EFFECT OF OXIDATION AND HYDROXYPROPYLATION ON STRUCTURE AND PROPERTIES OF HIGH-AMYLOSE CORN STARCH, AND PREPARATION OF HYDROXYPROPYL OXIDIZED HIGH-AMYLOSE CORN STARCH

The aim of this study was to investigate the effect of oxidation and hydroxypropylation on the structure and properties of high-amylose corn starch (HACS) by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The crystalline structure of HACS belonged to the A type, while the amorphous region of HACS granules was mainly located on the side face. The manner of the oxidation was different from that of the hydroxypropylation for HACS. The oxidation mainly occurred in the crystalline region, whereas the hydroxypropylation mainly occurred in the amorphous region. The hydroxypropylation occurred unevenly on granules. The oxidation could enhance the blue value of HACS from 0.537 to 0.725. However, the blue value of HACS was not basically influenced by the hydroxypropylation. The oxidation and hydroxypropylation could improve the acid and alkali resistance, cold and hot viscosity stability of HACS. The oxidation and hydroxypropylation changed the thermal stability and melting process of HACS, that is, the difference in the enthalpy change between HACS and hydroxypropylated oxidized high-amylose corn starch (HOHACS) reached 75.1 J/g.