of ozone-induced esterified starch for Pickering emulsions

A green preparation method for dual-modified starch via ozonation and ferulic acid (FA) esterification was proposed. Unlike traditional chemical modification (e.g., acid hydrolysis or toxic cross-linking agents), it uses no harmful reagents, works under mild conditions, produces clean by-products, and significantly reduces environmental burden. Ozone oxidation - FA esterified corn starch (FAO) was used as a stabilizer for Pickering emulsions, and its structure, functionality, and emulsion properties were systematically analyzed. The results shows that ozonation introduced carboxyl/carbonyl groups into corn starch, destroyed its crystalline structure, and formed surface micro-pits and cracks, thereby significantly improving the esterification efficiency of FA. This synergistic modification reduces the hydrophilicity of CS, with the contact angle of CS increasing from 28.6° to 73.5°. FAO-2 exhibits the optimal thermal stability (T p = 72.31 °C, ΔH = 13.5 J/g). Moreover, the Pickering emulsion prepared with FAO-2 shows the highest stability, featuring the lowest Turbiscan Stability Index (TSI = 0.21). Rheology analysis confirmed the gel-like behavior (tan δ = 0.082) and shear resistance of FAO-2. This study confirmed that ozonation and FA esterification can synergistically enhance starch performance, providing a new approach for the development of green and efficient emulsion stabilizers. • Pretreatment with ozone oxidation enhanced the esterification efficiency of starch. • Appropriate ozone oxidation increased carboxyl/carbonyl contents as active sites. • Dual-modification significantly improved starch's ability to stabilize Pickering emulsions. • The Pickering emulsion stabilized by esterified starch (2 h oxidation) has the lowest TSI.