| 1. |
- Kuktaite, Ramune, et al.
(author)
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Monitoring Nanostructure Dynamics and Polymerization in Glycerol Plasticized Wheat Gliadin and Glutenin Films : Relation to Mechanical Properties
- 2016
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In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:6, s. 2998-3007
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Journal article (peer-reviewed)abstract
- Gliadin and glutenin proteins with 10, 20, 30 and 40% of glycerol were compression molded into films (130 °C) and evaluated for protein polymerization, β-sheet structure and nano-structural morphology. Here, for the first time we show how different amounts of glycerol impact the nano-structure and functional properties of the gliadin and glutenin films. Most polymerized protein was found in the gliadin films with 20 and 30% glycerol, and in all the glutenin films (except 10%), by RP-HPLC. A β-sheet-rich protein structure was found to be high in the 10 and 20% glycerol gliadin films, and in the 20 and 30% glycerol glutenin films by FT-IR. Glycerol content of 20, 30 and 40% impacted the nano-structural morphology of the gliadin glycerol films observed by SAXS, and to a limited extent for 10 and 20% glycerol gliadin films revealed by WAXS. No ordered nano-structure was found for the glutenin glycerol films. The 20%, 30% and 40% glycerol films were the most tunable for specific mechanical properties. For the highest stiffness and strength, the 10% glycerol protein films were the best choice.
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| 2. |
- Muneer, Faraz, et al.
(author)
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Innovative Gliadin/Glutenin and Modified Potato Starch Green Composites : Chemistry, Structure, and Functionality Induced by Processing
- 2016
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In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:12, s. 6332-6343
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Journal article (peer-reviewed)abstract
- In this study, we combined two wheat proteins, gliadin (Gli)/glutenin (GT), and modified potato starch (MPS) into composites using extrusion. In the Gli/GT MPS composites, we studied the structural dynamics of proteins and starch, protein starch interactions, protein properties, and composite morphology in relation to mechanical and barrier properties. Materials with different ratios of Gli/GT and MPS were extruded using either glycerol or glycerol water at 110 and 130 degrees C. For the first time, a hierarchical hexagonal structure of Gli proteins was observed in Gli MPS composite at both extrusion temperatures. The higher temperature (130 degrees C) induced a higher degree of protein cross-links, an increase in the polymer size, and formation of beta-sheets compared to 110 degrees C. The combination of plasticizers (glycerol and water) favored a micro-structural morphology with improved gelatinization of starch, processability, as well as strength, stiffness, and extensibility of GT MPS composites. The highest amount of the oxidized proteins was observed in the samples with the highest protein content and at high extrusion temperature. The Gli- and GT MPS (30/70) samples showed promising oxygen barrier properties under ambient testing conditions. These findings provide in-depth information for tailoring the structural functional relationship of the Gli/GT-potato starch composites for their promising use in designing various green materials.
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| 3. |
- Rasheed, Faiza, et al.
(author)
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The use of plants as a "green factory" to produce high strength gluten-based materials
- 2016
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In: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 18:9, s. 2782-2792
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Journal article (peer-reviewed)abstract
- The aim of the present study was to develop an understanding of how wheat plants can be used as a "green factory" by the modulation of genotype (G) and environmental (E) interactions to fine-tune the structure and increase the strength of gluten based materials. Two wheat genotypes (5 + 10 and 2 + 12) were grown under four nitrogen and two temperature regimes to obtain gluten of various characteristics. Protein microstructure morphology revealed by confocal laser scanning microscopy suggested a higher polymerisation of proteins in glycerol plasticized films from the 5 + 10 compared to the 2 + 12 genotype. Also, films with the highest Young's modulus and maximum stress were obtained from the 5 + 10 genotype, which might be explained by the higher number of cysteine residues and consequently more disulphide crosslinks in this genotype compared to the 2 + 12 one. The presence of two nano-scaled morphologies, hexagonal and lamellar structures and their internal relations were found to be of relevance for formation of beta-sheets and also to be related to performance (strength) of the material. Thus, plants could be used as a "green factory", avoiding the use of chemicals, to tune the tensile properties of the materials. Structural properties such as relatively low protein aggregation, high beta-sheet content and a high hexagonal to lamellar structural ratio at the nano-scale were found to yield films with high stiffness and strength.
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| 4. |
- Gallstedt, Mikael, et al.
(author)
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Film Extrusion of Crambe abyssinica/Wheat Gluten Blends
- 2017
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In: Journal of Visualized Experiments. - : JOURNAL OF VISUALIZED EXPERIMENTS. - 1940-087X. ; :119
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Journal article (peer-reviewed)abstract
- Crambe abyssinica is a plant with potential for use in industrial (non-food) plant oil production. The side stream from this oil production is a high-protein crambe meal that has limited value, as it is not fit for food or feed use. However, it contains proteins that could potentially make it a suitable raw material for higher-value products. The purpose of this study was to find methods of making this side stream into extruded films, showing that products with a higher value can be produced. The study mainly considered the development of material compositions and methods of preparing and extruding the material. Wheat gluten was added as a supportive protein matrix material, together with glycerol as a plasticizer and urea as a denaturant. The extrudate was evaluated with respect to mechanical (tensile testing) and oxygen barrier properties, and the extrudate structure was revealed visually and by scanning electron microscopy. A denser, more homogeneous material had a lower oxygen transmission rate, higher strength, and higher extensibility. The most homogeneous films were made at an extruder die temperature of 125-130 degrees C. It is shown here that a film can be extruded with promising mechanical and oxygen barrier properties, the latter especially after a final compression molding step.
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| 5. |
- Hedenqvist, Mikael S., et al.
(author)
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Extrusion of protein plastics
- 2017
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In: Abstracts of Papers of the American Chemical Society. - : American Chemical Society (ACS). - 0065-7727. ; 253
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Journal article (other academic/artistic)
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| 6. |
- Moyassari, Ali, et al.
(author)
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First-principle simulations of electronic structure in semicrystalline polyethylene
- 2017
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In: Journal of Chemical Physics. - : American Institute of Physics (AIP). - 0021-9606 .- 1089-7690. ; 146:20
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Journal article (peer-reviewed)abstract
- In order to increase our fundamental knowledge about high-voltage cable insulation materials, realistic polyethylene (PE) structures, generated with a novel molecular modeling strategy, have been analyzed using first principle electronic structure simulations. The PE structures were constructed by first generating atomistic PE configurations with an off-lattice Monte Carlo method and then equilibrating the structures at the desired temperature and pressure using molecular dynamics simulations. Semicrystalline, fully crystalline and fully amorphous PE, in some cases including crosslinks and short-chain branches, were analyzed. The modeled PE had a structure in agreement with established experimental data. Linear-scaling density functional theory (LS-DFT) was used to examine the electronic structure (e.g., spatial distribution of molecular orbitals, bandgaps and mobility edges) on all the materials, whereas conventional DFT was used to validate the LS-DFT results on small systems. When hybrid functionals were used, the simulated bandgaps were close to the experimental values. The localization of valence and conduction band states was demonstrated. The localized states in the conduction band were primarily found in the free volume (result of gauche conformations) present in the amorphous regions. For branched and crosslinked structures, the localized electronic states closest to the valence band edge were positioned at branches and crosslinks, respectively. At 0 K, the activation energy for transport was lower for holes than for electrons. However, at room temperature, the effective activation energy was very low (similar to 0.1 eV) for both holes and electrons, which indicates that the mobility will be relatively high even belowthe mobility edges and suggests that charge carriers can be hot carriers above the mobility edges in the presence of a high electrical field.
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| 7. |
- Muneer, Faraz, et al.
(author)
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Impact of pH Modification on Protein Polymerization and Structure-Function Relationships in Potato Protein and Wheat Gluten Composites
- 2019
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In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:1
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Journal article (peer-reviewed)abstract
- Wheat gluten (WG) and potato protein (PP) were modified to a basic pH by NaOH to impact macromolecular and structural properties. Films were processed by compression molding (at 130 and 150 degrees C) of WG, PP, their chemically modified versions (MWG, MPP) and of their blends in different ratios to study the impact of chemical modification on structure, processing and tensile properties. The modification changed the molecular and secondary structure of both protein powders, through unfolding and re-polymerization, resulting in less cross-linked proteins. The beta-sheet formation due to NaOH modification increased for WG and decreased for PP. Processing resulted in cross-linking of the proteins, shown by a decrease in extractability; to a higher degree for WG than for PP, despite higher beta-sheet content in PP. Compression molding of MPP resulted in an increase in protein cross-linking and improved maximum stress and extensibility as compared to PP at 130 degrees C. The highest degree of cross-linking with improved maximum stress and extensibility was found for WG/MPP blends compared to WG/PP and MWG/MPP at 130 degrees C. To conclude, chemical modification of PP changed the protein structures produced under harsh industrial conditions and made the protein more reactive and attractive for use in bio-based materials processing, no such positive gains were seen for WG.
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| 8. |
- Muneer, Faraz, et al.
(author)
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Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties
- 2015
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 16:3, s. 695-705
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Journal article (peer-reviewed)abstract
- In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130 °C. The nanomorphology of the composites showed the MPS having semicrystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by small-angle X-ray scattering and a B-type crystal structure observed by wide-angle X-ray scattering analysis. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130 °C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130 °C versus 110 °C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110 °C) and a decrease in both E-modulus and maximum stress at 110 and 130 °C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.
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| 9. |
- Muneer, Faraz, et al.
(author)
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The impact of newly produced protein and dietary fiber rich fractions of yellow pea (Pisum sativum L.) on the structure and mechanical properties of pasta-like sheets
- 2018
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In: Food Research International. - : Elsevier. - 0963-9969 .- 1873-7145. ; 106, s. 607-618
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Journal article (peer-reviewed)abstract
- Two fractions from pea (Pisum sativum L.), protein isolate (PPI) and dietary fiber (PF), were newly produced by extraction-fractionation method and characterized in terms of particle size distribution and structural morphology using SEM. The newly produced PPI and PF fractions were processed into pasta-like sheets with varying protein to fiber ratios (100/0, 90/10, 80/20, 70/30 and 50/50, respectively) using high temperature compression molding. We studied protein polymerization, molecular structure and protein-fiber interactions, as well as mechanical performance and cooking characteristics of processed PPI-PF blends. Bi-modal particle size distribution and chemical composition of the PPI and PF fractions influenced significantly the physicochemical properties of the pasta-like sheets. Polymerization was most pronounced for the 100 PPI, 90/10 and 80/20 PPI-PF samples as studied by SE-HPLC, and polymerization decreased with addition of the PF fraction. The mechanical properties, as strength and extensibility, were likewise the highest for the 100 PPI and 90/10 PPI-PF blends, while the E-modulus was similar for all the studied blends (around 38 MPa). The extensibility decreased with the increasing amount of PF in the blend. The highest amounts of beta-sheets were found in the pasta-like sheets with high amounts of PPI (100, 90 and 80%), by FT-IR. An increase in PF fraction in the blend, resulted into the high amounts of unordered structures as observed by FT-IR, as well as in an increase in the molecular scattering distances observed by SAXS. The water uptake increased and cooking loss decreased with increased proportions of the PF fraction, and the consistency of 10 min cooked pasta-like sheets were alike al dente texture. The new knowledge obtained in this study on the use of extraction-fractionation method to produce novel PPI and PF fractions for developing innovative high nutritious food can be of a great importance. The obtained knowledge on the pea protein and fiber processing behaviour could greatly contribute to a better control of functional properties of various temperature-processed products from yellow pea.
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| 10. |
- Newson, William, et al.
(author)
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Commercial potato protein concentrate as a novel source for thermoformed bio-based plastic films with unusual polymerisation and tensile properties
- 2015
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:41, s. 32217-32226
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Journal article (peer-reviewed)abstract
- Commercial potato protein concentrate (PPC) was investigated as a source of thermoformed bio-based plastic film. Pressing temperatures of 100 to 190°C with 15 to 25% glycerol were used to form PPC films. The shape of the tensile stress-strain curve in thermoformed PPC was controlled by glycerol level and was independent of processing temperature. Tensile testing revealed that elongation at break increased with processing temperature while Young's modulus was unaffected by processing temperature, both in contrast to previous results in protein based systems. Also in contrast to previous studies, Young's modulus was found to be only sensitive to glycerol level. Maximum tensile stress increased with increasing processing temperature for PPC films. Maximum stress and strain at break correlated with the extractable high molecular weight protein content of the processed films measured with size exclusion chromatography. Infrared absorption indicated that the content of β-sheet structure increased from the commercial protein concentrate to that pressed at 100°C, but did not further develop with increasing press temperature. Changes in structural arrangements were observed by small angle X-ray scattering indicating the development of different correlation distances with processing temperature but with no clear long range order at the supramolecular level. The novel Young's modulus behaviour appears to be due to constant secondary structure or the effect of aggregated protein structure formed during protein production. Unique strain at break behaviour with processing temperature was demonstrated, likely due to new connections formed between those aggregates.
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