Characterisation of heat-induced protein aggregation in whey protein isolate and the influence of aggregation on the availability of amino groups as measured by the ortho-phthaldialdehyde (OPA) and trinitrobenzenesulfonic acid (TNBS) methods

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dc.contributor.authorMulcahy, Eve M.
dc.contributor.authorFargier-Lagrange, Maéva
dc.contributor.authorMulvihill, Daniel M.
dc.contributor.authorO'Mahony, James A.
dc.contributor.funderDepartment of Agriculture, Food and the Marineen
dc.date.accessioned2017-08-17T12:39:57Z
dc.date.available2017-08-17T12:39:57Z
dc.date.issued2017-02-02
dc.date.updated2017-08-17T12:27:46Z
dc.description.abstractWhey protein isolate (WPI) solutions, with different levels of aggregated protein, were prepared by heating (5% protein, pH 7, 90 °C for 30 min) WPI solutions with either 20 mM added NaCl (WPI + NaCl), 5 mM N-ethylmaleimide (WPI + NEM) or 20 mM added NaCl and 5 mM NEM (WPI + NaCl + NEM). Gel electrophoresis demonstrated that the heated WPI and WPI + NaCl solutions had higher levels of aggregated protein, due to more covalent interactions between proteins, than the heated WPI + NEM and WPI + NaCl + NEM solutions. There were marked differences in the levels of amino groups between all heated WPI solutions when measured by the OPA and TNBS methods, with lower levels being measured by the TNBS method than by the OPA method. These results demonstrate that the measurement of available amino groups by the OPA method is less impacted than by the TNBS method after heat-induced structural changes, arising from disulfide or sulfhydryl-disulfide bond-mediated aggregation of whey protein molecules.en
dc.description.sponsorshipDepartment of Agriculture, Food and the Marine, Ireland (Food Institutional Research Measure (FIRM) Initiative: Project Number 10/RD/OptiHydro/UCC/702)en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationMulcahy, E. M., Fargier-Lagrange, M., Mulvihill, D. M. and O'Mahony, J. A. (2017) 'Characterisation of heat-induced protein aggregation in whey protein isolate and the influence of aggregation on the availability of amino groups as measured by the ortho-phthaldialdehyde (OPA) and trinitrobenzenesulfonic acid (TNBS) methods', Food Chemistry, 229, pp. 66-74. doi:10.1016/j.foodchem.2017.01.155en
dc.identifier.doi10.1016/j.foodchem.2017.01.155
dc.identifier.endpage74en
dc.identifier.issn0308-8146
dc.identifier.journaltitleFood Chemistryen
dc.identifier.startpage66en
dc.identifier.urihttps://hdl.handle.net/10468/4467
dc.identifier.volume229en
dc.language.isoenen
dc.publisherElsevier Ltden
dc.rights© 2017 Elsevier B.V. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license.en
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en
dc.subjectWhey proteinen
dc.subjectDenaturationen
dc.subjectAggregationen
dc.subjectAmino groupsen
dc.subjectPhthaldialdehydeen
dc.subjectOPAen
dc.subjectTrinitrobenzenesulfonic aciden
dc.subjectTNBSen
dc.titleCharacterisation of heat-induced protein aggregation in whey protein isolate and the influence of aggregation on the availability of amino groups as measured by the ortho-phthaldialdehyde (OPA) and trinitrobenzenesulfonic acid (TNBS) methodsen
dc.typeArticle (peer-reviewed)en
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