Abstract: Acetylized sweet potato starches (ASPS) with various low degree of substitution (DS) prepared with Ac2Oand sweet potato starches (SPS) are very similiar to SPSaccording to the measurement of granular and surface structures by SEM, polarized light, X-rays diffraction.The surface structures of ASPSand SPSare observed really with the electro-conducting gum in the absence of the gold-plating method.Gelatinization temperatures of ASPSand SPSare (1) from 71.6-76.0-79.0 COto 65.5-67.0-70.0(℃) with DSfrom 0 to 0.1985; (2) increase firstly then decrease with NaCl concentration increasing from 0% to 25% ; (3) increase with glucose, sucrose, maltose concentration increasing from 0% to 25%; (4) decrease with the variation of pHvalues except neutral, particularly decrease sharp pHis under a strong base condition.For example, the gelatinization temperature is 10℃ when pH=13.3.Meanwhile the effects of glucose, sucrose, maltose, NaCl on gela-tinization temperature decrease with DSincreasing.

Key words: Acetylized starches, Sweet potato starches, Gelatinization temperature