Cereal Chem 46:44 - 55. | VIEW
Flour Constituents Affecting MacMichael Viscosity.
W. F. Sollars. Copyright 1969 by the American Association of Cereal Chemists, Inc.
Conventional reconstitution procedures gave reconstituted wheat flours whose MacMichael viscosities were only half those of the parent flours, or less. Water-extraction of flours gave residues whose viscosities were much higher than the values obtained with the original unfractionated flours and which retained varietal viscosity differences. Combinations of water-extracts and residues from the same flour gave viscosities almost identical with those of the parent flour. Interchanges of water-extracts and residues between different flours showed that the water-extract accounted for part of the varietal viscosity differences. The water- extracts were separated into the dialyzables and the nondialyzables. The dialyzables lowered the viscosities of the residues more than did the total extract and showed a close relation to the viscosity values of the original unfractionated flours. Nondialyzables contained most of the water-soluble proteins and pentosans but had little or no effect on viscosity. Gluten, tailings, and starch could be reconstituted to residues whose viscosity matched closely those of residues from water-extraction of flours. Interchange experiments with reconstituted residues showed that the flour fraction causing the high residue viscosity and responsible for varietal differences was the gluten. Only in one experiment involving two soft wheats with a small viscosity difference did the tailings cause part of the viscosity difference, and starch never played a significant role in MacMichael viscosity.