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dc.contributor.authorKoontz, John L.en_US
dc.date.accessioned2014-03-14T20:09:19Z
dc.date.available2014-03-14T20:09:19Z
dc.date.issued2008-04-04en_US
dc.identifier.otheretd-04102008-194434en_US
dc.identifier.urihttp://hdl.handle.net/10919/26757
dc.description.abstractSynthetic antioxidants have traditionally been added directly to food products in a single initial dose to protect against oxidation of lipids and generation of free radicals. Natural antioxidants have been shown to undergo loss of activity and become prooxidants at high concentrations; therefore, a need exists to develop active packaging which can gradually deliver antioxidants in a controlled manner. The objectives of this research were to (1) form and characterize cyclodextrin inclusion complexes with the natural antioxidants, alpha-tocopherol and quercetin, (2) incorporate cyclodextrin inclusion complexes of natural antioxidants into linear low density polyethylene (LLDPE), and (3) measure the release kinetics of inclusion complexes of natural antioxidants from LLDPE into a model food system. Cyclodextrin inclusion complexes of alpha-tocopherol and quercetin were formed by the coprecipitation method and characterized in the solid state by NMR, IR spectroscopy, and thermal analyses. Solid inclusion complex products of alpha-tocopherol:beta-cyclodextrin and quercetin:gamma-cyclodextrin had molar ratios of 1.7:1 as determined by UV spectrophotometry, which were equivalent to 18.1% (w/w) alpha-tocopherol and 13.0% (w/w) quercetin. Free and cyclodextrin complexed antioxidant additives were compounded with a twin-screw mixer into two LLDPE resin types followed by compression molding into films. Release of alpha-tocopherol and quercetin from LLDPE films into coconut oil at 30 °C was quantified by HPLC during 4 weeks of storage. The total release of alpha-tocopherol after 4 weeks was 70% from the free form and 8% from the complexed form averaged across both LLDPE resins. The mechanism by which alpha-tocopherol was released was modified due to its encapsulation inside the beta-cyclodextrin cavity within the LLDPE matrix as indicated by its diffusion coefficient decreasing by two orders of magnitude. Molecular encapsulation of natural antioxidants using cyclodextrins may be used as a controlled release mechanism within polymer food packaging to gradually deliver an effective antioxidant concentration to a food product, thereby, limiting oxidation, maintaining nutritional quality, and extending shelf life.en_US
dc.publisherVirginia Techen_US
dc.relation.haspart01_DissertationBody_etd.pdfen_US
dc.relation.haspart00_FrontMatter_etd.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectalpha-tocopherolen_US
dc.subjectnatural antioxidanten_US
dc.subjectinclusion complexen_US
dc.subjectpackagingen_US
dc.subjectpolymeren_US
dc.subjectlinear low density polyethyleneen_US
dc.subjectcontrolled releaseen_US
dc.subjectcyclodextrinen_US
dc.subjectquercetinen_US
dc.titleControlled Release of Natural Antioxidants from Polymer Food Packaging by Molecular Encapsulation with Cyclodextrinsen_US
dc.typeDissertationen_US
dc.contributor.departmentFood Science and Technologyen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineFood Science and Technologyen_US
dc.contributor.committeechairMarcy, Joseph E.en_US
dc.contributor.committeememberLong, Timothy E.en_US
dc.contributor.committeememberDuncan, Susan E.en_US
dc.contributor.committeememberO'Keefe, Sean F.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04102008-194434/en_US
dc.date.sdate2008-04-10en_US
dc.date.rdate2009-04-23
dc.date.adate2008-04-23en_US


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