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Evaluation of chemical assays for determining hydroperoxides levels in oxidized lipids

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TitleInfo
Title
Evaluation of chemical assays for determining hydroperoxides levels in oxidized lipids
Name (type = personal)
NamePart (type = family)
Steltzer
NamePart (type = given)
Elah Tamar
NamePart (type = date)
1984-
DisplayForm
Elah Steltzer
Role
RoleTerm (authority = RULIB)
author
Name (type = personal)
NamePart (type = family)
Schaich
NamePart (type = given)
Karen M
DisplayForm
Karen M Schaich
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
chair
Name (type = personal)
NamePart (type = family)
HO
NamePart (type = given)
CHI-TANG
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CHI-TANG HO
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
internal member
Name (type = personal)
NamePart (type = family)
Frenkel
NamePart (type = given)
Chaim
DisplayForm
Chaim Frenkel
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
internal member
Name (type = corporate)
NamePart
Rutgers University
Role
RoleTerm (authority = RULIB)
degree grantor
Name (type = corporate)
NamePart
Graduate School - New Brunswick
Role
RoleTerm (authority = RULIB)
school
TypeOfResource
Text
Genre (authority = marcgt)
theses
OriginInfo
DateCreated (qualifier = exact)
2012
DateOther (qualifier = exact); (type = degree)
2012-05
Place
PlaceTerm (type = code)
xx
Language
LanguageTerm (authority = ISO639-2b); (type = code)
eng
Abstract (type = abstract)
This thesis re-evaluated current analyses for hydroperoxides, the first stable product of lipid oxidation. The objective was to compare linearity of response, accuracy, limits of detection, active concentration range, reproducibility, and required conditions and handling for six commonly-used hydroperoxide assays, using cumene (lipid-soluble) and tert-butyl (water-soluble) hydroperoxides as test standards; optimized procedures were then applied to oxidized methyl linoleate. Traditional iodometric titration method with thiosulfate is the most accurate assay chemically. It is stoichiometric, linear, and useful for high peroxide concentrations, but unclear endpoints limits sensitivity and many handling issues must be controlled to provide reproducible results. It is the only method providing absolute quantitation of hydroperoxides. PeroxySafeTM and PeroxoQuantTM commercial kits based on the xylenol orange assay detected nanomoles of hydroperoxides, but samples with more than trace levels of hydroperoxides (the usual case with foods) must be diluted extensively before analysis. Variation of reaction response varied with hydroperoxide structure is a major disadvantage for this assay, and the Fe3+-xylenol orange complex was readily bleached by excess hydroperoxide, thus reducing apparent hydroperoxide levels. Reaction stoichiometry cannot be determined due to proprietary reagents of unspecified concentration. The ferric thiocyanate method (chemical reaction or Cayman LPOTM kit) is extremely sensitive, detecting as low as 5 nanomoles, but the reaction stoichiometry varies with solvent and hydroperoxide structure and concentration. Fe3+-SCN complexes bleached at high hydroperoxide concentrations, causing underestimation of peroxide values. Extensive dilution of samples is thus required for analyses of lipid extracts from most foods. Due to these complications, xylenol orange and Fe3+-thiocyanate assays may be useful for monitoring changes of single materials over time or comparing extracts with comparable fatty acid composition, but they cannot determine absolute hydroperoxide concentrations. No optical assay tested matched peroxide values determined by iodometric assay. Finally, hydroperoxides oxidize triphenylphosphine selectively and stoichiometrically to triphenylphosphine oxide that can be detected and quantitated by HPLC, detecting as low as 5 picomoles of hydroperoxide. The reaction has promise, but needs further investigation before adoption. Results for all methods highlight the importance of excluding oxygen during the assays and understanding the correct concentration range for each assay.
Subject (authority = RUETD)
Topic
Food Science
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_4013
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
xi, 130 p. : ill.
Note (type = degree)
M.S.
Note (type = bibliography)
Includes bibliographical references
Note (type = statement of responsibility)
by Elah Tamar Steltzer
Subject (authority = ETD-LCSH)
Topic
Lipids--Research
Subject (authority = ETD-LCSH)
Topic
Peroxides
Identifier (type = hdl)
http://hdl.rutgers.edu/1782.1/rucore10001600001.ETD.000065269
RelatedItem (type = host)
TitleInfo
Title
Graduate School - New Brunswick Electronic Theses and Dissertations
Identifier (type = local)
rucore19991600001
Location
PhysicalLocation (authority = marcorg); (displayLabel = Rutgers, The State University of New Jersey)
NjNbRU
Identifier (type = doi)
doi:10.7282/T3Q81C1R
Genre (authority = ExL-Esploro)
ETD graduate
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Rights

RightsDeclaration (ID = rulibRdec0006)
The author owns the copyright to this work.
RightsHolder (type = personal)
Name
FamilyName
Steltzer
GivenName
Elah
Role
Copyright Holder
RightsEvent
Type
Permission or license
DateTime (encoding = w3cdtf); (qualifier = exact); (point = start)
2012-04-20 15:09:21
AssociatedEntity
Name
Elah Steltzer
Role
Copyright holder
Affiliation
Rutgers University. Graduate School - New Brunswick
AssociatedObject
Type
License
Name
Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.
Copyright
Status
Copyright protected
Availability
Status
Open
Reason
Permission or license
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