Dietary fibre fractions were prepared following the
analytical procedure of Prosky, Asp, Schweizer, De
Vreis and Furda (1988). Brie¯y, samples are gelatinised
at 100C with termamyl (heat stable a-amylase) to
hydrolyse digestible starch and then enzymatically
digested with protease and amyloglucosidase to remove
any digestible proteins. The mixture is filtered and the
residue washed with water, collecting the filtrate and the
washing solution. The residue, washed with ethanol and
acetone, contains insoluble salts, undigested proteins
and the insoluble fraction of dietary fibre.
Ethanol is added to the collected filtrates to precipitate
the soluble fraction of dietary fibre. The precipitate, filtered
and washed with ethanol and acetone, contains
minerals, undigested proteins and the soluble fraction of
dietary fibre.