| 1. |
- Cozzolino, Carlo A., et al.
(författare)
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Microfibrillated cellulose and borax as mechanical, O-2-barrier, and surface-modulating agents of pullulan biocomposite coatings on BOPP
- 2016
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 143, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional composite coatings on bi-oriented polypropylene (BOPP) films were obtained using borax and microfibrillated cellulose (MFC) added to the main pullulan coating polymer. Spectroscopy analyses suggested that a first type of interaction occurred via hydrogen bonding between the C-6-OH group of pullulan and the hydroxyl groups of boric acid, while monodiol and didiol complexation represented a second mechanism. The deposition of the coatings yielded an increase in the elastic modulus of the entire plastic substrate (from similar to 2 GPa of the neat BOPP to similar to 3.1 GPa of the P/B+/MFC-coated BOPP). The addition of MFC yielded a decrease of both static and kinetic coefficients of friction of approximately 22% and 25%, respectively, as compared to the neat BOPP. All composite coatings dramatically increased the oxygen barrier performance of BOPP, especially under dry conditions. The deposition of the high hydrophilic coatings allowed to obtain highly wettable surfaces (water contact angle of similar to 18 degrees).
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| 2. |
- Gällstedt, Mikael, et al.
(författare)
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Production, Chemistry and Properties of Proteins
- 2011
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Ingår i: Biopolymers. - Chichester : John Wiley & Sons. - 9780470683415 - 9781119994312 ; , s. 107-132
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Hedenqvist, Mikael S., et al.
(författare)
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Extrusion of protein plastics
- 2017
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Ingår i: Abstracts of Papers of the American Chemical Society. - : American Chemical Society (ACS). - 0065-7727. ; 253
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
- Kuktaite, Ramune, et al.
(författare)
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Changes in the hierarchical protein polymer structure : Urea and temperature effects on wheat gluten films
- 2012
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:31, s. 11908-11914
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Tidskriftsartikel (refereegranskat)abstract
- Understanding bio-based protein polymer structures is important when designing new materials with desirable properties. Here the effect of urea on the wheat gluten (WG) protein structure in WG-urea films was investigated. Small-angle X-ray scattering indicated the formation of a hexagonal close-packed (HCP) hierarchical structure in the WG-urea materials. The HCP structure was influenced significantly by the urea concentration and processing conditions. The interdomain distance d I between the HCP scattering objects increased with increasing content of urea and the objects seemed to be oriented in the extrusion direction. Additionally, the effect of temperature on the HCP structure was studied and it was shown that at ≥55°C the HCP structure disappeared. Transmission electron microscopy revealed a rather denatured pattern of both HMW-glutenins and gliadins in the WG-urea films. The molecular packing of the WG protein polymer can be highly affected by an additive and the processing method used.
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| 6. |
- Kuktaite, Ramune, et al.
(författare)
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Gluten biopolymer and nanoclay-derived structures in wheat gluten-urea-clay composites
- 2014
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:6, s. 1439-1445
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Tidskriftsartikel (refereegranskat)abstract
- Here, we investigated the structure of natural montmorillonite (MMT) and modified Cloisite C15A (MMT pre-intercalated with a dimethyl-dehydrogenated tallow quaternary ammonium surfactant) nanoclays in the wheat gluten-urea matrix in order to obtain a nanocomposite with improved barrier and mechanical properties. Small-angle X-ray scattering indicated that the characteristic hexagonal closed packed structure of the wheat gluten-urea matrix was not found in the C15A system and existed only in the 3 and 5 wt % MMT composites. SAXS/WAXS, TGA, and water vapor/oxygen barrier properties indicated that the dispersion of the C15A clay was somewhat better than the natural MMT clay. Confocal laser scanning microscopy showed MMT clay clusters and C15A clay particles dispersed in the protein matrix, and these were preferentially oriented in the extrusion direction only at 5 wt % of the C15 clay. The water vapor/oxygen barrier properties were improved with the presence of clay. Independent of the clay content used, the stiffness decreased and the extensibility increased in the presence of C15A due to the surfactant induced changes on the protein. The opposite "more expected" clay effect (increasing stiffness and decreasing extensibility) was observed for the MMT composites.
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| 7. |
- Kuktaite, Ramune, et al.
(författare)
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Gluten Biopolymer and Nanoclay-Derived Structures in Wheat Gluten-Urea-Clay Composites: Relation to Barrier and Mechanical Properties
- 2014
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Ingår i: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:6, s. 1439-1445
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Tidskriftsartikel (refereegranskat)abstract
- Here, we investigated the structure of natural montmorillonite (MMT) and modified Cloisite C15A (MMT pre-intercalated with a dimethyl-dehydrogenated tallow quaternary ammonium surfactant) nanoclays in the wheat gluten-urea matrix in order to obtain a nanocomposite with improved barrier and mechanical properties. Small-angle X-ray scattering indicated that the characteristic hexagonal closed packed structure of the wheat gluten-urea matrix was not found in the CISA system and existed only in the 3 and 5 wt % MMT composites. SAXS/WAXS, TGA, and water vapor/oxygen barrier properties indicated that the dispersion of the C15A clay was somewhat better than the natural MMT clay. Confocal laser scanning microscopy showed MMT clay clusters and C15A clay particles dispersed in the protein matrix, and these were preferentially oriented in the extrusion direction only at 5 wt % of the CIS clay. The water vapor/oxygen barrier properties were improved with the presence of clay. Independent of the clay content used, the stiffness decreased and the extensibility increased in the presence of C15A due to the surfactant induced changes on the protein. The opposite "more expected" clay effect (increasing stiffness and decreasing extensibility) was observed for the MMT composites.
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| 8. |
- Rombouts, I., et al.
(författare)
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Crosslinks in wheat gluten films with hexagonal close-packed protein structures
- 2013
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Ingår i: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 51, s. 229-235
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Tidskriftsartikel (refereegranskat)abstract
- Wheat gluten/glycerol (WGG) films were extruded with aqueous ammonia/salicylic acid or urea to investigate the reactions contributing to their hexagonal close-packed protein structures and material properties. The addition of aqueous ammonia and salicylic acid increased the pH, which, in turn, increased the level of intermolecular disulfide and lanthionine cross-links in the WGG films. Increased protein cross-linking reactions resulted in higher material strength and tensile modulus. These cross-linking reactions and the resulting material properties were similar for WGG films with 7.5% and 10% aqueous ammonia. Added urea into WGG film partially degraded into cyanate and ammonium. Cyanate subsequently reacted with lysine and cysteine to ε-carbamyllysine and S-carbamylcysteine, respectively. Even though these reactions resulted in a more alkaline reaction environment, hereby favoring disulfide bond formation and decreasing protein extractability, they also prevented the involvement of cysteine and lysine in protein cross-linking. The alkylation of these reactive amino acids, together with the plasticizing effect of urea, led to lower material strength and elastic modulus with increasing levels of urea.
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| 9. |
- Rovera, Cesare, et al.
(författare)
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Water vapor barrier properties of wheat gluten/silica hybrid coatings on paperboard for food packaging applications
- 2020
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Ingår i: Food Packaging and Shelf Life. - : Elsevier Ltd. - 2214-2894. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Motivated by the increasing need for new solutions with less environmental impact, in this work we have investigated the benefits of depositing a wheat gluten (WG) coating on paperboard substrates intended for food packaging applications. To overcome the inherent moisture sensitivity of this protein, WG was combined with a silica network obtained by sol-gel chemistry. WG/silica hybrid coatings were characterized in terms of structural, thermal, morphological, surface, and water vapor barrier properties. Spectrometric analysis demonstrated that the organic and inorganic phases interacted primarily through hydrogen bonding. This was also supported by thermal experiments, which revealed a higher Tg measured for the hybrid materials with the higher silica content (114 ± 1 °C and 128 ± 2 °C, respectively) compared to the pure WG material (Tg = 89 ± 1 °C). Scanning electron microscopy showed that the surfaces of the coatings were very smooth, though the presence of pinholes, cracks, fractures, and voids was detected, especially for the silica-rich formulations. Upon deposition of the coatings, the wettability of the bare paperboard increased, as demonstrated by the lower water contact angle values. In addition, hybrid coatings exhibited a higher wettability over the pristine WG coating, which was due to a more intense spreading phenomenon. The deposition of the coatings led to a ∼ 4-fold reduction in water vapor transmission rate (WVTR ∼ 90 g m-2 24 h-1 at 23 °C and 65% relative humidity) of the specific cellulosic substrate tested in this work (WVTR ∼ 350 g m-2 24-1).
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| 10. |
- Türe, Hasan, et al.
(författare)
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Antimicrobial compression-moulded wheat gluten films containing potassium sorbate
- 2012
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Ingår i: Food Research International. - : Elsevier BV. - 0963-9969 .- 1873-7145. ; 45:1, s. 109-115
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial glycerol-plasticized wheat gluten (WG) films containing potassium sorbate (PS) were successfully produced by compression moulding; a thermoplastic process involving high temperature and high pressure. Antifungal properties of the films were tested against Aspergillus niger and Fusarium incarnatum by the agar diffusion assay. The results indicated that films containing more than 10 wt.% PS showed antimicrobial activity against A. niger while films containing 2.5 wt.% or more of PS showed antimicrobial activity against F. incarnatum. It was also found that when the film was exposed to an absorbing medium (the agar solution), most of the PS was released, an interesting feature for edible active packaging. Despite the loss, a very promising result was that, without seeding of spores, the films resisted microbial growth for at least one week when the films were left in the agar solution. X-ray diffraction and field emission scanning electron microscopy revealed that the PS crystals were dissolved in the wheat gluten material. In addition to the antimicrobial properties, dynamic mechanical, tensile, PS loss, water vapour transmission rate and oxygen permeability data also indicated that PS acted as a plasticiser in the wheat gluten film.
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| 11. |
- Ture, Hasan, et al.
(författare)
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Nanostructured Silica Wheat Gluten Hybrid Materials Prepared by Catalytic Sol-Gel Chemistry
- 2013
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 214:10, s. 1131-1139
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Tidskriftsartikel (refereegranskat)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 silica–protein 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.
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| 12. |
- Türe, Hasan, et al.
(författare)
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Properties of Wheat-Gluten/Montmorillonite Nanocomposite Films Obtained by a Solvent-Free Extrusion Process
- 2012
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1566-2543 .- 1572-8919 .- 1572-8900. ; :4, s. 1038-1045
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Tidskriftsartikel (refereegranskat)abstract
- This is, to our knowledge, the first study of wheat-gluten-based nanocomposite films prepared by a solvent-free extrusion process. Wheat gluten/montmorillonite nanocomposite films were obtained in a single screw-extruder using urea as a combined denaturant and plasticizer. The oxygen permeability and water vapor transmission rate of the films decreased by respectively factors of 1. 9 and 1. 3 when 5 wt.% clay was added. At the same time, the stiffness increased by a factor of 1. 5, without any critical loss of extensibility. Field emission scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray analysis indicated that the clay particles were layered mainly in the plane of the extruded film. It was possible to identify individual platelets/tactoids with FE-SEM and, together with findings from transmission electron microscopy, atomic force microscopy and X-ray diffraction, it was concluded that the clay existed as individual clay platelets, intercalated tactoids and agglomerates. Thermogravimetric analysis showed that the thermal stability of the extrudates was improved by the addition of clay.
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| 13. |
- Türe, Hasan, et al.
(författare)
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Protein network structure and properties of wheat gluten extrudates using a novel solvent-free approach with urea as a combined denaturant and plasticiser
- 2011
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 7:19, s. 9416-9423
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Tidskriftsartikel (refereegranskat)abstract
- This is, to our knowledge, the first success on solvent-free extrusion of wheat gluten (WG) into high quality films without using NaOH/salicylic acid. It was possible by using urea (concentrations: 10, 15 and 20 wt%) in the single screw-extruder process. Tensile testing, oxygen permeability, water vapor transmission rate, infrared spectroscopy (IR), confocal laser scanning microscopy (CLSM) and protein solubility were used to assess the properties of the extrudates. As the urea concentration increased, the strength and stiffness decreased while the extensibility increased. The oxygen permeability was low and increased, as did the water vapor transmission rate, with increasing urea concentration. The protein solubility of urea-containing films was found to be significantly lower than that of the native gluten and glycerol-plasticized WG extrudate. CLSM, together with the protein solubility, indicated that the urea films were aggregated/polymerized and IR spectroscopy revealed that these films contained a sizeable amount of beta-sheets with a high degree of hydrogen bonds associated with protein aggregation. The aggregation did not change with increasing urea concentration, which suggests that the changes in the mechanical and permeability properties were due to urea-induced plasticisation.
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| 14. |
- Türe, Hasan
(författare)
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Wheat Gluten -Based Materials and Composites: Extrusion, Casting and Antimicrobial Properties
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of bio-based polymers as packaging materials has gained much attention due to increasing environmental concerns regarding non-biodegradable petroleum-derived plastics. Wheat gluten (WG) is a valuable renewable resource for the production of bio-based materials because of its low price, biodegradability, good film-forming properties and good gas barrier properties under dry conditions. This study presents the processing and development of WG-based materials and composites.The first part presents a novel approach to obtain high quality WG films in a solvent-free extrusion process. Extrudability of WG was significantly improved by using urea and the films were flexible with remarkable barrier properties. Results indicated that urea-containing films were aggregated/polymerized and contained a considerable amount of b-sheet structure with a high degree of hydrogen bonding. Adding urea changed the protein structure, and it was found that urea seemed to work as a plasticiser, as observed by the way in which the barrier and mechanical properties changed with increasing urea concentration (Paper I).In the second part, wheat gluten/montmorillonite (WG/MMT) nanocomposite films were prepared in a solvent-free extrusion process with urea. The oxygen permeability (OP) and water vapor transmission rate (WVTR) of the films were lowered by the use of montmorillonite clay. At the same time, the stiffness of the films increased without any critical loss of extensibility and the thermal stability of the extrudates was improved by the addition of the clay. Results indicated that the clay particles were layered mainly in the plane of the extruded films and the clay existed as individual platelets, intercalated tactoids and agglomerates (Paper II).The third part describes the development of WG/silica hybrid materials obtained by the sol-gel process. The presence of silica constrained the WG component to such an extent that moisture-induced aggregation/denaturation was small. Results suggested that the constraint came from interactions between the silica and wheat gluten phases, mainly due to hydrogen bond interactions. A substantial improvement in the thermal properties was observed as the silica content increased. It was found that reduction of the moisture diffusivity in the presence of silica can be explained by the geometrical impedance imposed by the interpenetrating silica phase (Paper III).The fourth part focuses on thermoplastically produced antimicrobial wheat gluten materials. Antimicrobial WG films containing potassium sorbate (PS) were successfully produced by compression moulding. Films containing more than 10 wt.% PS showed antimicrobial activity against Aspergillus niger while films containing 2.5 wt.% or more PS showed antimicrobial activity against Fusarium incarnatum. It was observed that when no seeding with spores was adopted, the PS films, in contrast to the PS-free films, resisted antimicrobial growth for at least one week. It was also found that PS was dissolved in WG films and that when the films were exposed to an agar solution most of the PS was released. In addition to the antimicrobial properties, results also indicated that PS acted as a plasticiser in the WG films (Paper IV).
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| 15. |
- Türe, Hasan, et al.
(författare)
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Wheat-gluten/montmorillonite clay multilayer-coated paperboards with high barrier properties
- 2013
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Ingår i: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 51, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the oxygen-barrier properties of paperboards with a wheat gluten (WG)/montmorillonite clay (MMT) multilayer coating, in which MMT was sandwiched between two layers of WG. Urea was added to the WG to facilitate the coating procedure and the clay was applied as an aqueous dispersion. With a coating thickness of ~20μm, oxygen transmission rates were 8-10cm3/(m2dayatm) at 50% RH, which meant that the oxygen barrier was ca. 25 times better than that given by a single-layer WG-coated paperboard (uncoated paperboard showed infinite values). The water vapor transmission rate (WVTR) was 28-39g/(m2day) using a 50-0% RH gradient, which was 6- to 8-fold lower than the value for uncoated paperboard. Tensile tests revealed small, if any, mechanical effects when the paperboard was coated. A protein solubility analysis indicated that urea-containing WG films were slightly more intermolecularly cross-linked than urea-free WG films. X-ray diffraction revealed that the MMT layer consisted of unswollen tactoids similar to those observed in the MMT powder. The Cobb60 data showed that both WG and clay increased the water absorbency.
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