Abstract:

Kudzu starch was acetylated and cross-linked to improve its properties and thus broaden its applications. The
effect of amount of acetic anhydride, reaction temperature, reaction time and pH on the substitution degree of cross-linked
acetylated kudzu starch (CLAKS) was investigated by the wet method to establish the optimum conditions for forming
CLAKS. The structure and thermal properties of CLAKS were characterized by infrared spectroscopy (IR), differential
scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The results indicated that the optimum conditions for
preparing the modified starch were reaction temperature 30 ℃, reaction time 60 min and pH 8.5. After acetylation and crosslinking,
kudzu starch showed improvements in freeze/thaw stability, thermal viscosity stability, acid resistance and alkali
resistance. Its swelling powder was increased by acetylation but reduced by cross-linking. DSC analysis showed that the
peak onset temperature, peak temperature, peak end temperature and enthalpy change of the modified starch reduced, but its
thermal stability increased compared with those of the native starch.

Key words: kudzu starch, cross-linking, acetylation, process, property