Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
The purposes of chemically modifying starch 12 (see Chapter 9) and cellulose
are similar, but the corresponding derivatives of both polysaccharides perform
differently. For instance, nitrocelluoses perform better than nitrostarches as explosives
and thin films. In contrast to starch xanthate, cellulose xanthate finds wide
application in production of artificial silk. These are the earliest and most common
nonnutritive applications of cellulose and starch. Starch xanthates, and, particularly,
starch xanthides have been proposed as heavy-metal traps for sewage and water
basins.
19.3.1 ALCOHOLYZED AND PHENOLYZED STARCHES AND SUGAR
ALCOHOLS
Alcoholysis (and phenolysis) of starch provides D-glucopyranosides useful in production
of polyethers for rigid polyurethane foams and surfactants. Foams made
from these materials are flame resistant. Alkyl pyranosides can serve as biodegradable
surfactants and emulsifiers. Reduction of both polysaccharides generates polyols,
which are promising as binders in metal oxide nanopowder-based ceramics.
19.3.2 OXIDIZED STARCHES
Applications of oxidized cellulose and starches include preparation of wood veneer
glue, a joint cement consisting of cement mixed with gelatinized oxidized starch
and asbestos; gypsum board; and textile dressings and sizes. Sizes is perhaps the
largest application for oxidized starches and cellulose. Oxidized starches can be
components of phosphate-free detergents.
Starch dialdehyde, the product of oxidation of starch with periodate, acetalated
with glyoxal when admixed to pulp, increases the wet tensile strength of paper by
250%. It is also used to make paper sheets for thermal recording and in photolithography.
Polysaccharide dialdehyde acetals, hydrazones, oximes, hydrogen sulfite compounds,
and corresponding Schiff bases are known to increase the wet and dry
strength of additives to paper.
Several copolymers and condensates of oxidized polysaccharides with polymers
have been developed to form resins for coatings, molding powders, and materials
for immobilization of enzymes, for instance, alpha amylase adhesives for labels and
corrugated paper. Thin films are prepared in copolymerization of polysaccharide
dialdehydes with partially hydrolyzed poly(vinyl acetate), O-(carboxymethyl)cellulose,
and ethylene-vinyl alcohol.
Acidic oxidized polysaccharides, that is, polysaccharides with carboxylic
groups, can trap metal ions, and heavy metal salts of oxidized polysaccharides have
been suggested as dye mordants.
Oxidized polysaccharides possess binding properties with particles of artificial
fertilizers. They have potential applications also as detergent builders, scale-preventing
agents, and microencapsulating agents for aromas.
There exist a wide variety of medical applications for oxidized starches and their
derivatives. Powdered oxidized starch decreases gauze adherence to wounds. Calcium
derivatives have been proposed for treating hypocalcemia. The use of