Mining the A.E. Watkins Wheat Landrace Collection for Variation in Starch Digestibility Using a New High-Throughput Assay.

Breeding for less digestible starch in wheat can improve the health impact of bread and other wheat foods. The application of forward genetic approaches has lately opened opportunities for the discovery of new genes that influence the digestibility of starch, without the burden of detrimental effects on yield or on pasta and bread-making quality. In this study we developed a high-throughput in vitro starch digestibility assay (HTA) for use in forward genetic approaches to screen wheat germplasm.

Loss of starch synthase IIIa changes starch molecular structure and granule morphology in grains of hexaploid bread wheat.

Starch synthase III plays a key role in starch biosynthesis and is highly expressed in developing wheat grains. To understand the contribution of SSIII to starch and grain properties, we developed wheat ssIIIa mutants in the elite cultivar Cadenza using in silico TILLING in a mutagenized population. SSIIIa protein was undetectable by immunoblot analysis in triple ssIIIa mutants carrying mutations in each homoeologous copy of ssIIIa (A, B and D).

Effect of high-amylose wheat mutants on starch digestibility in bread, product quality, postprandial satiety and glycaemic response.

High-amylose () mutant wheat has potential to be low-glycaemic compared to conventional wheat; however, the effects of bread made from wheat flour on glycaemic response and product quality require investigation. We report the impact of white bread made from wheat flour on starch digestibility and product quality, and on postprandial glycaemia , compared to an isoglucidic wild-type (WT) control white bread. Starch in bread was ∼20% less susceptible to amylolysis leading to ∼15% lower glycaemic response measured , compared to the WT control bread, without major effects on bread appearance or texture, measured instrumentally.

Effect of semolina pudding prepared from starch branching enzyme IIa and b mutant wheat on glycaemic response in vitro and in vivo: a randomised controlled pilot study.

Refined starchy foods are usually rapidly digested, leading to poor glycaemic control, but not all starchy foods are the same. Complex carbohydrates like resistant starch (RS) have been shown to reduce the metabolic risk factors for chronic diseases such as hyperglycaemia and overweight. The aim of the project was to develop a semolina-based food made from a starch branching enzyme II (sbeIIa/b-AB) durum wheat mutant with a high RS content and to measure its glycaemic index using a double-blind randomised pilot study.