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Xylan-based biodegradable and wheat gluten-based antimicrobial film production

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2008
Karamanlıoğlu, Mehlika
In the first part of the study, birchwood xylan-lignin film formation was studied. After film forming effect of lignin on pure birchwood xylan was demonstrated, the minimum lignin concentration necessary to form films was determined as 1.1% (lignin/xylan). So, it was determined that keeping about one percent lignin in xylan (w/w) was sufficient for film formation. Biodegradability of the lignin-birchwood xylan composite films was investigated enzymatically using 0.21 U / ml xylanase in an accelerated test. All the films containing lignin were hydrolyzed by xylanase showing biodegradability of the films. Colors of the birchwood xylan-lignin composite films containing different lignin concentrations were compared. Deviations of the color from the reference color were similar between the films. In the second part of the study, photocatalytic antimicrobial film production was investigated on wheat gluten-based films. In order to produce antimicrobial films, wheat gluten films were coated with a semiconductor, titanium dioxide (TiO2), applying different procedures. Coated films were illuminated and photocatalytical inactivation of Escherichia coli on films were determined by antimicrobial tests. The coating procedure in which titanium dioxide (TiO2) was produced from titanium tetraisopropoxide (TTIP) in aqueous-nitric acid and aqueous-hydrochloric acid solutions gave the best antimicrobial result but the films turned out to be deformed and brittle. Spreading TiO2 sol-gel on semi-dried wheat gluten films resulted in flexible and undeformed films having about 40% antimicrobial activity.