The reaction of gelatin /gum arabic coacervate gels with
glutaraldehyde
Curt Thies
Polymer Research Section, Materials
Research, The National Cash Register Company, Dayton, Ohio 45409, USA
Received 1 September 1972; accepted 10 October 1972. Available online 9 July 2004.
Abstract
The consumption of glut by various gelatin/gum arabic (GGA) coacervate gels has been examined over a range of
conditions. Both acid- and alkali-precursor gelatins were used to form the coacervates. Glut consumptions by several gelatin gels were
also determined. All gels examined consumed 0.3 to 1.6 mmole glut/g gelatin. Acid and alkali GGA gels had similar
glut uptakes at 4°C. Glut consumption by acid-precursor GGA gels increased
significantly with increasing gelation temperature
(4–28°C) due to temperature-dependent changes in gel structure. The use of
commercial versus redistilled glut had no detectable effect upon glut uptakes.
Reaction of a gel with glut caused a high degree of insolubilization as a result of intermolecular crosslink
formation. Most treated gels were at least 85 wt% insoluble at 55°C in phosphate
buffer after 4–28 days extraction. That fraction of a gel solubilized by the extraction process contained both gelatin
and gum arabic. Thus, despite the fact that gum arabic has little tendency to react
with glut, it is effectively entrapped in the crosslinked GGA gel structure. Gels with lowest glut uptakes
were the most soluble ones. They also were the only ones with solubilities that increased upon treatment with
NaHSO3 before the gel fraction extraction process. Insolubilization of GGA gels by glut causes their swelling
behavior and composition to become essentially independent of pH. Composition
and swelling behavior of uncrosslinked gels vary
markedly with pH due to the reversible nature of the intermolecular bridges
responsible for gelation.
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