Acetylation of High‐Amylose Corn Starch. Influence of Pretreatment Techniques on Reaction Rate and Triacetate Solubility

Abstract

Abstract Various pretreatment methods for starch were applied to a commercial high‐amylose corn starch of apparent 71% amylose content before acetylation in acetic anhydride‐pyridine at 100°C. Pretreatments that involved major granule disintegration, such as solubilization of the starch in DMSO or agitation in hot water followed by precipitation of the starches with ethanol and drying, were most effective for obtaining rapid and complete acetylation without degradation. The resulting triacetates, in contrast to the others, were completely soluble in chlorinated hydrocarbon solvents and therefore would be preferred for film and fiber preparation.