Abstract:

The acetylated potato starch was chemically gelatinized at the periphery of granules with aqueous calcium chloride (4 mol/L) at room temperature, and the remnant granules were obtained after removing the gelatinized starch at the periphery of granules. The original and remnant granules were analyzed for their size, substitution degree, crystal properties and thermal properties. The degree of substitution (DS) of acetylated potato starch was correlated with granular size. The smaller the granular size, the larger the DS. Acetyl groups were mainly distributed at the periphery of starch granules. The crystal structure of remnant granules was B-type, the same as that of original granules. The relative crystallinity and the peak gelatinization temperature of remnant granules became larger as the degree of gelatinization increased.

Key words: acetylation, remnant granule, substitution degree, crystal, gelatinization temperature