Optimization of Reaction Conditions to Control Physicochemical Properties of Octenyl Succinic Anhydride Modified Normal Maize Starch

This study investigated the optimization of the physicochemical properties of normal maize starch (NMS) by esterification with octenyl succinic anhydride (OSA). The synergistic effects of OSA addition time, temperature, and total reaction time on the degree of substitution (DS) and the physicochemical properties of starch were evaluated using a combination of single-factor experiments and Response Surface Methodology (RSM). FT-IR spectroscopy confirmed the successful incorporation of OSA groups into starch molecules, with the appearance of two characteristic absorption peaks at 1724 and 1572 cm⁻¹. Single-factor experiments revealed that a temperature of 40 °C, an OSA addition time of 2 h, and a total reaction time of 6 h effectively maximized the DS. These conditions balanced efficient esterification with the suppression of OSA hydrolysis and droplet aggregation. The resulting optimized OSA starch displayed lower gelatinization temperature and enthalpy, higher viscosity, more pronounced shear-thinning behavior, and greater resistance to retrogradation. Pearson correlation and simple linear regression analyses demonstrated that DS was negatively correlated with both ΔH and G′_max. The RSM model accurately predicted the optimal synthesis parameters (41.96 °C, 2.25 h OSA addition time, 6.9 h total reaction time), achieving a validated DS of 0.0258. This study provides valuable insights for producing starch-based additives in complex food systems.