Oxygen-reducing enzymes in coatings and films for active packaging
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Oxygen scavengers are used in active packages to protect the food against deteriorative oxidation processes. The aim of this work was to investigate the possibilities to produce oxygen-scavenging packaging materials based on oxygen-reducing enzymes. The enzymes were incorporated into a dispersion coating formulation applied onto a food-packaging board using conventional laboratory coating techniques.
Various enzymes were used: a glucose oxidase, an oxalate oxidase and three laccases originating from different organisms. All of the enzymes were successfully incorporated into a coating layer and could be reactivated after drying. For at least two of the enzymes, re-activation was possible not only by using liquid water but also by using water vapour. Re-activation of the glucose oxidase and a laccase required relative humidities of greater than 75% and greater than 92%, respectively.
Catalytic reduction of oxygen gas by glucose oxidase was promoted by creating an open structure through addition of clay to the coating at a level above the critical pigment volume concentration. Migration of the enzyme and the substrate was reduced by adding an extrusion-coated liner of polypropylene on top of the coating.
For the laccase-catalysed reduction of oxygen it was possible to use lignin derivatives as substrates for the enzymatic reaction. The laccase-catalysed reaction created a polymeric network by cross-linking of lignin-based entities, which resulted in increased stiffness and increased water-resistance of biopolymer films. The laccases were also investigated with regard to their potential to function as oxygen scavengers at low temperatures. At 7°C all three laccases retained more than 20% of the activity they had at room temperature (25°C), which suggests that the system is also useful for packaging of refrigerated food.
Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2013. , 91 p.
Karlstad University Studies, ISSN 1403-8099 ; 2013:38
Active packaging, food packaging, oxygen scavengers, oxygen-reducing enzymes, dispersion coating, biopolymers
Research subject Chemical Engineering
IdentifiersURN: urn:nbn:se:kau:diva-28749ISBN: 978-91-7063-516-8OAI: oai:DiVA.org:kau-28749DiVA: diva2:643381
2013-10-18, 9C204, Rejmersalen, Karlstad, 10:15 (English)
Lagaron, Jose M., Professor
Järnström, Lars, ProfessorJohansson, Caisa, UniversitetslektorJönsson, Leif J., Professor
List of papers