Facile Preparation of Starch Triacetates

Commercial high-amylose com, ordinary com and potato starches 'were fully acetyl"ted by reacting the starches at 123°C for 5 h in fourfold quantities of acetic anhydride to which 11 010 (w;'w 5t"rch) of sodium hydroxide catalyst had been added as 50 010 aqueous solution. Intrinsic viscosities of the starches regenerated from their esters 'were slightly lower than the 'values for the corresponding umeacted starches and indicated that only minor degradation hat ocwrred during acetylation. Amylose obtained by the butanol fractionation of com starch was also readily acetylated by this procedure. However, commercial potato amylose required removal of the small amount of magnesium SIIlfate present to achie·ve both full acetylation (44.8 Ofo acetyl) and minimum depolymerization of the starch.