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dc.contributor.authorChan, Yuk Man
dc.contributor.authorCheng, Nga Kwan
dc.contributor.authorNigam, Poonam Singh
dc.contributor.authorOwusu-Apenten, Richard K.
dc.date.accessioned2019-02-25T14:58:02Z
dc.date.available2019-02-25T14:58:02Z
dc.date.issued2016-06-22
dc.identifier.citationChan, Y. M., Cheng, N. K., Nigam, P. S., & Owusu-Apenten, R. (2016). Effect of pH on the Radical Quenching Capacity of Tea Infusions Using the ABTS• Assay. Journal of Applied Life Sciences International, 6(2), 1-8.en_US
dc.identifier.doi10.9734/JALSI/2016/27235
dc.identifier.urihttp://hdl.handle.net/10034/621910
dc.description.abstractAims: The aims of this study were to assess the impact of pH on the free radical quenching activity of tea infusions using a modified 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay and three antioxidant compounds as reference. Study Design: In-vitro method. Place and Duration of Study: Faculty of Life and Health Science, School of Biomedical Sciences, Ulster University, UK. From Sept 2014 and May 2016. Methodology: Free radical quenching capacity of tea (Earl grey, black tea, Ceylon tea, & green tea) infusions were investigated using persulfate activated ABTS with acetate buffer (pH 4.5) or phosphate buffer saline (pH 7.0) as solvent. Tests were performed using 96-well microplates, 20 µl of sample and 280 µl of ABTS reagent, and calibrated using ascorbic acid, trolox or gallic acid as reference antioxidants. Results: Gallic acid free radical quenching was pH dependent and unsuitable as reference. The free radical quenching capacity of trolox and ascorbic acid was not significantly different at pH 4.5 and pH 7.0. The radical quenching capacity of tea infusions expressed as Trolox Equivalent Antioxidant Capacity (TEAC) or Ascorbic Acid Equivalent Antioxidant Capacity (AAEAC) was greater by 50-300% at pH 7 compared to pH 4.5. Conclusion: The modified ABTS assay is suitable for examining the influence of pH on free radical quenching ability of tea samples. Gallic acid was not a suitable reference compound. The radical quenching capacity of tea infusions increases with rising pH.en_US
dc.language.isoenen_US
dc.publisherSciencedomain Internationalen_US
dc.relation.urlhttp://www.sciencedomain.org/index.php?/abstract/15117en_US
dc.rightsAttribution-NoDerivatives 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by-nd/4.0/en_US
dc.subjectRadical quenchingen_US
dc.subjectABTSen_US
dc.subjectteaen_US
dc.subjectgallic aciden_US
dc.subjectascorbic aciden_US
dc.subjectTEAC valueen_US
dc.titleEffect of pH on the Radical Quenching Capacity of Tea Infusions Using the ABTS•+ Assayen_US
dc.typeArticleen_US
dc.identifier.eissn2394-1103
dc.contributor.departmentUniversity of Chester, University of Ulsteren_US
dc.identifier.journalJournal of Applied Life Sciences Internationalen_US
dc.date.accepted2016-06-16
or.grant.openaccessYesen_US
rioxxterms.funderNAen_US
rioxxterms.identifier.projectNAen_US
rioxxterms.versionVoRen_US
rioxxterms.licenseref.startdate2016-06-16
refterms.dateFCD2019-02-13T09:37:38Z
refterms.versionFCDEVoR
refterms.dateFOA2019-02-25T14:58:03Z


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