The effects of liquid-starch ratio, concentration of sulphuric acid, a
nd glacial acetic acid on the degree of substitution of acetylated cas
sava starch were investigated. The optimum liquid starch ratio was 2.5
. The degree of substitution increased rapidly with sulphuric acid con
centration up to 0.36 M at a liquor-starch ratio of 2.5. The optimum c
oncentration of glacial acetic acid at liquor-starch ratio of 2.5 and
0.64 M sulphuric acid was 13.9 M with a reaction efficiency of 88%. Th
e acetylated cassava starch was more soluble than the native cassava s
tarch.