Total AC of cereals is thought to be mainly due to polyphenols,
and particularly to phenolic acids, most of which are associated
with dietary fibre, constituting a ‘‘dietary fibre-phenolic acid’’
complex. AC determined in residues of aqueous-organic extracts
corresponds to the phenolics associated with dietary fibre, which,
as noted earlier, could be released during colonic fermentation.
Along these lines, Serpen et al. (2007) reported a high contribution
(10–44%) of insoluble matter to the total AC of some cereal-products
(wheat bran, breakfast cereal and oat flour).