Tesis por compendio / This PhD dissertation thesis has been focus on the development and characterization of
antimicrobial packaging films based on the incorporation in the polymer matrix or on
the attachment to the film surface of naturally occurring antimicrobial compounds with
the purpose of inhibiting the proliferation of microorganisms and extend the microbiological
shelf life of packaged food products.
The studied active films are based on the use of ethylene vinyl copolymers (EVOH) containing
29% (EVOH29) or 44% (EVOH44) molar percentage of ethylene as polymeric vehicle
for the incorporation of several antimicrobial compounds -oregano essential oil (OEO),
citral, ethyl lauroyl arginate (LAE), epsilon-polylysine (EPL), green tea extract (GTE) and
lysozyme. These antimicrobial agents have been incorporated in the film-forming solution
or immobilized to the film surface by covalent bonding.
Prior to the preparation of the active films, the antimicrobial activity of the selected compounds
against selected microorganism was demonstrated, confirming that they could be
good candidates to be used as preservatives for active food packaging applications, and
an alternative to synthetic additives. The effect of the incorporation of the antimicrobial
agents on relevant functional properties of the developed EVOH films was studied.
In general, the polymer properties as materials for food packaging were not relevantly
affected.
In order to evaluate the potential of EVOH matrices as sustain release systems of active
compounds, the release kinetics of the active compounds from the film to different media
was evaluated; for that the agent release rate and extend into food simulants was
monitored, and it was concluded that the agent concentration, release temperature, type
of EVOH, interaction of EVOH with the food simulant, and the solubility of the active
compound in the release media were the main controlling factors.
EVOH matrices have also shown good properties to be used for the attachment of active
molecules. In this regard, lysozyme was successfully immobilized on the film surface of
EVOH.
Several experiments were conducted to determine the antimicrobial properties of the
resulting films in vitro against different microorganisms responsible for foodborne illness
and in vivo with real foods –minimally-process salad, infant milk, surimi sticks and chicken
stock- to enhance their preservation. All the materials presented a strong in vitro antimicrobial
activity. Although the results obtained through in vivo tests showed activity
reductions caused by food matrix effects, all materials presented significant microbial
inhibition and, therefore, great potential to be used in the design of active food packaging.
They can be applied as an inner coating of the packaging structure, releasing the active
agent or acting by direct contact, producing a great protection against contamination
with a prolongation of the microbiological food shelf life. / Muriel Galet, V. (2015). Novel antimicrobial films based on ethylene-vinyl alcohol copolymers for food packaging application [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48522 / TESIS / Premios Extraordinarios de tesis doctorales / Compendio
| Identifer | oai:union.ndltd.org:upv.es/oai:riunet.upv.es:10251/48522 |
| Date | 16 January 2016 |
| Creators | Muriel Galet, Virginia |
| Contributors | Gavara Clemente, Rafael José, Hernandez Muñoz, Maria Pilar, Universitat Politècnica de València. Instituto Universitario de Ingeniería de Alimentos para el Desarrollo - Institut Universitari d'Enginyeria d'Aliments per al Desenvolupament |
| Publisher | Universitat Politècnica de València |
| Source Sets | Universitat Politècnica de València |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/acceptedVersion |
| Rights | http://rightsstatements.org/vocab/InC/1.0/, info:eu-repo/semantics/openAccess |
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