Effect of pH and acetic anhydride concentration on physicochemical characteristics of acetylated sago starch

Acetylation is a method of chemically modified starch that can be used to improve the physicochemical properties of starch. The aim of the study was to obtain the pH and concentration of acetic anhydride which gave the best effect on the physicochemical characteristics of acetylated sago starch. The study was arranged using a completely randomized design with a factorial pattern in combination with a suspension pH of 7.0; 8.0; 9.0 and 10.0 with acetic anhydride concentrations of 3%, 6%, 9%, 12% and 15% (volume/weight). The parameters of research include acetyl percent, degree of substitution (DS), water holding capacity (WHC), oil holding capacity (OHC), swelling power, solubility and degree of clarity of the paste. The results at research showed that the combination suspension pH of 8 and 15% concentration of acetic anhydride gave optimal physicochemical characteristics of acetylated sago starch. The all concentrations of acetic anhydride (3 to 15%, v/w) were acetyl percent, DS, solubility and the degree of clarity of the paste increased with the increasing. The WHC and OHC tend the decreasing with the increasing concentration of acetic anhydride. Swelling power was stable with increasing concentration of acetic anhydride.