Corn Protein Zein Research Articles

Tuning the properties of plant-based whipped cream through zein nanoparticles-sodium stearate complex

The fabrication of plant-based whipped creams is proposed to reduce the high saturated fat content of regular whipped creams by using plant proteins and unsaturated oils. The lack of functionality of regular plant proteins and the absence of crystals in vegetable oils make this process challenging. Here, we hypothesize that the functionality of corn protein zein can be improved by the creation of zein nanoparticles-sodium stearate complex (ZNP-SS), and that monoacylglyceride (MAG) based oleogels can increase the solid fat content of vegetable oils. Therefore, plant-based whipped cream can be produced from oil-in-water emulsions stabilized by ZNP-SS and MAG. A serial of ZNP-SS was produced and characterized in terms of molecular interactions, wettability, and surface activity. Moreover, their ability to stabilize oil-in-water emulsions and foams in the presence or absence of MAG was evaluated. Results show that ZNP-SS complex were stabilized through electrostatic and hydrophobic interactions. An increase in the amount of sodium stearate caused an increase in hydrophilicity, which improved the interfacial properties of ZNP-SS. Corn oil-in-water emulsions were successfully stabilized by all the ZNP-SS, while only the ones with the highest amount of sodium stearate (ZNP-0.6) were able to create stable whipped creams because of the partially coalesced oil droplets in the presence of MAG.

Advances and Prospects of Prolamine Corn Protein Zein as Promising Multifunctional Drug Delivery System for Cancer Treatment.

Zein is a type of prolamine protein that is derived from corn, and it has been recognized by the US FDA as one of the safest biological materials available. Zein possesses valuable characteristics that have made it a popular choice for the preparation of drug carriers, which can be administered through various routes to improve the therapeutic effect of antitumor drugs. Additionally, zein contains free hydroxyl and amino groups that offer numerous modification sites, enabling it to be hybridized with other materials to create functionalized drug delivery systems. However, despite its potential, the clinical translation of drug-loaded zein-based carriers remains challenging due to insufficient basic research and relatively strong hydrophobicity. In this paper, we aim to systematically introduce the main interactions between loaded drugs and zein, administration routes, and the functionalization of zein-based antitumor drug delivery systems, in order to demonstrate its development potential and promote their further application. We also provide perspectives and future directions for this promising area of research.

Magnetite-sepiolite nanoarchitectonics for improving zein-based bionanocomposite foams.

Magnetic nanoarchitectures have been used to introduce multifunctionality in biopolymeric matrices. Bionanocomposite foams based on the corn protein zein were prepared for the first time using the hydrophobic properties of zein in a sequential treatment consisting of the removal of ethanol-soluble fractions, followed by the water swelling of the remaining phase and a further freeze-drying process. When this protocol is applied to zein pellets, they can be consolidated as porous monoliths. Moreover, it is possible to incorporate diverse types of inorganic nanoparticles in the starting pellet to produce the bionanocomposite foams. In particular, the preparation of superparamagnetic foams has been explored using two approaches: the direct incorporation of magnetite nanoparticles in a ferrofluid by impregnation in the foams, and the application of the foaming process to mixtures of zein with magnetite nanoparticles alone or previously assembled into sepiolite clay fibers. The first methodology leads to the production of inhomogeneous foams, while the use of magnetite nanoparticles and better Fe3O4-sepiolite nanoarchitectured materials as fillers results in more homogeneous materials with improved water stability and mechanical properties, offering superparamagnetic behavior. The resulting multifunctional foams have been tested in adsorption processes using the herbicide 4-chloro-2-methylphenoxyacetic acid as a model pollutant, confirming their potential utility in decontamination applications in open waters as they can be easily recovered from the aqueous medium using a magnet.

3D Printing of Mechanically Resistant Poly (Glycerol Sebacate) (PGS)‐Zein Scaffolds for Potential Cardiac Tissue Engineering Applications

Due to the limited regenerative capacity of the natural human myocardium, 3D printing of the cyclic polyester poly (glycerol sebacate) (PGS) offers a promising alternative to produce scaffolds (cardiac patches) for cardiac tissue engineering. Since the 3D printability and subsequent thermal crosslinking of pure PGS without any modification or additives are challenging, a PGS‐zein‐salt‐based printing process is developed in this work by mixing PGS pre‐polymer with ground and sieved sodium chloride particles and additionally with different amounts of the corn protein zein. The resulting inks show excellent printability and high shape fidelity both during the printing process and after thermal crosslinking. Chemical analysis indicates the successful integration of zein into the PGS backbone. Mechanical characterization shows the anisotropic behavior of the structure in the alternating printing direction. Subsequent biological assessments reveal no cytotoxic effects on C2C12 cells, rendering the developed PGS‐zein combination a suitable material for 3D printing of cardiac patches.

Design and characterization of ellagic acid-loaded zein nanoparticles and their effect on the antioxidant and antibacterial activities

Ellagic acid (EA) has demonstrated remarkable antioxidant and antimicrobial activities. The corn protein zein is a natural biopolymer whose biological and functional properties encourage its use to improve therapeutic nano drug delivery systems. In this study, we aimed to design and characterize EA-loaded zein nanoparticles and to evaluate the impact of nanoencapsulation in the antioxidant and antibacterial properties. The nanoparticles were produced by nanoprecipitation and evaluated in terms of morphology, size, polydispersity, zeta potential, encapsulation efficiency and drug loading. The chemical interactions between EA and zein were studied by FTIR, 1H STD-NMR and Fluorescence spectroscopy. Antioxidant activity was quantified using the DPPH and ABTS radical scavenging methods, while antimicrobial activity was determined in terms of inhibitory, bactericide and antibiofilm assays against Staphylococcus aureus and Pseudomonas aeruginosa. EA-loaded zein nanoparticles were spherical, non-aggregated, below 370 nm and positively charged. Selected nanoparticles showed relevant inhibitory and bactericide activity against S. aureus and P. aeruginosa (MIC < 72 µg/mL). The antioxidant activity (IC50) for the nanoencapsulated EA were 56.02 µg/mL and 136.6 µg/mL in the DPPH and ABTS assays, respectively. Furthermore, EA nanoparticles were found to be efficient in reducing S. aureus and P. aeruginosa biofilms by 60 and 30%, respectively. The 1H STD-NMR, FTIR and Fluorescence combined analyses confirmed the interaction between EA and zein, which could explain the enhancement found in the biological activities studied, as the active phenolic groups of this molecule are likely to become more accessible after the entrapment of EA in the formed zein nanoparticles. From this we can conclude that nanoencapsulation of EA boosted its antioxidant and antibacterial activities; this offers a potential strategy against free radicals as well as preventive and treatment option for infections related to Gram-positive and Gram-negative bacteria.

Manuka Honey and Zein Coatings Impart Bioactive Glass Bone Tissue Scaffolds Antibacterial Properties and Superior Mechanical Properties

The combination of traditional herbal medicine (phytotherapeutic agents) with bioactive glasses is a promising strategy to generate advanced scaffolds for bone tissue engineering (BTE). An old remedy used for wound care since ancient times is honey. The antioxidant, antimicrobial and antibacterial properties of Manuka honey, in particular, make it an attractive substance for application in BTE scaffolds to prevent infections and biofilm formation. In this study 45S5 bioactive glass-based scaffolds produced via the foam replica technique were coated with corn protein zein and Manuka honey with two purposes: to improve the mechanical properties of the brittle scaffolds and to impart antibacterial properties. The morphology and chemical composition of the coated scaffolds were characterized with scanning electron microscopy and Fourier transform infrared spectroscopy, respectively, demonstrating the presence of Manuka honey in the coating. The release of the honey was quantified via ultraviolet-visible spectrophotometry; moreover, the antibacterial activity against Staphylococcus aureus was evaluated via colony-forming units counting, reduction of Alamar blue and turbidity measurements. Our findings suggest the effective combination of Manuka honey and bioactive glass, adding one more system to the novel family of bioactive glass scaffolds functionalized with phytotherapeutic agents.

Zein-layered hydroxide biohybrids: strategies of synthesis and characterization.

This work constitutes a basic study about the first exploration on the preparation of biohybrids based on the corn protein zein and layered metal hydroxides, such as layered double hydroxides (LDH) and layered single hydroxides (LSHs). For this purpose, MgAl layered double hydroxide and the Co2(OH)3 layered single hydroxide were selected as hosts, and various synthetic approaches were explored to achieve the formation of the zein-layered hydroxide biohybrids, profiting from the presence of negatively charged groups in zein in basic medium. Zein-based layered hydroxide biohybrids were characterized by diverse physicochemical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/differential thermal analysis (TG/DTA), solid state 13C cross-polarization magical angle spinning nuclear magnetic resonance (CP-MAS NMR), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), etc., which suggest that the different synthesis procedures employed and the anion located in the interlayer region of the inorganic host material seem to have a strong influence on the final features of the biohybrids, resulting in mixed, single intercalated, or highly exfoliated intercalated phases. Thus, the resulting biohybrids based on zein and layered hydroxides could have interest in applications in biomedicine, biosensing, materials for electronic devices, catalysis, and photocatalysis.

Design and mechanistic understanding of graphene oxide reinforced zein nanocomposites with improved mechanical, barrier and thermal properties

Graphene oxide (GO)-based zein nanocomposite films with superior mechanical, barrier and thermal properties were fabricated by incorporating GO nanoparticles into corn protein zein (Z), through the solvent casting process. The study offers a mechanistic understanding of the effect of graphene oxide nanofiller on the physicochemical properties of zein. TEM of the zein–graphene oxide (Z–GO) nanocomposites showed uniform dispersion of GO sheets up to 1%GO loading. Mechanisms for Z–GO nanocomposite formation through covalent and noncovalent bonding are developed based on FTIR, FT-Raman and DSC results. At only 3% loading, the Young’s modulus of a nanocomposite film increased by 300% and tensile strength increased by 80%. The increases in mechanical property improvements are accompanied by surface roughness increases as indicated by AFM studies. Even though GO is hydrophilic, the Z–GO nanocomposite films showed hydrophobic tendencies. The amount and degree of exfoliation of GO as well as the relative orientation of GO nanoparticles within the zein film all play an important role in the physical property changes of the film. The films became less permeable with increasing amounts of GO addition, as shown by water vapor permeability tests. GO increased thermal stability as shown by TGA.

Electrospun water-stable zein/ethyl cellulose composite nanofiber and its drug release properties

A simple and cost-effective way to prepare water-stable zein-based nanofibers for potential drug delivery was presented in this article. Corn protein zein was co-electrospun with hydrophobic ethyl cellulose. Indomethacin, as a model drug, was incorporated in situ into the composite nanofibers. Scanning electron microscopy and element mapping revealed the morphologies of drug-loaded nanofibers and drug distribution, respectively. Fourier transform infrared spectra confirmed the physical blending among the components. Differential scanning calorimetry and X-ray diffraction demonstrated the physical state of drug and polymers in the nanofiber matrix. The composite nanofibers showed a sustained diffusion-controlled release according to the results of in vitro dissolution tests.

Simultaneous transfer of noble metals and three-dimensional micro- and nanopatterns onto zein for fabrication of nanophotonic platforms

In this paper, we report a method to manufacture green nanophotonic sensors made of corn protein zein. The method is direct transfer of three-dimensional metallic (gold and silver) nanostructures onto biodegradable zein films. We have transferred both micro-scale and nano-scale structures with several geometries. Inverted and positive pyramid structures, with 2 μm by 2 μm square base, nanopores, and nanopillars with an approximately 250 nm diameter were successfully transferred onto zein along with 200- and 80-nm-thick gold layers onto pyramids and nanopillars/pores, respectively. Rhodamine 6G was used as a model molecule for surface-enhanced Raman spectroscopy (SERS) measurements, and it was found that the inverted pyramid gold zein sensors had the highest enhancement factor, compared to the other zein sensors. The novel zein sensor platform we developed has the potential to serve as a biodegradable SERS platform for applications in agricultural, medical, and food analysis purposes.

Novel electrospun poly(glycerol sebacate)–zein fiber mats as candidate materials for cardiac tissue engineering

The application of a cardiac patch made of biodegradable polymer is a novel approach in regenerative therapies for infarcted cardiac tissue and aims to deliver healthy and functional cells on a mechanically supporting matrix to the damaged area of the myocardium. In this study a novel type of tissue engineered cardiac construct based on poly(glycerol sebacate) (PGS) blended with the corn protein zein was developed. Bead free electrospun PGS–zein fibers were fabricated using acetic acid as a benign solvent. In vitro degradation studies in PBS revealed a physicochemically stable system over a 28day period showing only a slight drop in pH after 28days. The results indicate that the novel PGS–zein fibrous structures are attractive biomaterials which can be valuable for cardiac patch applications thus warranting their further investigation in vitro and in vivo.

Controlled Release from Zein Matrices: Interplay of Drug Hydrophobicity and pH.

PurposeIn earlier studies, the corn protein zein is found to be suitable as a sustained release agent, yet the range of drugs for which zein has been studied remains small. Here, zein is used as a sole excipient for drugs differing in hydrophobicity and isoelectric point: indomethacin, paracetamol and ranitidine.MethodsCaplets were prepared by hot-melt extrusion (HME) and injection moulding (IM). Each of the three model drugs were tested on two drug loadings in various dissolution media. The physical state of the drug, microstructure and hydration behaviour were investigated to build up understanding for the release behaviour from a zein based matrix for drug delivery.ResultsDrug crystallinity of the caplets increases with drug hydrophobicity. For ranitidine and indomethacin, swelling rates, swelling capacity and release rates were pH dependent as a consequence of the presence of charged groups on the drug molecules. Both hydration rates and release rates could be approached by existing models.ConclusionThe drug state and pH dependant electrostatic interactions are hypothesised to influence release kinetics. Both factors can potentially be used to influence release kinetics release, thereby broadening the horizon for zein as a tuneable release agent.Electronic supplementary materialThe online version of this article (doi:10.1007/s11095-015-1818-8) contains supplementary material, which is available to authorized users.

Solubility of the Corn Protein Zein in Imidazolium-based Ionic Liquids

The solubility of the corn protein zein is measured gravimetrically from 30 to 60 °C in seven imidazolium-based ionic liquids and three conventional solvents, acetic acid, 70 vol % aqueous ethanol, and 1-methylimidazole. At elevated temperatures the solubility of zein in six of the ionic liquids exceeds that of the current industry standard, 70 vol % aqueous ethanol. The ionic liquids 1-methylimidazolium acetate and 1-ethyl-3-methylimidazolium dicyanamide can dissolve 2.5 times more zein at 60 °C than 70 vol % aqueous ethanol. Single and multivariate regressions are used to model zein’s solubility as a function of common solvent properties. Solvents able to dissolve more zein have small molecular volumes, low polarities, and act as a weak hydrogen bond acceptors.

Subcutaneous injection of orally tolerated proteins in the mother disturbs embryo implantation in mice

Subcutaneous injection of orally tolerated proteins in the mother disturbs embryo implantation in mice

Correlation between viscoelasticity, microstructure, and molecular properties of zein and pennisetin melts

AbstractCereals are a large source of biopolymers, where mainly the starch is used for food and feed. A rapidly growing cereal application is the production of biofuel, mainly produced from corn in the US. The starch is fermented to ethanol leaving spent grain rich in cereal proteins as a by‐product. The corn protein zein is currently extracted on a large scale and used in, for example, material applications. Similarly, pennisetin can be extracted from pearl millet, a crop critical for food security in sub‐Saharan Africa. The formation of viscoelastic melts is crucial for (bio)plastics production and the viscoelasticity, microstructure, and molecular properties of zein and pennisetin melts were determined here. The proteins were mixed with plasticizers (polyethyleneglycol or glycerol/citric acid) to form melts. The melts displayed a phase separated microstructure with protein‐rich and plasticizer‐rich regions with distinctly separate Tgs. The pennisetin melts formed cross‐links at temperatures above 60°C, which could be related to the high content of cysteine and methionine, as compared to zein. As a consequence, pennisetin melts showed a more thermocomplex behavior than zein melts. For zein melts, the mixture of glycerol and citric acid interacted with protein in addition to being a plasticizer causing a high‐molecular weight shoulder in the molecular weight distribution. The study showed that, although both zein and pennisetin form viscoelastic melts, the choice of plasticizer strongly affects both melt structure and physical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Oil-in-water Pickering emulsions stabilized by colloidal particles from the water-insoluble protein zein

Few fully natural and biocompatible materials are available for the effective particle-stabilization of emulsions since strict requirements, such as insolubility in both fluid phases and intermediate wettability, need to be met. In this paper, we demonstrate the first use of water-insoluble proteins, employing the corn protein zein as a representative of this family, as effective particle-stabilizers of oil-in-water emulsions of natural oils and water. For this purpose, we synthesized zein colloidal particles through an anti-solvent precipitation procedure and demonstrated their use in the formation of stable oil-in-water Pickering emulsions as a function of particle concentration, pH and ionic strength. We confirmed that the wetting properties of zein, studied as a function of pH and ionic strength, strongly favor interfacial particle adsorption with oil-in-water three-phase contact angles θow close to 90°. We found that unmodified zein colloidal particles can produce stable, surfactant-free o/w emulsions with droplet sizes in the range 10–200 μm under experimental mixing conditions (2 min with Ultra Turrax homogenizer at 13500 rpm) at pH above and below the isoelectric point of zein, for low to moderate ionic strengths (1–10 mM). Under conditions where the particle volume fraction is low (<0.2 wt%) or at low pH, the resulting emulsions are not stable against coalescence. At a higher ionic strength, the zein particles have a tendency to aggregate and the resulting emulsions flocculate, forming an emulsion–gel phase.

Effect of zein on biodegradable inserts for the delivery of tetracycline within periodontal pockets

Treatment with antibiotics within the periodontal pocket against bacterial infections represents a useful and adjunctive tool to conventional therapy for healing and teeth preservation. With this function in view, an implantable, tetracycline delivery device for the treatment of periodontal disease was developed. The aim of this study was to develop biodegradable, tetracycline-loaded microparticles made of two polymers: PLGA and zein which were compressed into monolithic devices. In this polymer delivery system, the encapsulation efficiency, release characteristics, drug-polymer interaction, and antibacterial activity of loaded drug were investigated. The interaction of tetracycline with the corn protein zein was studied by nuclear magnetic resonance (NMR), Fourier transform infrared, and X-ray diffraction. The hydrophobic interaction of tetracycline with zein in the formulations was deduced from the NMR studies, whereas X-ray diffraction studies showed a new crystalline state of the drug in the presence of the protein. Zein was not denatured by preparation of inserts. Sustained release of tetracycline was obtained, and the proportion of zein in the inserts had a great impact on the drug release. Finally, an effective tetracycline release from inserts against Staphylococcus aureus was achieved over 30 days. In conclusion, the PLGA:zein delivery system described in this study was found to be effective in controlled delivery of tetracycline, and hence may be suitable for intra-pocket delivery of antimicrobial agents in the treatment of periodontitis.

Quantitative Structure‐Retention Relationship Study on the Binding of Organic Solvents to the Corn Protein, Zein

The strength and the character of the binding of 12 organic solvents to the corn protein zein were determined by high performance liquid chromatography. The relationship between the physicochemical parameters and binding characteristics of solvents was elucidated by canonical correlation analyses (CCA). As the number of physicochemical parameters was higher than that of our observations, three empirical methods have been employed for the preselection of variables exerting a marked impact on the binding characteristics. Calculations established that the binding of solvents to the protein is of mixed characters involving hydrophobic and electrostatic interactive forces. Sterical correspondence between the interacting molecules and molecular substructures also influence the binding of solvents to zein. The use of different preselection methods resulted in similar but not identical relationships.

Effect of pH and salts on the binding of free amino acids to the corn protein zein studied by thin-layer chromatography

The interaction of free amino acids with the corn protein zein was studied by thin-layer chromatography carried out on cellulose layers covered with zein and the effect of pH and salts on the strength of interaction was elucidated. Only the binding of Arg, His, Lys, Orn and Trp to zein was verified, other amino acids were not retained. Retention of Arg, His, Lys and Orn decreased linearly with increasing concentration of salts the mobile phase indicating the hydrophilic character of amino acid-zein interaction. Both alkaline and acidic pH influenced the strength of binding. Principal component analysis indicated the different character of the influence of pH and salts on the interaction. The results suggest that these amino acid residues may account for the binding of other peptides and proteins to zein.

TLC Study of the Binding of Nonionic Surfactants to the Corn Protein Zein

The binding of 18 nonionic surfactants with various lengths of apolar ethylene oxide chains to the corn protein zein was studied by thin‐layer chromatography (TLC) carried out on alumina layers covered with zein, and the effect of methanol, monovalent cations, and pH on the strength and selectivity of interaction was elucidated by using the spectral mapping technique and stepwise regression analysis. The binding of surfactants to zein has been demonstrated. It has been established that the number of hydrophilic ethylene oxide units in the surfactant molecule exerts the highest influence on the strength of interaction, and that the role of methanol and salt concentration is of secondary importance. The character of the cation and pH influenced both the strength and selectivity of the surfactant–zein interaction.