C;ell wall cross-linking can have a substantial effect on the properties of
the wall. To estimate cross-linking between arabinoxylans) in cereal fibre
s, dehydrodiferulate levels were measured in soluble and insoluble dietary
fibre (SDF and IDF) isolated from whole grains of maize (Zea mays L), wheat
(Triticum. aestivum L), spelt (Triticum spelta L), rice (Oryza sativa L),
wild rice (Zizania aquatica Lj, barley (Hordeum vulgare L), rye (Secale cer
eale Lj, oat (Avena ena sativa L) and millet (Panicum miliaceum L). After s
aponification of the cereal fibres the extracts were investigated for dehyd
rodimers of ferulic acid using GLC-MS and GLC-FID. From most cereal IDF the
whole spectrum of dehydrodiferulic acids (DFAs) (8-5 '-, 8-8 '-, 5-5 '-, 8
-O-4 '- and 4-O-5 ' -coupled) could be identified. The absolute contents of
total DFAs ranged between 2.4 and 12.6 mg g(-1). With the exception of 4-O
-5 ' -coupled DFA, the whole range of DFAs was also detected from cereal SD
F but only in amounts 40-230 mug g(-1). It was estimated that arabinoxylans
of cereal IDF contain 8-39 times more diferulates than arabinoxylans of ce
real SDF (where measurement of DFA levels in SDF was possible). In cereal I
DF, 8-5 ' -coupled dimers dominated. whereas in cereal SDF, 8-8 ' -coupled
dimers were relatively enhanced and often became the major dimers. (C) 2001
Society of Chemical Industry.