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Oxygen scavenging enzymes in coatings: Effect of coating procedures on enzyme activity
Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre.
Department of Chemistry, Umeå University.
Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre.ORCID-id: 0000-0002-1256-1708
2011 (Engelska)Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, nr 2, s. 197-204Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The oxygen content in food packaging may be reduced by attaching oxygen scavengers to the packaging material. The critical parameters that determine the oxygen-scavenging ability of an enzyme-based coating i.e. pH, heat and coating color formulation were evaluated. Glucose oxidase, catalase and glucose were added to latex dispersions in the preparation of the coating colors. The enzymes were entrapped in the coating layers after coating and drying. The clay concentration and drying conditions were varied and the enzymatic activity of the coated layer was evaluated. The need for a pH-buffered system was also studied and the results indicated that, when using a carboxylated latex of a standard coating grade, a buffered system was not needed. A rapid drying at a high temperature was preferred over a slow drying at a low temperature in order to prevent pre-oxidation of the substrate in the wet coating color. The scavenging capacity of the coating was dependent on the amount of substrate for the enzyme reaction left after complete drying. The concentration of clay in the coating formulation was shown to have a marked impact on the oxygen-scavenging ability of the coated layer. The enzyme activity was increased by the addition of clay up to a pigment volume concentration (PVC) of ca. 10%. At higher concentrations of clay, the enzyme activity decreased until the critical pigment volume concentration (CPVC) was reached, probably due to the prevention of diffusion of oxygen and consumption of glucose in the coating process before the layer was completely dried. Further additions of clay above the CPVC resulted in an increased enzyme activity, probably due to the creation of a porous structure.

Ort, förlag, år, upplaga, sidor
Stockholm: Mittuniversitetet , 2011. Vol. 26, nr 2, s. 197-204
Nyckelord [en]
Enzyme activity, Oxidation, Oxygen, Packaging materials, Scavenging
Nationell ämneskategori
Kemiteknik Kemi Industriell bioteknik
Identifikatorer
URN: urn:nbn:se:kau:diva-15069ISI: 000291334400004OAI: oai:DiVA.org:kau-15069DiVA, id: diva2:558159
Tillgänglig från: 2012-10-26 Skapad: 2012-10-02 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
Ingår i avhandling
1. Oxygen-reducing enzymes in coatings and films for active packaging
Öppna denna publikation i ny flik eller fönster >>Oxygen-reducing enzymes in coatings and films for active packaging
2013 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

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.

Ort, förlag, år, upplaga, sidor
Karlstad: Karlstads universitet, 2013. s. 91
Serie
Karlstad University Studies, ISSN 1403-8099 ; 2013:38
Nyckelord
Active packaging, food packaging, oxygen scavengers, oxygen-reducing enzymes, dispersion coating, biopolymers
Nationell ämneskategori
Kemiteknik
Forskningsämne
Kemiteknik
Identifikatorer
urn:nbn:se:kau:diva-28749 (URN)978-91-7063-516-8 (ISBN)
Disputation
2013-10-18, 9C204, Rejmersalen, Karlstad, 10:15 (Engelska)
Opponent
Handledare
Tillgänglig från: 2013-09-27 Skapad: 2013-08-27 Senast uppdaterad: 2014-10-27Bibliografiskt granskad

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Johansson, KristinJärnström, Lars

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