Pasting properties of Aand B-type wheat starch granules and annealed starches in relation to swelling and solubility

Wheat starch contains two distinct groups of granules, A -type and B -type, which have different compositions and properties. The aim of this study was to investigate the differences in pasting properties of Aand B -type wheat starch granules and their annealed starches, and to relate them to swelling properties and solubility. Aand Btype wheat starch granules were fractionated. The differences in pasting properties between Aand B -type wheat starch granules depended on starch solids content. The A -type starch had a higher pasting viscosity at >= 8 % solids content, but the trend was reversed at a lower solids content (5 %). This cross -over phenomenon in the pasting viscosity can be explained because A -type wheat starch granules have more starch molecules leached out, while swelled less at high temperatures and are probably more rigid than B -type wheat starch granules. This is the first study to show the cross -over in the pasting viscosity-starch concentration between A -type and B -type wheat starches and that B -type wheat starch has higher pasting viscosity than A -type at a low solids content. When annealed in warm water, both annealed Aand B -type wheat starch granules had higher pasting viscosities than untreated counterparts by altering the swelling of starch.