Structural Change of Wheat Starch Granule by Ball-mill Treatment

Abstract

Wheat starch granules were perfectly damaged but not cracked to pieces with rolling type ball-mill treatment for a long period (320 h), however, the granule surface changed from smooth to rough. The properties (amylase susceptivity and water absorption activity) of treated starch changed distinctly after 10 h of treatment. DSC results and X-ray diffraction patterns of treated samples also showed the same tendency. It was concluded that ball-mill treatment gelatizes starch granules over 10 h without water and heat. GPCs of a starch sample and a debranched sample showed that amylopectin was degraded and the cluster size fragment possibly liberated. Long-term treatment makes the molecular size of both components of starch small. A HPAEC analysis showed the liberation of very short chains with long-term treatment. A ¹³C solid-state-NMR spectra of starch samples suggests that disruption occurs at the glycosidic linkage during treatment.