Effect of monovalent cations on calcium-induced assemblies of kappa carrageenan

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dc.contributor.author Evageliou, Vasiliki I.
dc.contributor.author Ryan, Patricia M.
dc.contributor.author Morris, Edwin R.
dc.date.accessioned 2018-03-22T11:46:33Z
dc.date.available 2018-03-22T11:46:33Z
dc.date.issued 2018-03-09
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 en
dc.identifier.startpage 1 en
dc.identifier.endpage 5 en
dc.identifier.issn 0268-005X
dc.identifier.uri http://hdl.handle.net/10468/5677
dc.identifier.doi 10.1016/j.foodhyd.2018.03.018
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. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Elsevier en
dc.relation.uri http://www.sciencedirect.com/science/article/pii/S0268005X17316806
dc.rights © 2018 Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/4.0/ en
dc.subject Kappa carrageenan en
dc.subject Differential scanning calorimetry en
dc.subject Calcium ions en
dc.subject Cation binding en
dc.title Effect of monovalent cations on calcium-induced assemblies of kappa carrageenan en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother Edwin Morris, Food and Nutritional Sciences, University College Cork, Cork, Ireland+353-21-490-3000 Email: ed.morris@ucc.ie en
dc.internal.availability Full text available en
dc.check.info Access to this article is restricted until 12 months after publication by request of the publisher. en
dc.check.date 2019-03-09
dc.date.updated 2018-03-22T11:40:47Z
dc.description.version Accepted Version en
dc.internal.rssid 430914987
dc.description.status Peer reviewed en
dc.identifier.journaltitle Food Hydrocolloids en
dc.internal.copyrightchecked No !!CORA!! en
dc.internal.licenseacceptance Yes en
dc.internal.IRISemailaddress ed.morris@ucc.ie en
dc.internal.bibliocheck In Press March 2018. Update citation, start page, end page, volume, issue etc. en


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© 2018 Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license. Except where otherwise noted, this item's license is described as © 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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