Effects of octenylsuccinylation on the structure and properties of high-amylose maize starch

Structural changes from the octenylsuccinylation of high-amylose maize starch were investigated by FT-IR and differential scanning calorimetry (DSC), with observations made on the distribution of octenyl succinate (OS) groups using confocal laser scanning microscopy (CLSM). Results of the octenylsuccinylation on in vitro digestion property (uncooked and cooked) were also determined. DSC data revealed a broad gelatinization endothermic peak ranged from 72.5 °C to 96.4 °C for the native starch, and a downward trend for products of increasing degree of substitution (DS). The OS groups appeared to be distributed throughout the OS-starch granules, especially on the surface. Octenylsuccinylation decreased the slowly digestible starch content of low DS OS-starch after cooking, while increased the resistant starch (RS) level in uncooked OS-starch. Even though uncooked OS-starch (DS ≈ 0.04) has 86.3% RS content, its RS content was reduced to 7.5% after cooking.