Abstract:

Waxy maize starches wi出a moisture content. of 30% were treated with microwave radiation. The proper-ties of the native and the treated starches were then studied by using SEM , XRD , DSC and Brabender viscoamylo-graph.It is indicated that (1) after the radiation , the surfaces of the starches become porous with concavity; (2)microwave radiation enhances the X -ray intensities of the starches , decreases the swelling power , solubility , synere-sis and gelatinization enthalpy of the starches , and improves the gelatinization transition temperature and the corres-ponding range; and (3) the waxy maize starches treated by microwave is of an increased pasting temperature and a decreased viscosity with the viscosity pattem remains unchanged. The above-mentioned details reveal the interaction involving starch chains (amylose-amylose and amylose-amylopectin) in the amorphous and crystalline regions of the granules , which results in the fonnation of new crystallites with different stabilities and more ordered crystalline ar-ray in the starches.

Key words: microwave, waxy maize, starch, property