Involvement of Anion-Specific Effects in Changes in the Gelation and Thermodynamic Properties of Calcium Alginate Hydrogel
The gelation process and hydrogel properties of calcium salt-induced alginate hydrogels are influenced by anion-specific effects. In this study, we investigated the effects of CaSO<sub>4</sub>, CaI<sub>2</sub>, and Ca(C<sub>5</sub>H<sub>9</sub>O<sub...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Foods |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-8158/14/4/634 |
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| Summary: | The gelation process and hydrogel properties of calcium salt-induced alginate hydrogels are influenced by anion-specific effects. In this study, we investigated the effects of CaSO<sub>4</sub>, CaI<sub>2</sub>, and Ca(C<sub>5</sub>H<sub>9</sub>O<sub>3</sub>)<sub>2</sub> [calcium β-hydroxy-β-methylbutyrate, CaHMB] on the gelation behavior of alginate hydrogels, using various mannuronic/guluronic acid (M/G) ratios to elucidate the underlying mechanisms of anion-specific effects. Here, at a high M/G ratio (2:1), the gelation time of CaSO<sub>4</sub>, as a low-solubility calcium source, delayed the formation of the calcium alginate hydrogel. The gelation time was 1.8 times that of the high-solubility calcium source CaHMB. Strongly hydrated ions (such as SO<sub>4</sub><sup>2−</sup> and C<sub>5</sub>H<sub>9</sub>O<sub>3</sub><sup>−</sup>) caused the removal of water molecules from polysaccharide chains, resulting in the formation of small pores on the pore wall. Moreover, weakly hydrated chaotropic anions (I<sup>−</sup>) promoted the binding of alginate polysaccharide chains and water molecules, resulting in the slower thermal decomposition of water inside the gel. However, when the M/G ratio was reduced to 1:1 or 1:2, the influence of the three calcium salts on the water and thermodynamic properties of the hydrogels decreased, indicating that the anion-specific effect weakened. This study highlights the importance of anion-specific effects on the properties of alginate hydrogels and provides insights into the utilization of these effects to fabricate functional hydrogels with variable properties. |
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| ISSN: | 2304-8158 |