Effect of the extrusion on the structure and properties of broken rice starch

The impact of the extrusion treatment on the structure and properties of broken rice starch were investigated.The crystal structure and appearance features of the broken rice starch granules were observed using X-ray diffraction analysis and scanning electron microscopy before and after the extrusion processing.It was found that the crystallinity of broken rice starch granules was reduced significantly after extrusion processing.The result displayed the starch granules were aggregated and its granules exhibited irregular shape.The solubility, swelling power, pasting properties and enzymatic susceptibility to α-amylase were measured.After extrusion, the solubility was sharply increased, whereas the swelling force was decreased.All of pasting parameters were cut down, which were peak, trough, breakdown, final and setback viscosities reduced from 2343, 1209 and 446cP to 114, 49 and 94cP, pasting temperature reduced from 78.8℃ to 55.0℃ and peak time shortened from 5.82min to 1.85min, respectively.The enzymatic susceptibility of starch was significantly improved.