Drying and Rehydration of Calcium Alginate Gels

Vreeker, R.; Li, L.; Fang, Y.; Appelqvist, I.; Mendes, E.

Drying and Rehydration of Calcium Alginate Gels

Title

Drying and Rehydration of Calcium Alginate Gels

Author

Vreeker, R.
Li, L.
Fang, Y.
Appelqvist, I.
Mendes, E.

Faculty

Applied Sciences

Department

DelftChemTech

Date

2008-06-26

Abstract

In this paper, we study the rehydration properties of air-dried calcium alginate gel beads. Rehydration is shown to depend on alginate source (i.e. mannuronic to guluronic acid ratio) and the salt concentration in the rehydration medium. Rehydration curves are described adequately by the empirical Weibull equation. Wide-angle X-ray diffraction measurements are performed to obtain information on the microstructure of dried alginate gels. The X-ray diffraction patterns provide evidence for formation of ordered domains in which alginate polymers are laterally associated. Formation of ordered structures during drying is found to have a large impact on rehydration properties. Lateral association of alginate chains is reduced (and rehydration improved) by removing excess calcium ions from the gel beads in a washing step prior to air drying. In addition, rehydration properties of mixed alginate–carboxymethyl cellulose (CMC) gel beads are investigated. The presence of CMC in the gel matrix is found to reduce lateral association of alginate chains during drying and to improve rehydration properties.

Subject

Alginate
Egg-box
Aggregation
Drying
Rehydration
Weibull

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http://resolver.tudelft.nl/uuid:4b877790-5f9d-46e8-babb-9fdd92c72eed

Publisher

Springer

ISSN

1557-1866

Source

Food Biophysics, 3 (4)

Part of collection

Institutional Repository