Sequential alkaline extraction and alkaline hydrogen peroxide (AHP) bl
eaching have been used to prepare corn fiber gum in yields ranging fro
m 21 to 40%, depending on the pH of the extraction medium. The pH was
adjusted by using different ratios of NaOH and Ca(OH)(2). The whitest
product was obtained after AHP bleaching of the extract obtained using
the lowest pH value. In order for the product gum to give its charact
eristic clear and low viscosity solutions, it was necessary to remove
starch from the corn fiber substrate using alpha-amylase. The water-in
soluble hemicellulose A fraction, a minor component, was removed by ne
utralizing AHP-treated extracts before ethanol precipitation of the us
eful hemicellulose B (corn fiber gum) fraction. At ambient temperature
, AHP bleaching was near optimal after approximate to 2 hr under the p
rocessing conditions used. High ratios of arabinose (39%) to xylose (5
0%) were present in the corn fiber gum extracted under various alkalin
e conditions, and the H2O2 processing step did not significantly alter
these ratios. The same low levels of galactose (7%) and glucuronic ac
id (4%) were present regardless of the extraction conditions. Molecula
r mass of the corn fiber gum preparations ranged from 2.78 x 10(5) for
the material extracted with Ca(OH)2 to 3.94 x 10(5) for the material
extracted with NaOH. Molecular mass was unaffected by the H2O2 present
in the second processing step. As expected for a carbohydrate polymer
with a rather low uronic acid content, solution viscosities were unaf
fected by the presence of salt.