Study on the morphology,crystalline structure,and thermal properties of Fritillaria ussuriensis Maxim. starch acetates with different degrees of substitution

Fritillaria ussuriensis Maxim. starch acetates with different degrees of substitution (DSs) were prepared by reacting native starch with glacial acetic acid/acetic anhydride using sulfuric acid as catalyst. XRD of acetylated starch revealed that there was loss of crystallinity with increasing DS. The carbonyl group signal at 1750 cm⁻¹ appeared in the FTIR spectra. The intensity of this peak increased whereas the intensity of the hydroxyl groups at 3000–3600 cm⁻¹ decreased. The thermal behavior of the samples was investigated and the results showed that the acetylation decreased the gelatinization temperatures and ΔH_gel, and thermal stability of high DS acetylated starch (DS = 2.82) was much better than that of the original starch and partially substitute starch acetate (DS = 1.52). The SEM suggested that most of the starch granules were disintegrated into many visible fragments along with the increasing of DS. The starch acetate with different DS prepared in this paper has many potential uses in food and pharmaceutical applications for its lower gelatinization temperature and thermal stability properties.