Protein Films Research Articles

Investigation of the film-forming ability of proteins subjected to UV treatment for the dairy industry development

Film-forming mixtures based on reconstituted solutions of whey protein concentrates (WPC) with a protein content of 2.0 and 5.0% were subjected to UV irradiation in the range from 90 to 150 J/ml. With an increase in the dose of UV irradiation in film-forming solutions, the solubility of the protein decreased, the greatest effect was achieved in a mixture with a protein content of 2.0%. The decrease in solubility indirectly proved the process of aggregation of protein molecules in the studied solutions. It has been shown that UV exposure improves the strength properties of protein films. The highest specific stress at film rupture at an irradiation dose of 150 J/ml was 23.11 MPa in a 5.0% protein solution and 5.74 MPa in a 2.0% solution. The indicator of the applied force increased more intensively when processing a 5.0% protein solution, and amounted to 16.00 N in the case of a 2.0% solution, and 24.82 N in a 5.0% solution.

Improving the clinical effectiveness of the treatment of acute inflammatory diseases of the upper respiratory tract in children with the use of silver-based medicines

Introduction. Acute respiratory viral infection (ARVI) is the most common reason for visits to the physician by both children and adults.The aim of the study was to analyse the features of the course of ARVIs in patients with different immune status, to evaluate the effectiveness of standard therapy for these groups of patients, as well as the use of silver-based medicines in the combination therapy of patients.Materials and methods. For the period from July to September 2022, 26 children (Group 1) without immunodeficiency conditions and 26 immunocompromised children (Group 2) were identified, all of them had symptoms of acute respiratory viral infections. In Group 1, 69.2% of children (n = 18) were classified as frequently ill children with ARVI rate of more than 8 times per year, 38.4% (n = 10) had allergic rhinitis, 7.7% (n = 2) had a concomitant bronchial asthma. In Group 2, the distribution of underlying immunocompromised disease was as follows: primary immunodeficiency – 7.7% (n = 2), Hurler syndrome after bone marrow transplantation – 11.5% (n = 3), acute lymphoblastic leukemia during specific therapy – 26.9% (n = 7), with graft versus host disease – 30.7% (n = 8) and currently in remission – 23% (n = 6). Among patients in this Group, only 7.7% of children (n = 2) had a history of allergic rhinitis.Results. The criterion for recovery in Group 1 was reversal of all clinical symptoms, in Group 2 – clinical improvement, normalization or significant decrease in C-reactive protein levels, improvement of paranasal sinuses pneumatization.Conclusion. During ARVI, post-viral rhinosinusitis often occurs, the ability of the mucosa to regenerate becomes disturbed, which makes it more vulnerable to adhesion of viruses, bacteria, and fungi. In this case, especially effective is the intranasal use of a silver-based medicine to form a protective protein film on the injured mucosa. The use of silver-based medicines in the combination therapy of patients with inflammatory pathologies of the nose, nasopharynx and paranasal sinuses can greatly increase the effectiveness of treatment, while shortening the duration of therapy and being safe.

Untangling effects of proteins as stabilizers for foam films

Foam film’s properties have a high impact on the properties of the macroscopic foams. This work focusses on protein stabilized foam films. The direct comparison of three different proteins with a concentration normalized to the protein surface enables to distinguish between electrostatic, steric and network stabilization effects. In order to untangle those effects, we study and compare two globular proteins (β − lactoglobulin, BLG, and bovine serum albumin, BSA) and a disordered, flexible protein (whole casein, CN) at low ionic strengths with varying solution pH. Image intensity measurement as a recently developed image analysis method in this field allows to record spatially resolved disjoining pressure isotherms in a Thin Film Pressure Balance (TFPB). This reveals insights into the structure formation in inhomogeneous protein films. As a novel method we introduce tracking inhomogeneities (features) which enables the measurement of interfacial mobility and stiffness of foam films. Around the isoelectric point (IEP), Newton Black Films (NBF) form which are stable for the globular proteins while they are unstable for the disordered flexible one. This difference in film stability is explained by different characteristics of the network structures which is supported by findings in the bulk and at the surface of the respective protein solutions.

Effect of Corn Starch Granules on Stabilizing the Foam Structure of Ultrasonically Modified Whey Isolate Protein.

In this study, the mechanism of ultrasound combined with corn starch granules (CSG) treatment improved the foam properties of whey protein isolates (WPI) and was systematically investigated. The results showed that ultrasound combined with corn starch granules treatment increased foam capacity and stability by 15.38% and 41.40%, respectively. Compared with the control group, corn starch granules enhanced the surface charge (52.38%) and system turbidity (51.43%), which certainly provided the necessary conditions for the improvement of foam stabilization stability. In addition, corn starch granules as microgel particles increased the mechanical properties of the interfacial protein film, thus delaying the instability of foam. This research would provide new insights into the design of new protein-based foam foods in the future food industry.

Distinction between film loss and enzyme inactivation in protein-film voltammetry: a theoretical study in cyclic staircase voltammetry

Inactivation of redox enzymes and the loss of enzyme’s material from its adsorbed film on electrode surface are events that have similar outputs when studied under conditions of protein-film voltammetry. In the current work, we present a series of novel theoretical results under conditions of protein-film cyclic staircase voltammetry that clearly reveal how to distinguish between these two events. Theoretical model elaborated in this work comprises a surface electrode mechanism in which the initial form of redox enzyme is involved in same time in an electrode transformation and in an irreversible reaction of deactivation. While a large set of theoretical voltammetric curves simulated at different conditions are discussed, we also give a tabular overview of some characteristic cyclic voltammetric patterns of this electrode mechanism. The simulated voltammograms can help the experimentalists to distinguish the phenomenon of loss of protein film from the electrode mechanism associated with enzyme deactivation. In addition, we give hints to apply suitable methodologies to get access to the kinetics of both steps involved in this electrochemical mechanism.Graphical abstract

Highly ductile corn protein films cross-linked with biobased aldehydes for biomedical and packaging applications

Highly ductile corn protein films cross-linked with biobased aldehydes for biomedical and packaging applications

Pneumocoelomogram as a novel negative contrast diagnostic imaging technique to evaluate coelomic organs in bearded dragons (Pogona vitticeps)

Contrast radiography is used to combat poor coelomic detail encountered in reptilian radiographs. This study describes pneumocoelomography, a novel negative contrast technique using room air in bearded dragons ( Pogona vitticeps ). The feasibility of this technique, its tolerance by the study subjects, and obtained images were evaluated. Six clinically healthy, adult bearded dragons had standard and pneumocoelomogram radiographs performed under anesthesia. Pneumocoelom was induced by insufflating 0.2mL/mm coelomic length of room air via an over-the-needle catheter introduced into the coelom. Pre-, post-, and positive intravenous contrast-enhanced post-pneumocoelom computed tomography scans were also performed. Packed cell volume, total protein, and blood films were evaluated at time of imaging and two weeks post-procedure to assess potential systemic consequences of this technique. Procedures were well tolerated with no adverse anesthetic, recovery, post-procedural, hematologic, or behavioral declines in health status. The pneumocoelomogram consistently revealed the gonads (6/6 cases) in both sexes. There was an inconsistently improved characterization of other coelomic organs: the cardiac silhouette was improved in 4/6 cases, trachea in 2/6, lungs in 3/6, stomach in 3/6, cecum in 3/6, colon in 5/6, and kidneys in 2/6. The liver, spleen, and small intestines did not show improved characterization in any case. Room air pneumocoelomography offers a well-tolerated, readily-available technique and provides additional coelomic organ characterization to that of standard radiographs. Future studies should evaluate if this technique provides diagnostic utility in pathological states.

Physical and textural properties of functional edible protein films from soybean using an innovative 3D printing technology.

Increasing market demand for sustainable, environmentally friendly edible film materials has called for the development of new customizable production methods utilizing emerging technologies such as 3D printing. We hereby report a new method to generate functional edible soy protein isolate films prepared from three types of soybeans (AR-R11-7999, MO-S17-17168, and MO-S17-19874R) using an innovative 3D printing technology. The protein contents in AR-R11-7999, MO-S17-17168, and MO-S17-19874R soybean meals and their corresponding protein isolates were 40.0, 39.1, and 39.9; and 84.5, 84.7, and 87.3 % (w/w, dry basis), respectively. Response surface methodology was used to maximize the tensile and puncture strength and minimize the thickness of the 3D-printed edible films using protein concentration, plasticizer concentration (glycerol), and drying time as the independent variables. The optimized film production conditions were determined as soy protein concentration: 8.91%, plasticizer concentration: 3.00%, and drying time: 3.98h with a desirability value of 0.7428. The optimized conditions were then successfully verified with the original soybean lot with a nonsignificant difference in physical properties. At the optimized conditions, the 3D-printed edible films using three soybean lots revealed: 0.108-0.114mm thickness; 14.79-16.07MPa tensile strength; 6.97-8.20 N puncture strength; 90.81-91.53, -1.89 to -1.31, and 14.85-17.25 were color parameters L*, a*, and b*, respectively; 1.22-1.36g/cm3 density; and 104.4-105.7% elongation at break ratio (%). PRACTICAL APPLICATION: Edible soy protein films produced by an extrusion-based 3D printing approach are highly customizable and precise, and could be produced at an industrial scale. This newly produced environment-friendly soy protein-based edible film can serve as an alternate packaging to synthetic plastics and reduce the environmental landfill problem while adding value to soybean produced in the mid-south United States.

Physicochemical properties and digestibility of thermally induced ovalbumin–oil emulsion gels: Effect of interfacial film type and oil droplets size

To investigate the effect of oil droplets surface film type and droplets size on the physicochemical properties and digestibility of thermally induced ovalbumin–oil emulsion gels, Tween 80 and ovalbumin were selected as individual emulsifiers for the emulsification of sunflower oil at different homogenization speeds (6000, 8000, and 10000 rpm), and the formed emulsions were mixed with ovalbumin matrix solution and then heated to form heat-induced ovalbumin emulsion gels (OEG). The OEG with ovalbumin as emulsifier had higher hardness, water holding capacity (WHC), and surface hydrophobicity, and lower digestibility, spin−spin relaxation time ( T 2 ) and free sulfhydryl content than those of the OEG with Tween 80 as the emulsifier ( p < 0.05). As the oil droplets size decreased, the hardness increased, WHC increased, the amide A band shifted to lower wavenumbers, digestibility decreased, T 2 decreased, free sulfhydryl content decreased, and surface hydrophobicity increased for both OEG ( p < 0.05). These results collectively indicated that the physicochemical properties of the OEG are influenced by the property of the oil interfacial film and the size of the oil droplets. The oil droplets surrounded by the interfacial protein film improved the performance of the OEG greatly, and the proteins within its OEG formed a dense gel network structure through hydrophobic aggregation, disulfide bond crosslinking, and hydrogen bonding. The oil droplets with smaller sizes favored the enhancement in the physicochemical properties of the OEG. Changes in the size of oil droplets and the type of film wrapped around them regulated the digestibility of the OEG. • The OEG-O with the small size of oil droplets had the highest hardness. • Small oil droplets filled better in the gel network to improve the hardness of OEG. • IPF-encapsulated oil droplets as active filler to increase the hardness of OEG. • Effect of filler on hardness depends on the heat stability of its interfacial layer. • Changes in oil droplet size and interfacial layer type regulated OEG digestibility.

Reaching the breaking point: Effect of tubing characteristics on protein particle formation during peristaltic pumping

Peristaltic pumping has been identified as a cause for protein particle formation during manufacturing of biopharmaceuticals. To give advice on tubing selection, we evaluated the physicochemical parameters and the propensity for tubing and protein particle formation using a monoclonal antibody (mAb) for five different tubings. After pumping, particle levels originating from tubing and protein differed substantially between the tubing types. An overall low shedding of tubing particles by wear was linked to low surface roughness and high abrasion resistance. The formation of mAb particles upon pumping was dependent on the tubing hardness and surface chemistry. Defined stretching of tubing filled with mAb solution revealed that aggregation increased with higher strain beyond the breaking point of the protein film adsorbed to the tubing wall. This is in line with the decrease in protein particle concentration with increasing tubing hardness. Furthermore, material composition influenced particle formation propensity. Faster adsorption to materials with higher hydrophobicity is suspected to lead to a higher protein film renewal rate resulting in higher protein particle counts. Overall, silicone tubing with high hardness led to least protein particles during peristaltic pumping. Results from this study emphasize the need of proper tubing selection to minimize protein particle generation upon pumping.

Research on the Properties of Zein, Soy Protein Isolate, and Wheat Gluten Protein-Based Films Containing Cellulose Nanocrystals.

Plant protein films are a research hotpot in the current food packaging field for their renewable and bio-compatibility, and further improving the physicochemical properties of plant protein films in combination with biodegradable materials is of great significance. In this study, we selected cellulose nanocrystals (CNC) to modify the protein films with soybean protein isolate (SPI), wheat gluten protein (WGP), and Zein, and the physicochemical properties were studied. The results showed that the hardness and opacity of Zein-based films decreased by 16.61% and 54.12% with the incorporation of CNC, respectively. The SPI-based films performed with lower hardness and higher tensile strength. The thickness and opacity of WGP-based films increased by 39.76% and 214.38% after combination with CNC, respectively. Accordingly, this study showed that CNC could largely modify the physicochemical properties of the plant protein films, which provided a reference for the preparation of modified plant protein films using biodegradable materials.

Effects of Interfacial Interactions on Electrocatalytic Activity of Cytochrome c Oxidase in Biomimetic Lipid Membranes on Gold Electrodes.

Effects of interfacial interactions on the electrocatalytic activity of protein-tethered bilayer lipid membranes (ptBLMs) containing cytochrome c oxidase (CcO) for the oxygen reduction reaction are studied by using protein film electrochemistry and surface-enhanced infrared absorption (SEIRA) spectroscopy. Mammalian CcO was immobilized on a gold electrode via self-assembled monolayers (SAMs) of mixed alkanethiols. The protein orientation on the electrode is controlled by SAM-CcO interactions and is critical to the cytochrome c (cyt c) binding. The CcO-phospholipid and CcO-cyt c interactions modulate the electrocatalytic activity of CcO, and more densely packed ptBLMs show higher electrocatalytic activity. Our study indicates that spectroscopic and electrochemical studies of ptBLMs can provide insights into the effects of relatively weak protein-protein and protein-lipid interactions on the enzymatic activity of transmembrane enzymes.

Tough and strong soy protein film by integrating CNFs and MXene with photothermal conversion and UV-blocking performance

Tough and strong soy protein film by integrating CNFs and MXene with photothermal conversion and UV-blocking performance

Insights into ultrasonic treatment on the properties of pullulan/oat protein/nisin composite film:mechanical, structural and physicochemical properties

This study developed two novel food packaging films, oat protein/pullulan (Op/Pul) and Nisin-loaded oat protein/pullulan (Nis@Op/Pul) films. Ultrasound was introduced to improve its mechanical, structural and physicochemical properties. The Op/Pul film has lower light transmittance, water vapour and oxygen permeability (OP) and improved film uniformity than pure oat protein and pullulan film. The addition of Nisin led to a significant decrease in the composite films' transparency, moisture content, and total soluble matter (TSM). The ultrasound treatment significantly increased the elongation at break and transparency of Nis@Op/Pul film by 18.37% and 8.03% and decreased its TSM and OP by 8.33% and 2.78%, respectively, compared to the conventional method. The structure analysis shows ultrasound enhances intermolecular hydrogen bonding, reduces the crystallinity and formed a more regular, uniform surface. Moreover, the Nis@Op/Pul film prepared by ultrasound treatment could effectively delay the decay and deterioration of fresh strawberries and prolong their shelf life.

Green Synthesis of Iron Nanoparticles Loaded on Bovine Lactoferrin Nanoparticles Incorporated into Whey Protein Films in Food Applications

Green Synthesis of Iron Nanoparticles Loaded on Bovine Lactoferrin Nanoparticles Incorporated into Whey Protein Films in Food Applications

The effect of pine cone lignin on mechanical, thermal and barrier properties of faba bean protein films for packaging applications

In the present work, faba bean protein (FBP) films plasticized with glycerol and reinforced with different amounts (2.5, 5.0, 7.5 and 10% by weight of FBP) of lignin extracted from pine cones (PL) have been obtained by solution casting. The results obtained showed an elongation at break of 111.7% with the addition of 5% PL to the FBP film, which represents an increase of 107% compared to the FBP control film. On the other hand, it was observed by thermogravimetric analysis (TGA) that the incorporation of lignin improved the thermal stability of the FBP film, leading to an increase in the protein degradation temperature, being this increase higher in the sample film reinforced with 10% PL. The barrier properties of the FBP films were also affected by the presence of lignin, leading to a decrease in water vapor permeability (WVP) in comparison to the unreinforced film. The results show that the sample reinforced with 2.5% PL had the lowest WVP value, with a reduction of 25% compared to the control film. Chemical analysis by Fourier transform infrared spectroscopy (FTIR) confirmed the formation of intramolecular interactions between lignin and proteins which, together with the inherent hydrophobicity of lignin, resulted in a decrease of the moisture content in the films reinforced with PL. This research work has allowed the development of biobased and biodegradable films with attractive properties that could be of potential use in sectors such as packaging.

A novel hydrophobin encoded by hgfII from Grifola frondosa exhibiting excellent self-assembly ability.

Hydrophobins are small proteins from filamentous fungi, which have remarkable self-assembly properties of great potential, e.g., as drug carriers and as anti-bacterial agents, but different hydrophobins, with improved properties, are needed. HGFI (a hydrophobin from Grifola frondosa) is a class I hydrophobin, which can self-assemble into rodlet structures with a length range 100–150 nm. In this study, we identified a new hydrophobin gene (hgfII) from the mycelium of G. frondosa with a much higher transcriptional level than hgfI. Heterologous expression of hgfII was accomplished in the Pichia pastoris. X-ray photoelectron spectroscopy and water contact angle assay measurements revealed that HGFII can self-assemble into a protein film at the air–solid interface, with circular dichroism and thioflavin T fluorescence studies showing that this effect was accompanied by a decrease in α-helix content and an increase in β-sheet content. Using atomic force microscopy, it was shown that HGFII self-assembled into rodlet-like structures with a diameter of 15–30 nm, showing that it was a class I hydrophobin, with self-assembly behavior different from HGFI. The surface hydrophobicity of HGFII was stronger than that of HGFI, meanwhile, in emulsification trials, HGFII displayed better dispersive capacity to the soybean oil than HGFI, producing a more stable and durable emulsion.

Unraveling molecular interactions in whey protein-kefiran composite films to understand their physicochemical and mechanical properties

To enhance health promoting properties of edible whey protein films, the inclusion of kefiran to develop composite films was studied. Physicochemical and mechanical properties of films prepared with different wpi:kefiran ratios, different percentage of plasticizer and subjected or not to a heat treatment were analyzed. The inter- and intra-molecular interactions produced by the incorporation of kefiran into whey-protein films were studied to understand the effect exerted by kefiran on the protein network that may affect the properties of the films. Differential-scanning-calorimetry and Fourier-transform–infrared-spectroscopy studies revealed that kefiran does not affect proteins denaturation, but rather modifies protein-protein interactions in the films, exhibiting a change in wpi secondary structure and a drop in films' melting temperature. Composite wpi:kefiran films had higher opacity, lower water content and lower water activity compared to single wpi films. Incorporation of kefiran into the films decreases tensile strength and elastic modulus and produces an increment in the elongation at break value. It was confirmed that the addition of a whey-protein denaturation step produces an improvement in the protein network that is crucial for the mechanical behavior of the films. Understanding the molecular interactions within composite films greatly aids in obtaining novel formulations with tailor-made physicochemical properties.

Modification of Tubings for Peristaltic Pumping of Biopharmaceutics

Protein particle formation during peristaltic pumping of biopharmaceuticals is due to protein film formation on the inner tubing surface followed by rupture of the film by the roller movement. Protein adsorption can be prevented by addition of surfactants as well as by increasing the hydrophilicity of the inner surface. Attempts based on covalent surface coating were mechanically not stable against the stress of roller movement. We successfully incorporated surface segregating smart polymers based on a polydimethylsiloxane (PDMS) backbone and polyethylene glycol (PEG) side blocks in the tubing wall matrix. For this we applied an easy, reproducible and cost-effective process based on soaking of tubing in toluene containing the PDMS-PEG copolymer. With this tubing modification we could drastically reduce protein particle formation during peristaltic pumping of a monoclonal antibody and human growth hormone (HGH) formulation in silicone and thermoplastic elastomer-based tubing. The modification did not impact the tubing integrity during pumping while hydrophilicity was increased and protein adsorption was prevented. Free PDMS-PEG copolymer might have an additional stabilizing effect, but less than 50 ppm of the PDMS-PEG copolymer leached from the modified tubing during 1 h of pumping in the experimental setup. In summary, we present a new method for the modification of tubings which reduces protein adsorption and particle formation during any operation involving peristaltic pumping, e.g. transfer, filling, or tangential flow filtration.

Bioproducts from proteins in neem seed oil meals

AbstractExtraction of oil from Azadirachta indica generates oil cake (meal) containing proteins and carbohydrates. The proteins in neem oil cake with antimicrobial and antioxidant properties have been made into films and studied for their properties and potential applications. Neem oil cakes are available in large quantities at low cost but are non‐edible and have limited applications. Currently, most of the neem oil cakes are used as fertilizers. Neem oil cakes contain about 25–30% proteins and 30–40% carbohydrates, which are valuable. Proteins in the neem oil cake could be suitable for food, medical, biotechnology, and other applications. However, there are no reports on the properties or applications of proteins in neem meal. In this study, a simple alkaline process was used to extract proteins from the oil meal and the proteins obtained were converted into films. The films were crosslinked with citric acid (CA) to improve mechanical properties and stability in aqueous conditions. Neem protein films have good resistance to aqueous conditions and acceptable strength and elongation. The films have better antifungal activity than antibacterial activity. Cells (L929) were able to attach and grow on the films but at a lower rate than Dulbecco's Modified Eagle Medium (DMEM) media. Proteins in neem oil cake show potential as substitutes for the animal‐based proteins in current use. © 2022 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.