Exploiting natural variation to improve the content and composition of dietary fibre in wheat grain: A review

Wheat is the major staple food in most temperate countries, including Europe and North America. In addition to providing energy and protein it is a significant source of a number of essential or beneficial components, including B vitamins, minerals, and dietary fibre. Cereal fibre has established benefits in reducing the risk of several chronic diseases but the consumption of fibre is below the recommended daily intake in the typical “Western diet”. Improving the content and composition of wheat fibre is therefore an attractive strategy to improve the health of large populations at low cost. The major dietary fibre components of wheat grain are arabinoxylan and β-glucan. Both vary in their amount, composition, and properties in different grain fractions, with white flour being lower in total fibre than bran but having a higher proportion of soluble fibre. There is significant variation in the amounts and structures of arabinoxylan and β-glucan in bread wheat genotypes, including commercial cultivars from different regions of the world, old landraces and exotic lines. This variation is also highly heritable, which should allow plant breeders to develop improved cultivars. Gradients in fibre composition and content within the grain may also allow millers to produce specialist high fibre flours