Master Degree / Yüksek Lisans Tezleri

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Author: search.filters.author.Bayramoğlu, BesteSubject: search.filters.subject.Food packaging

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  • Master Thesis
    Structure and Gas Transmission Properties of Surface Modified Food Packaging Materials by Layer-By Assembly
    (Izmir Institute of Technology, 2019) Koca, Nazan; Bayramoğlu, Beste; Bayramoğlu, Beste; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, two different LbL coatings of chicken egg white lysozyme (LZ) (0.2 % w/v)-gum arabic (GA) (0.2 % w/v) and lysozyme (LZ) (0.2 % w/v)-iota carrageenan (IC) (0.2 % w/v) were investigated as a potential agent in the fabricaton of surfacemodified food packaging materials with improved gas barrier properties. The effects of solution pH, adsorption time, number of layers, and inclusion of drying step in between deposition steps on multilayer formation were explored for both LbL coatings seperately. Film growth was monitored up to 10 layers by UV-Vis spectrometry and Surface Plasmon Resonance (SPR), which allows for in situ observation of the multilayer formation. The LbL coatings were characterized by AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy). The oxygen and water vapor transmission rates of the coatings (assembled on corona treated polypropylene (PP) films) were also measured. The most successful LbL assembly was obtained at pH 7-7 combination, with 20 minutes adsorption time and with intermediate drying steps for both (LZ-GA and LZ-IC) LbL coatings. For both LbL coating, both the UV-Vis and SPR measurements showed the similar zig-zag trend; i.e. desorption of some of the pre-adsorbed LZ from the interface with the deposition of GA (or IC) on it, probably due to formation of soluble complexes between them. The importance of intermediate drying steps was established by UV-Vis, AFM and gas transmission rate measurements. The absence of intermediate drying caused a reduction in total mass deposited and the gas barrier properties of the coatings.