Surface Derivatization of Corn Starch Granules

ABSTRACT Commercial corn starch, treated with stearoyl chloride in carbon tetrachloride and triethylamine, is surface-derivatized without noticeable swelling. Granules that are reacted with chloroacetic acid under similar conditions undergo surface etherification, visibly identified by their color binding with fuchsin. Interestingly, the dye experiment indicates surface-derivatization as well as derivatization of the granule central interior, suggesting reagent penetration to the granule interior through pores and derivatization of a lower density porous center. Esterification of corn starch granules treated with glucoamylase have five times greater esterification than normal corn starch granules. Placed in water, these and palmitoylated granules have a fatty feel to the fingers. Stearoylated corn and amaranth starches showed indications for use as fat replacers in frozen desserts.