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

ABSTRACT

High-amylose starch branching enzyme II (sbeII) mutant wheat has potential to be low-glycaemic compared to conventional wheat; however, the effects of bread made from sbeII wheat flour on glycaemic response and product quality require investigation. We report the impact of white bread made from sbeII wheat flour on in vitro starch digestibility and product quality, and on postprandial glycaemia in vivo, compared to an isoglucidic wild-type (WT) control white bread. Starch in sbeII bread was ∼20% less susceptible to in vitro amylolysis leading to ∼15% lower glycaemic response measured in vivo, compared to the WT control bread, without major effects on bread appearance or texture, measured instrumentally. Despite the early termination of the in vivo intervention study due to the COVID-19 outbreak (n = 8 out of 19), results from this study indicate that sbeII wheat produces bread with lower starch digestibility than conventional white bread.