Chemical and Functional Properties of Food Saccharides
Chemical and Functional Properties of Food Saccharides
Chemical and Functional Properties of Food Saccharides
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© 2004 by CRC Press LLC<br />
capsule shells. (Hydroxyethyl)starch accelerates disintegration <strong>of</strong> tablets prepared<br />
by direct compression. It can also be used as a drug carrier. In wood pulp, (hydroxyethyl)starch<br />
decreases the amount <strong>of</strong> surface lint on paper. It is also a potential soil<br />
stabilizer. Alkylation <strong>of</strong> (hydroxyethyl)starch provides a biodegradable surfactant.<br />
(Hydroxyethyl)starch films have been reported to show negligible transmission <strong>of</strong><br />
oxygen.<br />
(Hydroxyethyl)starch has been extensively studied as a blood exp<strong>and</strong>er, sometimes<br />
in a partially hydrolyzed form. Bleeding volume index <strong>of</strong> hydroxyethyl starch<br />
is found to be similar to that <strong>of</strong> whole blood. A product <strong>of</strong> DS between 0.43 <strong>and</strong><br />
0.55 <strong>and</strong> an average molecular weight <strong>of</strong> 216,000 was found to be superior. (Hydroxyethyl)<br />
starch appears to be a superior anticoagulant. It is also used for cryopreservation<br />
<strong>of</strong> mammalian cells, including those <strong>of</strong> the bone marrow. Various useful<br />
application <strong>of</strong> O-(hydroxyethyl)starch blends with low- <strong>and</strong> high-molecular-weight<br />
compounds are reported. In combination with urea, (hydroxyethyl)starch is used as<br />
a size for hydrophobic synthetic yarns; with alkylaminopropylamines or acetylated<br />
starch <strong>and</strong> poly(vinylalcohol), (hydroxyethyl)starch is used as a corrosion inhibitor<br />
<strong>and</strong> a microgel precursor. Blends with borax, urea, <strong>and</strong> ethylene glycol constitute<br />
an aerosol for ironing garments. Blends <strong>of</strong> hydroxyethyl starch <strong>and</strong> (hydroxyethyl)cellulose<br />
are effective thickeners for textile printing <strong>and</strong> developing pastes for<br />
motion-picture films, x-ray films, <strong>and</strong> photographic paper. Starch-derived ethylene<br />
glycol <strong>and</strong> glycerol glycosides react with alkylene oxides <strong>and</strong> have been tested as<br />
biodegradable detergents <strong>and</strong> components <strong>of</strong> polyurethane foams. Water-resistant<br />
short-tack adhesives are formed by blending (hydroxyethyl)starch with formaldehyde–urea<br />
copolymers <strong>and</strong> polyethylene glycol dodecanoate.<br />
19.3.5 ACETALS<br />
The chemical <strong>and</strong> physical stability <strong>of</strong> formaldehyde-cross-linked starch made these<br />
materials one <strong>of</strong> the first starch-based plastics. Such products were fairly stable <strong>and</strong><br />
responded favorably to heat <strong>and</strong> pressure. As a result, they were soon applied as<br />
paper coatings <strong>and</strong> as thickeners for textile printing with dyes. Compounds from<br />
co-crosslinking with ketones were patented as adhesives for corrugated paperboard<br />
<strong>and</strong> water-stable sizing materials. Starch acetals were also used as plastics to impregnate<br />
fibrous substances, as a coating for heat-resistant fibers, as artificial lumber<br />
when mixed with sawdust, <strong>and</strong> as molding-compound binders, surfactants, <strong>and</strong><br />
further cross-linking agents. Starch–formaldehyde acetal was also used as a cotton<br />
fabric size to improve the whiteness <strong>of</strong> household cloth after washing.<br />
Adhesiveness <strong>of</strong> starch acetals can be improved by reacting starch with formaldehyde<br />
<strong>and</strong> ammonia or ammonium salts. The involvement <strong>of</strong> urea <strong>and</strong> amines in<br />
the acetalation <strong>of</strong>fers a group <strong>of</strong> novel materials.<br />
Protein–acetal compounds prepared with gelatin form sponges, which can be<br />
used instead <strong>of</strong> gauze <strong>and</strong> adhesive b<strong>and</strong>ages. Polycondensates <strong>of</strong> aldehydes with<br />
amides <strong>of</strong> unsaturated carboxylic acids after reaction with starch produce agents for<br />
impregnating textiles, leather, wood, <strong>and</strong> paper. Strengthening agents for paper are<br />
also prepared by grafting oxidized starch with acrylamides <strong>and</strong> converting them into<br />
amines, followed by cross-linking with formaldehyde.
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