J. M. Jones

Dietary fibre: new frontiers for food and health.

Wheat is a major source of fibre in the human diet; the major component being arabinoxylan (AX) which accounts for about 20% and 2% of the dry weight of bran and white flour fractions, respectively. Approximately 25% of the AX in flour is water-soluble, whereas most of that in bran is insoluble. Apart from its intrinsic health benefits, AX, and particularly insoluble AX, also contains high levels of bound phenolic acids (principally ferulic acid) which may have health benefits when released by fermentation in the colon. Work in the HEALTHGRAIN programme has identified substantial variation in the contents of dietary fibre components in wheat genotypes and is determining the genetic control of AX synthesis in order to establish molecular markers for use in plant breeding. Detailed analysis of AX amount and composition across the wheat endosperm has shown the existence of gradients which can be exploited to produce mill streams with defined health benefits.