Preparation and properties of oxidized starch with high degree of oxidation

A highly efficient method for preparing oxidized starches with a high degree of oxidation (DO) was developed, using CuSO 4 and H 2O 2 respectively as a catalyst and an oxidant. The effect of different parameters including starch origin, oxidant content, temperature, catalyst content, and reaction time on the DO was investigated systematically. In the present study, only 0.5% of catalyst was added, and the reaction time could be reduced to 1 h, while in the previous study the reaction time of 72 h was necessary to achieve almost the same DO without a catalyst. The structures and properties of oxidized starches were characterized by FT-IR, DSC, TGA, XRD, and transmittance light testing. The oxidation reduced the intrinsic viscosity and thermal stability of the oxidized starches, and could change the crystalline structures into amorphous states when the DO reached 56.3%. When temperature and/or DO increased, the transmittance of suspended solution of oxidized starch increased correspondingly. © 2011 Published by Elsevier Ltd.