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We report a green, non-destructive, and highly effective extraction, dissolution, film casting and solidification technology for cottonseed proteins from cottonseed meals. Although cottonseed meals are protein-rich, with about 40 % of proteins, they are cheap with a price 20 % to 50 % lower than soybean meals due to their poor performance as feed and bioplastics and due to the limited efforts from the academia and industries. Our green and protective protein extraction technology provided an extraction yield of 89 % and purity of 92 % with minimal destruction to the protein backbones, better than those reported previously. Our green dissolution/casting technology provided proteins with maximized unfolding and entanglement. When cottonseed proteins were solidified to form bioplastics, our technology also enabled substantial recovery of cystine crosslinkages between protein molecules to maximize the properties of the final products. Using our technologies, cottonseed protein films from cottonseed meals have toughness higher than what have been reported in literature without adding plasticizers or reinforcement materials, therefore better property stability or shelf life. Our technology is also cost-effective and can potentially add values to the cotton industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this research, films with compressive strength and aqueous stability were developed from camelina protein (CP) for tissue engineering. Protein based scaffolds have poor mechanical properties and aqueous stability and generally require chemical or physical modifications to make them applicable for medical applications. However, these modifications such as crosslinking could reduce biocompatibility and/or degradability of the scaffolds. Using proteins that are inherently water-stable could avoid modifications and provide scaffolds with the desired properties. CP with a high degree of disulfide cross-linkage has the potential to provide water-stable biomaterials, but it is difficult to dissolve CP and develop scaffolds. In this study, a new method of dissolving highly cross-linked proteins that results in limited hydrolysis and preserves the protein backbone was developed to produce water-stable films from CP without any modification. Only 12 % weight loss of camelina films was observed after 7 days in phosphate buffer saline (PBS) at 37°C. NIH 3T3 fibroblasts could attach and proliferate better on camelina films than on citric acid cross-linked collagen films. Therefore, CP films have the potential to be used for tissue engineering, and this extraction-dissolution method can be used for developing biomedical materials from various water-stable plant proteins., (Copyright © 2013 Wiley Periodicals, Inc.)

Various natural and synthetic polymers are being explored to develop biomaterials for tissue engineering and drug delivery. Although proteins are preferable over carbohydrates and synthetic polymers, biomaterials developed from proteins lack the mechanical properties and/or biocompatibilities required for medical applications. Plant proteins are widely available, have low potential to be immunogenic and can be made into fibers, films, hydrogels and micro- and nano-particles for medical applications. Studies, mostly with zein, have demonstrated the potential of using plant proteins for tissue engineering and drug delivery. Although other plant proteins such as wheat gluten and soyproteins have also shown biocompatibility using in vitro studies, fabricating biomaterials such as nano-fibers and nano-particles from soy and wheat proteins offers considerable challenges., (Copyright © 2011. Published by Elsevier Ltd.)

This paper demonstrates that gliadin-free wheat glutenin can be an excellent biomaterial for tissue-engineering applications, better than poly(lactic acid) (PLA). Although plant proteins are more readily available than collagen and silk, limited studies have been conducted on understanding the potential of using plant proteins as biomaterials. Wheat proteins have not been used for tissue engineering due to the cytotoxicity of gliadin. In this research, wheat gluten, glutenin and gliadin were used to develop films and the mechanical properties, water stability and ability of the films to promote the attachment, growth and viability of osteoblast cells was studied in comparison to PLA films. The wheat protein films have good strength ranging from 8 to 30 MPa. Gliadin films experience about 50% weight loss whereas glutenin films have about 90% weight loss after being in water (pH 7.2) for 15 days at 37°C. Gliadin is cytotoxic and the presence of gliadin restricts the cell proliferation on wheat gluten films. However, gliadin-free glutenin films show a higher rate of proliferation of osteoblast cells than the PLA films. Wheat gluten promises to be a potential substrate for tissue engineering and other medical applications.

We report the development of a new method of alkali-catalyzed low temperature wet crosslinking of plant proteins to improve their breaking tenacity without using high temperatures or phosphorus-containing catalysts used in conventional poly(carboxylic acid) crosslinking of cellulose and proteins. Carboxylic acids are preferred over aldehyde-containing crosslinkers for crosslinking proteins and cellulose because of their low toxicity and cost and ability to improve the desired properties of the materials. However, current knowledge in carboxylic acid crosslinking of proteins and cellulose requires the use of carboxylic acids with at least three carboxylic groups, toxic phosphorous-containing catalysts and curing at high temperatures (150-185 degrees C). The use of high temperatures and low pH in conventional carboxylic acid crosslinking has been reported to cause substantial strength loss and/or undesired changes in the properties of the crosslinked materials. In this research, gliadin, soy protein, and zein fibers have been crosslinked with malic acid, citric acid, and butanetetracarboxylic acid to improve the tenacity of the fibers without using high temperatures and phosphorus-containing catalysts. The new method of wet crosslinking using carboxylic acids containing two or more carboxylic groups will be useful to crosslink proteins for various industrial applications.

Protein fibers with mechanical properties similar to those of wool and better than those of soyprotein and zein fibers have been produced from 100% wheat gluten. Wheat gluten is a low cost, abundantly available, and renewable resource suitable for fiber production. A simple production method has been developed to obtain high-quality wheat gluten fibers, and the structure and properties of the fibers have been studied. Wheat gluten fibers have breaking tenacity of about 115 MPa, breaking elongation of 23%, and a Young's modulus of 5 GPa, similar to those of wool. Wheat gluten fibers have better tensile properties than soyprotein- and casein-based biomaterials. In addition, the wheat gluten fibers have resistance similar to that of PLA fibers to water in weak alkaline and slightly lower resistance in weak acidic conditions at high temperatures.

ABSTRACT Films developed by thermoprocessing of plant proteins have better mechanical properties and are relatively inexpensive and environmentally friendly compared to casting films from solutions. Common plant proteins such as soyproteins, wheat gluten, and corn zein and proteins from lesser grown cereal crops such as peanut, barley, sunflower, and sorghum have all been injection or compression molded into films. Since plant proteins are non-thermoplastic, it is necessary to chemically or physically modify the proteins and make them thermoplastic. Extensive studies on the addition of plasticizers, pre-treatment of proteins with alkali, steam, chemical modifications such as acetylation and blending of the proteins with other biopolymers and synthetic polymers have been done to modify proteins and develop thermoplastics. Despite the extensive work, thermoplastic films obtained from plant proteins do not have the properties that can meet or exceed properties of films made from synthetic polymers. Poor water stability and brittleness are the two major limitations of plant protein films. This review presents an overview of the methods and processing conditions used to develop thermoplastic films from plant proteins and the properties of the films. A critical assessment of approaches that have been used so far, limitations of these approaches and potential considerations for future studies to overcome the current limitations have been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 729-738, 2013 [ABSTRACT FROM AUTHOR]

Two plant proteins, soyprotein and wheat gluten, and chicken feathers used to size cotton substrates provided sizing performance similar to starch and were also easily degraded in activated sludge. Sizing is an essential process to impart protection to warp yarns and increase weaving efficiency. Cotton yarns have traditionally been sized with starch, modified starch derivatives, CMC, poly vinyl alcohol (PVA), or a combination thereof along with quite a few other fiber binding ingredients. Although starch and starch derivatives are extensively used for sizing, there can be several limitations including less-than-satisfactory sizing performance and difficulties in desizing starch based size. Plant proteins such as wheat gluten, soyproteins and poultry feathers are available in large quantities at low cost and have limited industrial applications. However, these proteins are known to have excellent film-forming properties, a primary requirement for a warp size, and have also been used as adhesives. Using proteins as warp sizing agents on cotton yarns potentially could provide acceptable sizing performance and be cost-effective, as well. In this research, soyproteins, wheat gluten, and chicken feathers were studied for exploring their feasibility for sizing, desizing, biodegradability, and ability to replace starch and PVA for sizing cotton yarns. It was found that all three proteins provided similar cohesion to fibers and abrasion resistance compared to starch. Protein sizes had significantly high BOD/COD ratio compared to PVA, suggesting that the proteins are easily degradable in textile effluent treatment plants. [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate that zein-jute fiber composites developed using water plasticized zein as matrix can have substantially higher flexural and tensile properties than composites obtained using polypropylene as matrix. Zein is a plant protein that has been used to develop various types of thermoplastic products. Zein can be extracted from corn distillers dried grains (DDG) with potentially much lower cost than biopolymers in current use. However, thermoplastics developed from zein are brittle and it is necessary to use plasticizers or chemically modify zein to obtain useful zein-based products. Hydrophilic plasticizers such as glycerol that are retained in the composite after fabrication absorb moisture and considerably decrease the properties of the composites. Similarly, chemical modifications make the matrix materials expensive and/or decrease their biodegradability. In this research, we have used water to plasticize zein composites reinforced with jute fibers. Unlike plasticizers such as glycerol, water used as a plasticizer in this research evaporates during composite formation and does not affect the properties of the composites. Zein-jute composites have about 100% higher flexural strength, 82% higher tensile strength than similar PP-jute composites. The zein-jute composites have better flexural and tensile properties than PP-jute composites even at 21 °C and 90% relative humidity. Water serves as an effective plasticizer to utilize zein as a matrix for composites. [Copyright &y& Elsevier]

Abstract: This paper reports a new method of cross-linking electrospun zein fibers using citric acid as a non-toxic cross-linker to enhance the water stability and cytocompatibility of zein fibers for tissue engineering and other medical applications. The electrospun structure has many advantages over other types of structures and protein-based biomaterials possess unique properties preferred for tissue engineering and other medical applications. However, ultrafine fiber matrices developed from proteins have poor mechanical properties and morphological stability in the aqueous environments required for medical applications. Efforts have been made to improve the water stability of electrospun protein scaffolds using cross-linking and other approaches, but the current methods have major limitations, such as cytotoxicity and low efficiency. In this research electrospun zein fibers were cross-linked with citric acid without using any toxic catalysts. The stability of the cross-linked fibers in phosphate-buffered saline and their ability to support the attachment, spreading and proliferation of mouse fibroblast cells were studied. The cross-linked electrospun fibers retained their ultrafine fibrous structure even after immersion in PBS at 37°C for up to 15days. Citric acid cross-linked electrospun zein scaffolds showed better attachment, spreading and proliferation of fibroblast cells than uncross-linked electrospun zein fibers, cross-linked zein films and electrospun polylactide fibers. [ABSTRACT FROM AUTHOR]

Fibers with mechanical properties and water stability suitable for tissue engineering have been developed from soyproteins. Proteins are biocompatible and biodegradable and are preferred over synthetic polymers for medical applications. Although plant proteins are abundant and inexpensive and can be made into various types of scaffolds, very few attempts have been made to understand the suitability of using plant proteins for medical applications, especially as fibrous substrates for tissue engineering. So far, it has not been able to obtain good quality soyprotein fibers without using toxic crosslinking agents or blending soyprotein with synthetic polymers. In this research, we have developed 100% soyprotein fibers with good strength and water stability without using any external crosslinking agents. The soyprotein fibers have better wet strength than collagen fibers and are conducive to the attachment, growth, and proliferation of mouse fibroblasts. Fibers are better substrates than films for growth and orientation of cells and are therefore preferable for tissue engineering applications. Soyprotein fibers show good potential to be novel biomaterials with properties suitable for tissue engineering and other medical applications. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [ABSTRACT FROM AUTHOR]

[Display omitted] • Green technology for artificial protein fibers from sorghum distillers grains. • Fibers with properties better than that from other plant proteins or feathers. • Fibers with mechanical properties better than wool after being crosslinked. • Value addition to sorghum and its bioprocessing industry. For the first time, artificial fibers from proteins, mainly kafirin and glutelin, from sorghum distillers grains (SDG) have been developed. SDG is difficult to digest due to dense cystine crosslinkages, therefore, is a poor animal feed with much lower value than corn distillers grains. However, dense cystine crosslinkages are an advantage for fiber properties, such as mechanical properties and wet stability. Also, fibers are much more expensive than feed, hence, can add higher values to sorghum industry. Previously, only kafirin was extracted from SDG using traditional solvents for plant proteins, such as alcohol/water, acetic acid, and formic acid. However, these solvents provided kafirin with poor or no spinnability. Glutelin, another major protein in SDG, about 35% of total, had not been used for industrial applications. We developed a green and sustainable water-based system that dissolved sorghum proteins including both kafirin and glutelin and achieved desirable fiber spinnability. We also developed the green aqueous coagulation and oxidation systems to effectively solidify protein fibers after wet spinning from our aqueous spinning solution and recovered cystine crosslinkages between sorghum protein molecules. The artificial sorghum protein fibers from our total aqueous and green spinning system have mechanical properties better than soy protein fibers and regenerated feather keratin fibers. We also used the sustainable sucrose-derived aldehydes to chemically crosslink sorghum proteins. With only 2% of the crosslinker based on weight of fibers, our artificial sorghum protein fibers have mechanical properties better than that of wool. [ABSTRACT FROM AUTHOR]

Abstract: Solution cast films made from peanut proteins extracted from peanut meal and crosslinked with citric acid were found to have good dry and wet tensile properties but poor biocompatibility. Plant proteins are abundantly available, are non-immunogenic and can be used to develop films, fibers, nanoparticles and other types of materials for various applications. Previous attempts on developing films from peanut proteins have used high amounts of glycerol resulting in poor film properties. In this research, peanut proteins were made into films using 3–15% glycerol and the effect of film forming conditions on the tensile properties and thermal behavior was studied. Films were crosslinked with cytocompatible citric acid as the crosslinking agent. Ability of the crosslinked films to be used as substrates for tissue engineering was studied using mouse fibroblast cells. It was found that films developed in this research had much higher tensile strength and modulus than films previously developed from peanut proteins. Crosslinking with citric acid improved the dry and wet strengths of the films without affecting the water vapor permeability. Peanut protein films did not support the attachment and growth of mouse fibroblast cells suggesting that peanut proteins were cytotoxic. [Copyright &y& Elsevier]

For the first time, rheological behavior of soy protein isolate (SPI) solution with high concentration for fibers and films was studied. The results showed that SPI could be readily dissolved in urea/sodium sulfite aqueous system, and the SPI solution is suitable for wet spinning and film casting. The effects of concentration, temperature, and shear rates on the rheological properties of SPI solution were studied. Viscosity of SPI solution decreases with increasing temperature, which is good for the preparation of solution with high concentration and regenerated SPI fibers/films with good properties. All solution samples exhibited thixotropic behavior, which were different from traditional polymer solution for wet spinning and film casting process. Both in forward and backward measurements were carried out by the Power Law model. Under constant shear rates (80-160 s −1 ), 18 wt% SPI solution was chosen to study the dependence of viscosity on time. Second order structural kinetic model, Weltman model, first-order stress decay models with zero and none-zero equilibrium stress values were used to fit the rheological data. Among the four models, Weltman model is more appropriate to fit the thixotropic data. [ABSTRACT FROM AUTHOR]

Abstract: We show that the wheat proteins gluten, gliadin and glutenin can be compression molded into thermoplastic films with good tensile strength and water stability. Wheat gluten is inexpensive, abundantly available, derived from renewable resource and therefore widely studied for potential thermoplastic applications. However, previous reports on developing thermoplastics from wheat proteins have used high amounts of glycerol (30–40%) and low molding temperature (90–120°C) resulting in thermoplastics with poor tensile properties and water stability making them unsuitable for most thermoplastic applications. In this research, we have developed thermoplastic films from wheat gluten, gliadin and glutenin using low glycerol concentration (15%) but high molding temperatures (100–150°C). Our research shows that wheat protein films with good tensile strength (up to 6.7MPa) and films that were stable in water can be obtained by choosing appropriate compression molding conditions. Among the wheat proteins, wheat gluten has high strength and elongation whereas glutenin with and without starch had high strength and modulus but relatively low elongation. Gliadin imparts good extensibility but decreased the water stability of gluten films. Gliadin films had strength of 2.2MPa and good elongation of 46% but the films were unstable in water. Although the tensile properties of wheat protein films are inferior compared to synthetic thermoplastic films, the type of wheat proteins and compression molding conditions can be chosen to obtain wheat protein films with properties suitable for various applications. [Copyright &y& Elsevier]