dc.contributor.author |
Evageliou, Vasiliki I. |
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dc.contributor.author |
Ryan, Patricia M. |
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dc.contributor.author |
Morris, Edwin R. |
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dc.date.accessioned |
2018-03-22T11:46:33Z |
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dc.date.available |
2018-03-22T11:46:33Z |
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dc.date.issued |
2018-03-09 |
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dc.identifier.citation |
Evageliou, V. I., Ryan, P. M. and Morris, E. R. (2018) 'Effect of monovalent cations on calcium-induced assemblies of kappa carrageenan', Food Hydrocolloids, In Press. doi:10.1016/j.foodhyd.2018.03.018 |
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dc.identifier.startpage |
1 |
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dc.identifier.endpage |
5 |
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dc.identifier.issn |
0268-005X |
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dc.identifier.uri |
http://hdl.handle.net/10468/5677 |
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dc.identifier.doi |
10.1016/j.foodhyd.2018.03.018 |
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dc.description.abstract |
The effect of Na+, K+ and Ca2+ cations on the thermal stability and aggregation of kappa carrageenan double helices has been explored by differential scanning calorimetry (DSC). Previous studies have shown that kappa carrageenan helices bind K+ cations, but not Na+. The kappa carrageenan used in this work was therefore in the Na+ salt form, to avoid complications from site-bound counterions to the polymer, and was studied at a fixed concentration of 1.0 wt % (∼25 mN w.r.t. sulfate groups). Na+, K+ and Ca2+ cations were added as chloride salts. Values of peak-maximum temperature (Tmax) in DSC cooling and heating scans (0.5 °C/min) increased progressively with increasing salt concentration, following the order Na+< Ca2+< K+, but greatest thermal hysteresis was seen with Ca2+. Our proposed interpretation is that Ca2+ cations "cement" the carrageenan helices together by binding directly between them, giving greater thermal stability, and thus greater hysteresis, than K+ cations which act indirectly by suppressing charge. On progressive addition of NaCl or KCl to solutions incorporating Ca2+ at concentrations of 5 mM or 12.5 mM (stoichiometric equivalence) the values of Tmax moved asymptotically towards those seen for the same concentrations of the monovalent cations in the absence of calcium, suggesting progressive displacement of site-bound Ca2+. Thus Tmax for the order–disorder transition was increased by KCl but reduced by NaCl, with the strange consequence that addition of NaCl lowered the transition temperature rather than raising it. |
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dc.format.mimetype |
application/pdf |
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dc.language.iso |
en |
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dc.publisher |
Elsevier |
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dc.relation.uri |
http://www.sciencedirect.com/science/article/pii/S0268005X17316806 |
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dc.rights |
© 2018 Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license. |
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dc.rights.uri |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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dc.subject |
Kappa carrageenan |
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dc.subject |
Differential scanning calorimetry |
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dc.subject |
Calcium ions |
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dc.subject |
Cation binding |
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dc.title |
Effect of monovalent cations on calcium-induced assemblies of kappa carrageenan |
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dc.type |
Article (peer-reviewed) |
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dc.internal.authorcontactother |
Edwin Morris, Food and Nutritional Sciences, University College Cork, Cork, Ireland+353-21-490-3000 Email: ed.morris@ucc.ie |
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dc.internal.availability |
Full text available |
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dc.check.info |
Access to this article is restricted until 12 months after publication by request of the publisher. |
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dc.check.date |
2019-03-09 |
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dc.date.updated |
2018-03-22T11:40:47Z |
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dc.description.version |
Accepted Version |
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dc.internal.rssid |
430914987 |
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dc.description.status |
Peer reviewed |
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dc.identifier.journaltitle |
Food Hydrocolloids |
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dc.internal.copyrightchecked |
No !!CORA!! |
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dc.internal.licenseacceptance |
Yes |
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dc.internal.IRISemailaddress |
ed.morris@ucc.ie |
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dc.internal.bibliocheck |
In Press March 2018. Update citation, start page, end page, volume, issue etc. |
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