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Production and characterisation of two wheat‐bran fractions: an aleurone‐rich and a pericarp‐rich fraction

2005; Wiley; Volume: 49; Issue: 6 Linguagem: Inglês

10.1002/mnfr.200500016

1613-4133

Philip J. Harris, Ramesh R. Chavan, Lynnette R. Ferguson,

Microbial Metabolites in Food Biotechnology

Abstract Wheat bran is a good source of dietary fibre in the form of cell walls, but contains a number of different cell types. We describe a large‐scale procedure for the production of an aleurone‐rich and a pericarp‐rich fraction from hard, Australian wheat. The fractions were characterised by field‐emission scanning electron microscopy, by using a range of bright‐field stains, colour reagents, and fluorochromes, and by chemical analysis of the walls. The aleurone fraction included the seed coat with its cuticle. Only the pericarp walls showed a histochemical reaction for lignin. The concentrations of ester‐linked ferulic acid and (1 → 3),(1 → 4)‐β‐glucans were greater in the aleurone‐rich fraction than in the pericarp‐rich fraction. The results are consistent with the arabinoxylans in the walls of the pericarp‐rich fraction being more highly substituted with arabinose than those in the walls of the aleurone‐rich fraction. When the fractions were fed as a dietary supplement to rats and walls were isolated from the faeces, it was found that the pericarp walls were not degraded, but the aleurone walls were partially degraded.