Packaging‐related properties of protein‐ and chitosan‐coated paper
ABSTRACT The mechanical and gas-barrier properties of paper and paperboard coated with chitosan–acetic acid salt (chitosan), whey protein isolate, whey protein concentrate and wheat gluten protein were studied. Paper sheets were solution-coated using a hand applicator. In addition, bi-layer composites of wheat gluten and paper or paperboard were produced by compression moulding, and the chitosan solution was also applied on paperboard using curtain coating. Young's modulus, fracture stress, fracture strain, tearing strength, air permeance and oxygen permeability were assessed. The mechanical and air permeance measurements of solution-coated paper showed that chitosan was the most effective coating on a coat weight basis. This was due to its high viscosity, which limited the degree of penetration into the paper. The proteins, however, also enhanced the strength and toughness of the paper. Compression-moulded wheat gluten/paper or paperboard, as well as curtain-coated chitosan paperboard laminates, showed oxygen barrier properties comparable to those of paper and paperboard coated with commercial barrier materials. None of the composites could be delaminated without fibre rupture, indicating good adhesion between the coatings and the substrates. Copyright © 2005 John Wiley & Sons, Ltd.
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ABSTRACT: Bionanocomposites were developed by casting/evaporation of wheat gluten (WG), cellulose nanocrystals (CNC), and TiO2 nanoparticles. The effect of addition of different percentages of CNC, and TiO2 on tensile strength (TS), Young's modulus and water sensitivity was studied. A significant improvement in the studied properties is observed when 7.5% CNC and 0.6% TiO2 is added to WG. WG/CNC 7.5%/0.6% TiO2 blend suspension was chosen to coat commercial packaging unbleached kraft paper sheets via 1, 2 and 3 coating layers. A significant enhancement of 56% and 53% in breaking length and burst index, respectively, was achieved for 3 layers coated paper. The antimicrobial activity of the coated papers, against Saccharomyces cervisiae, Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus, was investigated and expressed in terms of reduction % of surviving number (CFU) of the tested organisms. More than 98.5% reduction in CFU was observed against the organisms compared to TiO2-free coated paper. Copyright © 2015 Elsevier Ltd. All rights reserved.Carbohydrate Polymers 06/2015; 124. DOI:10.1016/j.carbpol.2015.01.076 · 3.92 Impact Factor
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ABSTRACT: The increasing need to improve end-user specifications of paper encourages studying of coating bagasse-based paper with chitosan and gelatin in order to acheive good mechanical and barrier properties. The effect of different concentrations of gelatin (0.5-2.5%) on mechanical properties (breaking length, burst index and tear index) of bagasse paper sheets was studied. Also, paper sheets were coated by impregnation in different concentrations of chitosan solution (0.2-2%). Paper coatings using coating blends from 2% gelatin solution containing 0.5% glycerol and 1% chitosan were studied in ratios of 1:0, 3:1, 1:1, 1:3 and 0:1 gelatin/glycerol: chitosan. Air permeability and mechanical properties of coated paper was studied. Scanning electron microscope study indicates that the distribution of gelatin/glycerol/ chitosan onto the coated paper is uniform. In general, both water-soluble gelatin and chitosan coatings had a positive impact on the final properties of the coated paper.Nordic Pulp and Paper Research Journal 06/2014; 29(4):741. · 0.68 Impact Factor
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ABSTRACT: The main physicochemical properties of nanostructured silica/wheat gluten hybrid composites are presented. The extraction experiments suggest that the protein phase is intimately encased within the silica matrix, with silicaprotein interactions driven by hydrogen bonding, as indicated by IR spectra. Spectroscopic results also show that silica induces a higher degree of constraint of the wheat gluten matrix, despite less aggregation. Moisture diffusion properties of the hybrid materials are investigated by a combined desorption/sorption approach. While the reduction of the moisture diffusivity in the presence of silica can be described by the geometrical impedance of a sintered porous solid, a time-dependent relaxation/restructuring of the composite apparently occurs during the sorption-desorption cycle.Macromolecular Chemistry and Physics 05/2013; 214(10). DOI:10.1002/macp.201200646 · 2.45 Impact Factor