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dc.contributor.authorKoontz, John L.en
dc.date.accessioned2014-03-14T20:09:19Zen
dc.date.available2014-03-14T20:09:19Zen
dc.date.issued2008-04-04en
dc.identifier.otheretd-04102008-194434en
dc.identifier.urihttp://hdl.handle.net/10919/26757en
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
dc.publisherVirginia Techen
dc.relation.haspart01_DissertationBody_etd.pdfen
dc.relation.haspart00_FrontMatter_etd.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectalpha-tocopherolen
dc.subjectnatural antioxidanten
dc.subjectinclusion complexen
dc.subjectpackagingen
dc.subjectpolymeren
dc.subjectlinear low density polyethyleneen
dc.subjectcontrolled releaseen
dc.subjectcyclodextrinen
dc.subjectquercetinen
dc.titleControlled Release of Natural Antioxidants from Polymer Food Packaging by Molecular Encapsulation with Cyclodextrinsen
dc.typeDissertationen
dc.contributor.departmentFood Science and Technologyen
dc.description.degreePh. D.en
thesis.degree.namePh. D.en
thesis.degree.leveldoctoralen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineFood Science and Technologyen
dc.contributor.committeechairMarcy, Joseph E.en
dc.contributor.committeememberLong, Timothy E.en
dc.contributor.committeememberDuncan, Susan E.en
dc.contributor.committeememberO'Keefe, Sean F.en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04102008-194434/en
dc.date.sdate2008-04-10en
dc.date.rdate2009-04-23en
dc.date.adate2008-04-23en


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