Understanding the intrinsic and extrinsic properties of a starch branching enzyme II wheat mutant and their impact on glucose response

Corrado, Marina (2020) Understanding the intrinsic and extrinsic properties of a starch branching enzyme II wheat mutant and their impact on glucose response. Doctoral thesis, University of East Anglia.

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Abstract

Wheat is a major source of dietary carbohydrate but the starch in many wheat-based products is rapidly digested, causing a rapid increase in blood glucose levels after consumption. Previous research has developed a novel type of wheat carrying mutations in starch branching enzyme II a and b (sbeII) genes, characterised by altered starch structure, thought to be less susceptible to amylolysis. The sbeII wheat is known to have a higher amylose content than conventional wheat, but its processing performance, starch digestibility and glycaemic power have not yet been studied in detail.
The aims of this PhD project were to examine the intrinsic and extrinsic properties of starch from a sbeII wheat, to investigate its susceptibility to starch amylolysis in vitro, and explore its potential use to lower glycaemic response to wheat-based foods in vivo.
A series of in vitro studies were undertaken to characterise the starch and non-starch polysaccharide components of sbeII wheat and to determine the effects of hydrothermal processing on sbeII starch susceptibility to hydrolysis. These studies demonstrated that starch retrogradation is a key mechanism limiting starch amylolysis in foods made with sbeII wheat.
Based on this knowledge, two test foods (semolina pudding and bread) were then developed using sbeII wheat to measure the glycaemic impact of sbeII foods in vivo. Their effect on postprandial glycaemic response was determined in two double-blind cross-over intervention studies. Evidence from these in vivo studies suggested that sbeII bread can elicit a lower glycaemic response compared to the control bread, however, due to the relatively small size of the study cohort, the extent of the decrease in glycaemic response may need to be further investigated. Overall, these studies have advanced current understanding of sbeII wheat starch and its potential to improve glycaemic properties of wheat-based foods.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Nicola Veasy
Date Deposited:	07 Oct 2021 12:46
Last Modified:	07 Oct 2021 12:46
URI:	https://ueaeprints.uea.ac.uk/id/eprint/81600
DOI:

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