Effects of dry heating, acetylation, and acid pre-treatments on modification of potato starch with octenyl succinic anhydride (OSA)

Abstract

Octenyl succinic anhydride (OSA) starch is widely used to stabilize emulsions. Nevertheless, the poor compatibility of starch with hydrophobic groups has restricted the performance of OSA modification. In this work, potato starch was pre-treated once or twice (dry heating, acetylation, and acid modification) prior to OSA modification. Pre-treatments increased the degree of substitution (DS), hydrophobicity, hydrophilicity, and decreased amylose content of OSA starches, with dual pre-treatments having greater effects. Among all pre-treatments, acid modification followed by dry heating resulted in the greatest OSA modification (DS: 0.015) and water-binding capacity (155%). Meanwhile, acid modification followed by acetylation produced OSA starch with the highest oil-binding capacity (290%). Scanning electron microscopy revealed that the granular deformation of dual pre-treated OSA starches was greater compared to single pre-treated and non-pre-treated OSA starches (O). Dual pre-treated OSA starches (ADO, 7%; ACO, 8%) had lower amylose contents than those of single pre-treated (AO: 12%, CO: 17%, DO: 21%) and O (36%). All the pre-treatments reduced the setback viscosity of OSA starch to a lower range (70–394 cP), simultaneously decreasing their retrograde tendency. This study suggested that dual pre-treatments could improve the efficiency of OSA modification and produce OSA starch with greater emulsifying potential.