Characterization of Wheat Starch A- and B-type Granule Microstructure and Reactivity across Normal, Partial Waxy, and Waxy Backgrounds
World production of starch for food and industrial markets approaches 40 million metric tons per annum. Wheat, with its ability to produce starches of variable amylose content not presently available with corn, has great potential to make inroads into starch markets. As the majority of isolated starch utilized in food applications is chemically modified to improve starch properties for an intended use, it will be critical to develop high quality, wheat-based, modified starch products that will prove competitive in prime markets. This study will investigate factors that influence wheat starch granule reactivity to understand conditions required to produce quality, value-added starches from wheat. Starch chemical modification processes are influenced by granule chemical composition and microstructure. Wheat starch possesses two distinct starch
granule populations (A- and B-type), which exhibit differential granule sizes, compositions and behaviors. The recent development of partial waxy and waxy wheat lines with reduced amylose contents and altered amylopectin structure, has introduced greater compositional differences between cultivars. No study has addressed how the chemical modification of wheat starch might be affected by the differential size and composition of the A- and B- type granules. Likewise, no information exists as to how differences in amylose content may impact wheat starch granule reactivity. Knowledge of factors impacting granule reactivity will provide critical information needed to maximize quality and industrial potential of novel wheat starch products.