Biopolymer Systems Research Articles

Charge Mediated Changes to the Intrinsic Viscosity of Biopolymer Systems

A theoretical approach is presented to quantify the effect of ionic strength on the swelling and shrinkage of the hydrodynamic coil size of a generic biopolymer. This was conducted in view of extraction methods that often utilize acids and alkali combinations and, therefore, invariably impact the levels of salt found in commercially available biopolymers. This approach is supplemented by intrinsic viscosity measurements for the purpose of validation across a variety of biopolymer architectures, type of functionalization, as well as the quoted molar mass. By accurately capturing the magnitude of change in the coil size, it is discussed how a biopolymer coil size is far more sensitive to changes in the ionic strength than it is to the molar mass (or contour length) itself. In turn, it is highlighted why the current characterization strategies that make use of weight-averaged molar mass are prone to errors and cannot be used to establish structure—property relationships for biopolymers. As an alternative, the scope of developing an accurate understanding of coil sizes due to changes in the “soft” interactions is proposed, and it is recommended to use the coil size itself to highlight the underlying structure—property relationships.

Using the Herschel-Bulkley Consistency Index to Characterise Complex Biopolymer Systems-The Effect of Screening.

The use of the consistency index, as determined from fitting rheological data to the Herschel-Bulkley model, is described such that it may yield systematic trends that allow a very convenient description of the dissipative flow properties of linear and branched (bio)polymers in general, both in molecular and weakly associated supramolecular solutions. The effects of charge-mediated interactions by the systematic variation of the ionic strength and hydrogen bonding by a systematic variation in pH, using levels that are frequently encountered in systems used in practice, is investigated. These effects are then captured using the associated changes in the intrinsic viscosity to highlight the above-mentioned trends, while it also acts as an internal standard to describe the data in a concise form. The trends are successfully captured up to 100 times the polymer coil overlap and 100,000 times the solvent viscosity (or consistency index). These results therefore enable the rapid characterization of biopolymer systems of which the morphology remains unknown and may continue to remain unknown due to the wide-ranging monomer diversity and a lack of regularity in the structure, while the macromolecular coil size may be determined readily.

Multitechnique approaches for characterising phase behaviour in food biopolymer systems

SummaryUnderstanding the phase behaviour of biopolymer composites is vital for various technological applications, such as developing functional foods, nutraceuticals, encapsulation, isolation and fractionation of enzymes and proteins. The growing consumer demand for healthier food products pressures the food and nutraceutical industries to innovate while maintaining traditional texture and nutritional quality. This review critically examines various analytical techniques, including spectroscopic, microscopic, calorimetric, rheological, viscometry, and diffraction methods, used to study phase behaviour. Each technique provides unique insights into phase behaviour mechanisms at micro and macroscopic levels, with respective advantages and limitations discussed. The review advocates for a multi‐technique approach for a comprehensive understanding of phase behaviour and highlights the development of in situ probing techniques with minimal sample pre‐processing as a promising advancement. These innovations are expected to significantly enhance the practical applications of these techniques in the food industry, meeting current consumer demands without compromising traditional qualities.

Recent Progress on the Application of Chitosan, Starch and Chitosan–Starch Composites for Meat Preservation—A Mini Review

The preservation of meat via sustainable methods and packaging is an area of continued interest driven by the need to address food security. The use of biomaterial films and coatings has gained significant attention due to their non-toxicity and biodegradability compared with conventional synthetic films. Starch and chitosan are sustainable sources for the preparation of films/coatings owing to their relatively low cost, natural abundance derived from numerous sources, biocompatibility, biodegradability, and antimicrobial, antioxidant, and film-forming attributes. These remarkable features have notably increased the shelf life of meat by inhibiting lipid oxidation and microbial activity in food products. Furthermore, recent studies have successfully incorporated binary biopolymer (starch and chitosan) systems to combine their beneficial properties upon composite formation. This literature review from 2020 to the present reveals that chitosan- and starch-based films and coatings have potential to contribute to enhanced food security and safety measures whilst reducing environmental issues and improving sustainability, compared with conventional synthetic materials.

Parameterization of General Organic Polymers within the Open Force Field Framework.

Polymer and chemically modified biopolymer systems present unique challenges to traditional molecular simulation preparation workflows. First, typical polymer and biomolecular input formats, such as Protein Data Bank (PDB) files, lack adequate chemical information needed for the parameterization of new chemistries. Second, polymers are typically too large for accurate partial charge generation methods. In this work, we employ direct chemical perception through the Open Force Field toolkit to create a flexible polymer simulation workflow for organic polymers, encompassing everything from biopolymers to soft materials. We propose and test a new input specification for monomer information that can, along with a 3D conformational geometry, parametrize and simulate most soft-material systems within the same workflow used for smaller ligands. The monomer format encompasses a subset of the SMIRKS substructure query language to uniquely identify chemical information and repeating charges in underspecified systems through matching atomic connectivity. This workflow is combined with several different approaches for automatic partial-charge generation for larger systems. As an initial proof of concept, a variety of diverse polymeric systems were parametrized with the Open Force Field toolkit, including functionalized proteins, DNA, homopolymers, cross-linked systems, and sugars. Additionally, shape properties and radial distribution functions were computed from molecular dynamics simulations of poly(ethylene glycol), polyacrylamide, and poly(N-isopropylacrylamide) homopolymers in aqueous solution and compared to previous simulation results in order to demonstrate a start-to-finish workflow for simulation and property prediction. We expect that these tools will greatly expedite the day-to-day computational research of soft-matter simulations and create a robust atomic-scale polymer specification in conjunction with existing polymer structural notations.

Electron Beam-Modified Collagen Type I Fibers: Synthesis and Characterization of Mechanical Response.

Ten MeV electron beam treatment facilitates a biomimetic introduction of cross-links in collagenous biopolymer systems, modifying their viscoelastic properties, mechanical stability, and swelling behavior. For reconstituted collagen type I fibers, electron-induced cross-linking opens up new perspectives regarding future biomedical applications in terms of tissue and ligament engineering. We demonstrate how electron irradiation affects stiffness both in low-strain regimes and in postyield regimes of biocompatible reconstituted rat tail collagen type I fibers. Stress-strain tests show a dose-dependent increase in modulus in the nonlinear elastic response, indicating a central role of induced cross-links in mechanical stability. Environmental scanning electron microscopy after fiber rupture reveals aligned distributed collagen fibril domains under the fiber surface for as-prepared fibers, accompanied by a ductile fracture behavior, whereas, in tensile tests imaged by light microscopy after 10 MeV electron treatment, isotropic network topologies are observed until the occurrence of a brittle type of rupture. Based on the biomimicry of the process, these findings might pave the way for a novel type of synthesis of tailored tendon or ligament substitutes.

Preparation and Application of Complexes Based on Biopolymers of Animal Origin

Immobilization of enzymes (IoE) from animal origin on natural carriers increases the system stability; facilitates the separation and accelerates the recovery of the enzyme; makes reuse possible; provides a significant reduction in operating costs. There are numerous IoE methods and systems, including immobilization of various lipases on major carbohydrate biopolymers (chitin, chitosan, cellulose, etc.), discussed in this review. The key points of the most encouraging methods “for increasing the activity and stability” of such biopolymer systems are the “chitosan particle activation” by “ultra-sonication” and multiplicative “addition of glutaraldehyde” to these abovementioned systems. The design of such complex biopolymer preparations (in their various forms) is an important area of modern agrosciences, biomedicine, veterinary, zootechnology and bionanotechnology.

Preparation of Boron Carbide Biopolymer Systems with One Step Sol–Gel Synthesis for pH-Controlled Drug Delivery

Preparation of Boron Carbide Biopolymer Systems with One Step Sol–Gel Synthesis for pH-Controlled Drug Delivery

Fundamentals and Applications of Raman-Based Techniques for the Design and Development of Active Biomedical Materials.

Raman spectroscopy is an analytical method based on light-matter interactions that can interrogate the vibrational modes of matter and provide representative molecular fingerprints. Mediated by its label-free, non-invasive nature, and high molecular specificity, Raman-based techniques have become ubiquitous tools for in situ characterization of materials. This review comprehensively describes the theoretical and practical background of Raman spectroscopy and its advanced variants. The numerous facets of material characterization that Raman scattering can reveal, including biomolecular identification, solid-to-solid phase transitions, and spatial mapping of biomolecular species in bioactive materials, are highlighted. The review illustrates the potential of these techniques in the context of active biomedical material design and development by highlighting representative studies from the literature. These studies cover the use of Raman spectroscopy for the characterization of both natural and synthetic biomaterials, including engineered tissue constructs, biopolymer systems, ceramics, and nanoparticle formulations, among others. To increase the accessibility and adoption of these techniques, the present review also provides the reader with practical recommendations on the integration of Raman techniques into the experimental laboratory toolbox. Finally, perspectives on how recent developments in plasmon- and coherently-enhanced Raman spectroscopy can propel Raman from underutilized to critical for biomaterial development areprovided.

STUDY OF THE VARIABILITY OF RHEOLOGICAL PROPERTIES OF WATER-BASED BIOPOLYMER DISPERSIONS IN DRILLING FLUIDS

Link for citation: Lambin A.I., Averkina E.V. Study of the variability of rheological properties of water-based biopolymer dispersions in drilling fluids. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 91-97. In Rus. The relevance. Water-based biopolymer drilling fluids have become quite widespread in the technology of oil and gas well construction. Much attention is paid to the methods of regulating the physical and mechanical properties of biopolymer systems. In particular, rheological properties of solutions based on xanthan gum are of great practical interest. The effectiveness of the use of polymers is determined by the amount of the main reagent and modifying additives necessary to impart the required properties to the washing liquid. Biopolymer water drilling fluids based on xanthan gum have shown their effectiveness in many regions of the Russian Federation. However, the evaluation of the effectiveness of the solutions is difficult due to the differences in the saleable products of the producing companies in solubility, swelling and composition, which affects the optimized performance of the drilling mud. The main aim: consideration of the differences in aqueous solutions of a number of samples of xanthan gum in terms of power dependence: K-coefficient of consistency and n-degree of deviation from the Newtonian flow regime of the study. Objects: rheology of aqueous solutions of several xanthan samples, both purely aqueous and based on aqueous brines of potassium chloride (KCl) and sodium (NaCl). Methods: instrumental methods for determining the parameters of drilling fluids according to SS 33213-2014; the difference in the parameters of the power rheological dependence was determined by comparing its indicators after measuring the viscosity of solutions on a viscometer with direct indications. Results. The influence of a fixed concentration of NaCl and KCl salts on the considered indicators of the power model is shown. A generalized optimization indicator is proposed for solutions obeying a power-law rheological law. The calculated dependence of the accuracy of approximation of experimental data by a power model, which showed acceptable accuracy, is presented.

To the assessment of thermal stability of biopolymer systems

To diagnose thermal stability based on rotational viscometry data, an integral index for assessing the rheological properties of drilling fluids has been proposed. It is independent of their rheological model under thermobaric conditions of the well. According to the laboratory research of xanthan gum-based biopolymer systems, the possibility of assessing thermal stability in regard to the dependence of the integral index on temperature has been shown. The accuracy of thermal stability assessment has been confirmed by laboratory studies of the Biocar-TF biopolymer system at temperatures up to 170 ℃.

Characterization of chitosan-gelatin cryogel templates developed by chemical crosslinking and oxidation resistance of camellia oil cryogel-templated oleogels

In this study, chitosan-gelatin conjugates were prepared by chemical crosslinking of tannic acid. The cryogel templates were developed through freeze-drying and immersed in camellia oil to construct cryogel-templated oleogels. Chemical crosslinking resulted in apparent colour changes and improved emulsion-related/rheological properties on conjugates. The cryogel templates with different formulas exhibited different microstructures with high porosities (over 96 %), and crosslinked samples might have higher hydrogen bonding strength. Tannic acid crosslinking also led to enhanced thermal stabilities and mechanical properties. Cryogel templates could reach a considerable oil absorption capacity of up to 29.26 g/g and prevent oil from leaking effectively. The obtained oleogels with high tannic acid content possessed outstanding antioxidant abilities. After 8 days of rapid oxidation at 40 °C, Oleogels with a high degree of crosslinking owned the lowest POV and TBARS values (39.74 nmol/kg, and 24.40 μg/g, respectively). This study indicates that the involvement of chemical crosslinking would favor the preparation and the application potential of cryogel-templated oleogels, and the tannic acid in the composite biopolymer systems could act as both the crosslinking agent and the antioxidant.

Low Cost Biopolymer Adsorbents for the Removal of Heavy Metal Contaminant from Wastewater

AbstractPolymeric materials have been remarkably associated with our daily life. The hydrophilic/hydrophobic biopolymer systems have gained importance in the last few years, because of the environmental pollution of nonbiodegradable synthetic plastics. Recently, biopolymers with functional groups have been directly used for the fabrication of adsorptive membranes in order to avoid the undesirable morphology change of the membranes during the surface modifications. Compared with other modification technologies or a synthesis of totally new materials, biopolymer blending has several advantages like simplicity, reproducibility, and commercial feasibility. The valuable part of blending of biopolymers can be used for the preparation of new materials with improved physicochemical and mechanical properties. The objective of this work is the development of biomembranes based on a mixture of three biopolymers, that is, alginate (AL), chitosan (CS), and polylactic acid (PLA). Physical characterizations of the elaborated biopolymeric membranes are carried out by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and contact angle measurements. The SEM results show that the synthesized membranes exhibited homogeneous dense microstructures. The second objective of this paper is to evaluate the importance of these biopolymers in removing lead which is considered as toxic metal. In fact, all synthesized membranes are applied to the treatment of wastewater to eliminate heavy metals principally Pb2+.

The Glass Transition Temperature of Heterogeneous Biopolymer Systems.

Biopolymers are abundant, renewable, and biodegradable resources. However, bio-based materials often require toughening additives, like (co)polymers or small plasticizing molecules. Plasticization is monitored via the glass transition temperature versus diluent content. To describe this, several thermodynamic models exist; nevertheless, most expressions are phenomenological and lead to over-parametrization. They also fail to describe the influence of sample history and the degree of miscibility via structure-property relationships. We propose a new model to deal with semi-compatible systems: the generalized mean model, which can classify diluent segregation or partitioning. When the constant kGM is below unity, the addition of plasticizers has hardly any effect, and in some cases, even anti-plasticization is observed. On the other hand, when the kGM is above unity, the system is highly plasticized even for a small addition of the plasticizer compound, which indicates that the plasticizer locally has a higher concentration. To showcase the model, we studied Na-alginate films with increasing sizes of sugar alcohols. Our kGM analysis showed that blends have properties that depend on specific polymer interactions and morphological size effects. Finally, we also modeled other plasticized (bio)polymer systems from the literature, concluding that they all tend to have a heterogeneous nature.

Near-Surface Nanomechanics of Medical-Grade PEEK Measured by Atomic Force Microscopy.

Detecting subtle changes of surface stiffness at spatial scales and forces relevant to biological processes is crucial for the characterization of biopolymer systems in view of chemical and/or physical surface modification aimed at improving bioactivity and/or mechanical strength. Here, a standard atomic force microscopy setup is operated in nanoindentation mode to quantitatively mapping the near-surface elasticity of semicrystalline polyether ether ketone (PEEK) at room temperature. Remarkably, two localized distributions of moduli at about 0.6 and 0.9 GPa are observed below the plastic threshold of the polymer, at indentation loads in the range of 120-450 nN. This finding is ascribed to the localization of the amorphous and crystalline phases on the free surface of the polymer, detected at an unprecedented level of detail. Our study provides insights to quantitatively characterize complex biopolymer systems on the nanoscale and to guide the optimal design of micro- and nanostructures for advanced biomedical applications.

Advantages of treating sponge-gourd waste by mechanical refining on the properties of fiber-based poly(butylene adipate-co-terephthalate)/polylactide biocomposites.

This study compares the morphology, thermal, and dynamic-mechanical properties of composites based on polybutylene adipate terephthalate/polylactide biocomposites with sponge gourd waste treated code as R, and non-treated sponge gourd, coded as NR, by mechanical disc refining after milled process. Extrusion followed by compression molding was used to produce biocomposites with fiber contents of 0, 2.5, 5, 10, and 15% wt/wt for R and NR sponge gourd fibers. Scanning electron microscopy analysis reveals that NR has the morphology of a rigid tubular shape, whereas R is a thinner, twisted, and fibrillated fiber. Regardless of the type of sponge gourd fiber used, the thermal stability of the composite decreases as the sponge gourd content increases. At 25°C, the biocomposite with 10%wt/wt R fiber has the highest storage modulus value. The comparison of Tangent  peak values reveals that the presence of sponge gourd fibers reduces the energy dissipation of the biocomposites. The analysis of the loss modulus at 25°C reveals that R fiber contributes more to the reduction of energy dissipation of the biocomposites than NR. Furthermore, the Cole-Cole plot shows that R and NR fibers are dispersed and do not significantly change the homogeneity of the biopolymer systems.

Foaming properties are improved by interactions between brewer's spent grain proteins and carrageenans in aqueous solution.

Foaming properties and macromolecular interactions in solution among brewer's spent grain proteins (CP) and iota and lambda carrageenans (i-CG and l-CG, respectively) as a function of aqueous medium pH (2-6) and protein-polysaccharide ratio, RCP:CG (1:1, 2:1 and 4:1), were studied. At these conditions, the CP colloidal stability was favored by the formation of soluble electrostatic complexes with CG. Fluorescence (intrinsic and extrinsic) spectroscopy and dynamic light scattering techniques, including particle size and ζ-potential analysis, were applied to know the phase behavior of the biopolymer systems. The bubbling method was used to produce foams, and the foam expansion (%) and half-life time (t1/2 ) were determined. Both CG promoted an increased Trp fluorescence emission depending on the pH, suggesting conformational changes in CP. The CG in mixed systems produced a significant decrease in the extrinsic fluorescence intensity, mainly at low pH values, highlighting a reduction in CP surface hydrophobicity. At the examined pH range, the ζ-potential values for mixed-systems were negative, and their magnitudes were intermediate between CP and CG, revealing the associative electrostatic nature of biopolymer interactions, which were dependent on the RCP:CG . The particle size analysis confirmed the formation of soluble electrostatic complexes in solution. Finally, using i-CG at pH 2 or 3 and 2:1 RCP:CG , the best foaming properties for mixed systems were observed. The formation of electrostatic complexes with a compact assembly among biopolymers, high negative net charge, and colloidal stability convert the CP-CG mixed solutions into promising biopolymer systems for food foams production. © 2022 Society of Chemical Industry.

Physically Cross-Linked Biopolymer Systems Based on Chitosan and Hydroxycinnamic Acids and Their Food Preservation Application Studies

Production of physically cross-linked biopolymer systems (PCBS) is attracting scientific and industrial attention due to its proven potential for applications in, for example, food, food packaging, food preservation, pharmaceuticals, and cosmetic industries. Its production versatility allows obtaining products in the form of films, powders, lyophilized products, edible coatings, and gel beads, among others. This review presents different methods for obtaining, characterizing, and applying these PCBS designed and produced using chitosan (CH) and hydroxycinnamic acids (HAs), resulting exclusively from noncovalent interactions. Each variable characterizing each component of the PCBS is evaluated, gaining a better understanding of their roles. The influence of different molecular weights, viscosities, and degree of deacetylation among other variables belonging to the biopolymer is presented, while the role of the type, amount, and position of the substituent groups on the HAs is shown using caffeic, ferulic, coumaric, chlorogenic, and rosmarinic acids as physical cross-linkers. The molar ratio between HAs and CH is a key factor when forming PCBS and in determining their final properties. Thus, we provide a comprehensive study of these PCBS obtained using CH and HAs, highlighting their environmental and sustainable aspects. Benefits from a materials standpoint regarding their competitive barrier effects and mechanical and thermal properties are also emphasized, especially toward their food packaging and food preservation applications.

Mixed Biopolymer Systems Based on Bovine and Caprine Caseins, Yeast β-Glucan, and Maltodextrin for Microencapsulating Lutein Dispersed in Emulsified Lipid Carriers.

Lutein is an important antioxidant that quenches free radicals. The stability of lutein and hence compatibility for food fortification is a big challenge to the food industry. Encapsulation can be designed to protect lutein from the adverse environment (air, heat, light, pH). In this study, we determined the impact of mixed biopolymer systems based on bovine and caprine caseins, yeast β-glucan, and maltodextrin as wall systems for microencapsulating lutein dispersed in emulsified lipid carriers by spray drying. The performance of these wall systems at oil/water interfaces is a key factor affecting the encapsulation of lutein. The highest encapsulation efficiency (97.7%) was achieved from the lutein microcapsules prepared with the mixed biopolymer system of caprine αs1-II casein, yeast β-glucan, and maltodextrin. Casein type and storage time affected the stability of lutein. The stability of lutein was the highest (64.57%) in lutein microcapsules prepared with the mixed biopolymer system of caprine αs1-II casein, yeast β-glucan, and maltodextrin, whereas lutein microcapsules prepared with the biopolymer system of bovine casein, yeast β-glucan, and maltodextrin had the lowest (56.01%). The stability of lutein in the lutein microcapsules dramatically decreased during storage time. The antioxidant activity of lutein in the lutein microcapsules was closely associated with the lutein concentration.

CO2 induced gelation of amidated pectin solutions: Impact of viscosity and gel formation

CO2 induced gelation of aqueous biopolymer systems results in stable and homogeneous hydrogels with a wide field of potential applications in food and pharmaceutical industry. For the application of the process in industry, good understanding of process parameters and their impact on the overall process and the gel properties is necessary. The mechanism of the CO2 induced gelation is not fully understood; the role of viscosity has never been addressed in the literature. The first step of the overall gelation process, the dissolution of CO2 into the biopolymer systems, is limiting for the overall process. Therefore, it was investigated in this work with different non-invasive, in-situ measurement methods: magnetic suspension balance and Raman spectroscopy on the system of amidated pectin with calcium carbonate (CaCO3) as additional cross-linker. With increasing viscosity of the biopolymer system, due to increasing amidated pectin mass fraction, the CO2 dissolution is slowed down. For non-gelling, CaCO3-free biopolymer systems effective diffusion coefficients from 17.7·10-9 to 5.6·10-9 m2/s were determined for solutions with increasing complex viscosities from 0.011 to 0.379 Pa s (0.5 to 2 wt.-% amidated pectin). In this case, the effective diffusion coefficient considers mass transport due to pure diffusion and due to free convection. Inside the non-gelling biopolymer systems, free convection appears and no gradient of the CO2 concentration inside the samples occurs. Nevertheless, in gelling, CaCO3 containing, biopolymer systems the formation of the gel network (gelation) itself has a strong impact on CO2 dissolution, as it hinders free convection. Due to gelation, the effective diffusion coefficient is decreased down to about 2.5·10-9 m2/s and approaches the binary diffusion coefficient of CO2 in water; indicating pure diffusion of CO2 in pores that contain mainly pure water. At 50 bar and room temperature CO2 solubility of 0.043 ± 0.003 g of CO2 per gram of the aqueous system, nearly independent of solution composition and gelation was measured. Contrarily, increasing temperatures as well as decreasing pressure results in decrease of overall CO2 solubility, whereas increasing temperature does enhance dissolution and distribution kinetics. With the performed measurements, it was possible to distinguish between the impacts of viscosity, gelation, and the formed gel network on the CO2 dissolution kinetics inside the sample, respectively.