The effect of physical damage on the molecular structure of wheat starch

Physically damaged wheat-starch granules are partly soluble in cold water and, on complete dissolution in methyl sulphoxide, show a limiting viscosity number lower than that of the undamaged granules. Extraction of damaged granules with cold water preferentially leaches out amylopectin of low molecular weight. Aqueous extracts of a commercially milled wheat-flour contained pentosan and a-d-glucan, the latter consisting of 99% of amylopectin and <1% of linear glucan. These findings differ from those of previous work on hot aqueous leaching of undamaged starch granules where amylose was preferentially extracted. © 1984.