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International Journal of Polymer Science
Volume 2017, Article ID 1846031, 6 pages
https://doi.org/10.1155/2017/1846031
Research Article

UV Radiation Induced Cross-Linking of Whey Protein Isolate-Based Films

1Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Strasse 35, 85354 Freising, Germany
2Chair for Food Packaging Technology, Technische Universität München, Weihenstephaner Steig 22, 85354 Freising, Germany

Correspondence should be addressed to Markus Schmid; ed.refohnuarf.vvi@dimhcs.sukram

Received 11 April 2017; Accepted 9 May 2017; Published 4 June 2017

Academic Editor: Raffaele Cucciniello

Copyright © 2017 Markus Schmid et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Casted whey protein films exposed to ultraviolet irradiation were analyzed for their cross-linking properties and mechanical and barrier performance. Expected mechanical and barrier improvements are discussed with regard to quantification of the cross-linking in the UV-treated whey protein films. Swelling tests were used to determine the degree of swelling, degree of cross-linking, and cross-linking density. When the UV radiation dosage was raised, a significant increase of the tensile strength as well as an increase in Young’s modulus was observed. No significant changes in water vapor and oxygen barrier properties between the UV-treated films and an untreated reference sample could be observed. The cross-linking density and the degree of cross-linking significantly increased due to UV radiation. Combined results indicate a disordered protein network in cast films showing locally free volume and therefore only minor mechanical and barrier improvements.