Processing of novel elevated amylose wheats: functional properties and starch digestibility of extruded products.

Different types of novel wheat lines with different starch contents and amylose/amylopectin ratios, relating to defined alterations in the number and activity of starch synthase IIa genes, were processed by pilot-plant extrusion. Two types of products were produced: pure wholemeal products and breakfast cereals made from wholemeal/maize blends. Lower apparent shear viscosity was obtained in the extruder with lower starch content and higher amylose/amylopectin ratio flours (SSIIa-deficient line).

Influence of extrusion and digestion on the nanostructure of high-amylose maize starch.

An in-depth characterization of the structural changes undergone by high-amylose starch after extrusion and digestion with a pancreatic alpha-amylase has been carried out. The combination of USAXS, SAXS, XRD, and SEM techniques has provided a wide "picture" of the morphological transformations of starch, covering a length scale from approximately 0.3 nm to approximately 230 microm.