Zein Protein Research Articles

Study on properties of TGase-induced pea protein–zein complex gels

Gel systems are widely used in the food industry. However, most plant proteins are usually not gelatinous enough for industrial producrion, so studies are needed to improve the properties of and develop new protein gels. In this study, different mass ratios of pea protein and zein (from 10:0 to 5:5) were combined to form nanoparticles using a pH-driven method, after which TG enzyme was used to induce the composite protein particles to form a gel. This study analyzed the effects of different mass ratios of different protein on enzyme-induced composite gel formation and the gel properties. The stability of the complexes protein solution was evaluated using multiple light scattering. Microrheological parameters such as the mean square displacement, elasticity index, and mesh size indicated that zein had a positive effect on gel properties. The gel strength (145.39 ± 1.34 g), water-holding capacity (93.21 ± 1.59%), and sustained release performance of the composite gel were the highest when the zein content was 20%. These effects was mainly attributed to the increase in the number of disulfide bonds and formation of new covalent bonds in the gel, which stabilized the gel structure. The structure of a complex protein and its functional properties can be regulated by controlling the protein mass ratio, providing a new approach for improving gel properties.

Genetic and molecular understanding for the development of methionine-rich maize: a holistic approach.

Maize (Zea mays) is the most important coarse cereal utilized as a major energy source for animal feed and humans. However, maize grains are deficient in methionine, an essential amino acid required for proper growth and development. Synthetic methionine has been used in animal feed, which is costlier and leads to adverse health effects on end-users. Bio-fortification of maize for methionine is, therefore, the most sustainable and environmental friendly approach. The zein proteins are responsible for methionine deposition in the form of δ-zein, which are major seed storage proteins of maize kernel. The present review summarizes various aspects of methionine including its importance and requirement for different subjects, its role in animal growth and performance, regulation of methionine content in maize and its utilization in human food. This review gives insight into improvement strategies including the selection of natural high-methionine mutants, molecular modulation of maize seed storage proteins and target key enzymes for sulphur metabolism and its flux towards the methionine synthesis, expression of synthetic genes, modifying gene codon and promoters employing genetic engineering approaches to enhance its expression. The compiled information on methionine and essential amino acids linked Quantitative Trait Loci in maize and orthologs cereals will give insight into the hotspot-linked genomic regions across the diverse range of maize germplasm through meta-QTL studies. The detailed information about candidate genes will provide the opportunity to target specific regions for gene editing to enhance methionine content in maize. Overall, this review will be helpful for researchers to design appropriate strategies to develop high-methionine maize.

Synergistic enhancement of glucagon-like peptide-1 release by γ-aminobutyric acid and L-phenylalanine in enteroendocrine cells-searching active ingredients in a water extract of corn zein protein.

This study investigated the glucagon-like peptide-1 (GLP-1)-releasing activity of an aqueous extract (ZeinS) from corn zein protein and aimed to identify the active compounds responsible for this activity. Glucagon-like peptide-1-releasing activity was evaluated using a murine enteroendocrine cell line (GLUTag). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed on purified fractions of ZeinS to identify active molecules. ZeinS stimulated more GLP-1 secretion from GLUTag cells compared to zein hydrolysate. Fractions displaying biological activity were determined by solid-phase extraction and high-performance liquid chromatography (HPLC) fractionation. Subsequent LC-MS/MS analysis identified several amino acids in the active fractions of ZeinS. In particular, γ-aminobutyric acid (GABA) exhibited significant GLP-1-releasing activity both alone and synergistically with L-phenylalanine (Phe). Moreover, ZeinS-induced GLP-1 secretion was attenuated by antagonists for the GABA receptor and calcium sensing receptor. These results demonstrate that GABA and Phe identified in ZeinS synergistically stimulate GLP-1 secretion in enteroendocrine cells.

Tuning pharmaceutically active zein-based formulations for additive manufacturing

Zein, a biopolymer from corn, was plasticized by glycerol and an Active Pharmaceutical Ingredient-Ionic Liquid (API-IL) for its melt processing at 130 °C. In order to enhance the rheological properties of the formulation for 3D printing, the ratio of glycerol to API-IL was adjusted while maintaining a consistent addition of 20% plasticizer. A 50/50 ratio allowed obtaining an initial melt viscosity suitable for extrusion-based processes, at approximately 1 kPa.s at a shear rate of 10 s−1, with a shear thinning behavior. This viscosity remained stable during a processing window of about 6 min, before zein proteins start to aggregate, leading to an apparent gelation phenomenon for long residence times. The processability of this formulation containing API-IL for the printing of tablets for potential therapeutic applications was confirmed by tests on a 3D printer. Nonetheless, in comparison to a reference formulation containing only glycerol, the printing accuracy experienced a decrease. This was ascribed to slower viscous sintering kinetics in presence of API-IL, evidenced by monitoring fusion-bonding during dynamic X-ray tomography trials carried out at Synchrotron SOLEIL.

Fabrication of depolymerized zein films via high-intensity ultrasound for ethylene adsorption packaging

The aim of the study was to prepare depolymerized zein (D-zein) films for fruit packaging. High-intensity ultrasound (HIU) treatment was employed to stretch the chemical structure of zein protein, and improve the ethylene adsorption efficiency of D-zein films. The study of circular dichroism spectra, fluorescence spectra, particle size, zeta-potential, and total sulfhydryl group content revealed that the depolymerized zein had stretched structure via a moderate HIU treatment (400 W, 15 min). The structural, mechanical, barrier properties, ethylene adsorption efficiency, and application were used to analyze the performance of the D-zein films. In all treatment groups, bananas coated with the D-zein-15 film exhibited favorable browning rate, weight loss rate, flesh hardness, and sensory properties during storage at 25 °C for 10 d. The results indicated that depolymerized zein films could improve the ethylene adsorption efficiency and effectively prolong the shelf life of bananas.

A novel polysaccharide/zein conjugate as an alternative green plastic

The flax seed cake is a waste product from flax oil extraction. Adding value to this wasted material aligns with the concept of circularity. In this study, we explored zein protein conjugation with flax mucilage for packaging material development. Although both flax mucilage and zein have excellent film-forming properties, they lack the required mechanical properties for industrial processing and are sensitive to high humidity. We present a simple and non-toxic one-pot method for developing the novel flax mucilage/zein conjugate. Where the flax mucilage undergoes oxidation to form aldehyde groups, which then react with zein's amino groups in a glycation process. The conjugates were analyzed using different techniques. The flax mucilage conjugate had a water-holding capacity of 87–62%. Increasing the zein content improved the surface smoothness of the films. On the other hand, higher levels of zein led to a significant decrease in film solubility (p < 0.05). The flax mucilage conjugate exhibited thermoplastic and elastic properties; revealing Young's modulus of 1–3 GPa, glass transition temperature between 49 °C and 103 °C and excellent processability with various industrial techniques. Showing its potential as a sustainable alternative to traditional plastics.

PBAT/corn zein ester blends: Rheology, morphology, and physicochemical properties

The demands for sustainable packaging materials have increased interest in a new class of biomass-derived and biopolymers, such as zein protein, which are renewable, biodegradable, and water-insoluble, with excellent film-forming attributes and appealing barrier properties. However, the lack of mechanical robustness and low thermal stability of zeins impose a major limitation on their direct usage as packaging materials. As a result, extensive modifications, such as plasticization and incorporation of additives, are typically required to overcome the inherent deficiencies. In this study, corn zein was esterified to graft a fatty acid chain (decanoic acid) and blended with poly(butylene adipate-co-terephthalate) (PBAT) at varying weight ratios to produce mZein/PBAT blend films via a melt extrusion process. The blends' phase morphology, rheology, thermal, mechanical and barrier properties were investigated. The fatty acid grafting on zein enabled enhanced interfacial bonding between mZein and PBAT, promoting the compatibility of the two immiscible phases in the blends. Blending modified zein with PBAT yielded balanced stiffness, strength, and elasticity without needing external compatibilizing agents. Furthermore, the oxygen permeability of the blends was shown to reduce by up to 59% compared to neat PBAT, and water vapor barrier performance was improved by 68% compared to neat mZein. These new blended mZein/PBAT films have the potential to provide an eco-friendly material that can be used in consumer bags, packaging films, and agricultural mulch films.

A reactive oxygen/nitrogen species-eliminating natural product-based nanomedicine for prevention and treatment of inflammatory liver injury

Reactive oxygen and nitrogen species (RONS) are key signaling molecules that play an important role in the progression of inflammatory diseases. Although various antioxidants have RONS scavenging properties, they are difficult to be used to cope with acute inflammation which requires inflammatory site-targeting, effective anti-inflammatory activity, and low toxicity. In this work, we developed a safe and effective nano-antioxidant ZMF formed by simply self-assembly of natural plant protein zein and natural drug mangiferin for the synergistic treatment of inflammation-related acute liver injury. ZMF could eliminate RONS, inhibit the activation of macrophages, and modulate the level of inflammatory cytokines through the synergistic effects of mangiferin and zein. In addition, in the mouse models of inflammation-related acute liver injury, ZMF showed superior efficacy in reducing inflammatory reactions. Importantly, the preliminary in vitro and in vivo experiments proved the good safety of ZMF. This study proved the remarkable anti-inflammatory activities of nanomedicine self-assembled by RONS-eliminating natural products, which could provide a reference for the green development of efficient nano-antioxidant from natural products for the treatment of inflammation-related diseases.

Formation and characterization of hollow particles with zein-WPI hybrid shell for curcumin encapsulation

Hollow particles contain the inner aqueous compartment surrounding by a shell layer. Controllable construction of the shell layer may improve the potential use of hollow particles for encapsulating polyphenols. In this study, a novel method with alkaline-heat treatment was developed to fabricate the hollow particles with a hybrid shell of zein and whey protein isolate (WPI). Hollow particles were characterized in terms of soluble proteins, size distribution, ζ-potential, hollow structure and shell hydrophobicity. WPI at 0.25% (w/v) was enough to stabilize its zein complex hollow particles at neutral condition. The size of zein-WPI hollow particles was respectively 90 and 198 nm at pH 11 and 7, with a greater portion of proteins participated in the formation of hollow particles at pH 7 than 11. The formation mechanism of hollow particles was analyzed in terms of circular dichroism, infrared spectroscopy, dissociation test, gel electrophoresis, sulfhydryl contents and amino acid analysis. Hydrophobic interactions played a dominant role in stabilizing the shell structure of zein-WPI hollow particles, while Cys, Tyr and Lys participated in the covalent interaction between zein and WPI in hollow particles. Moreover, the shell hydrophobicity decreased by the presence of WPI, which provided a suitable microenvironment for the encapsulation of curcumin at pH 7. The findings of this study shed light on the design of protein-based hollow particles for the delivery of bioactive compounds.

Zein/chitosan composite nanospheres for controlled release of fragrances

The controlled release of fragrances is critical for cosmetics industry, but most traditional fragrance carriers have some limitations. In this study, ethanol soluble protein zein was selected as the matrix to encapsulate ethanol soluble cinnamaldehyde (CA) with the addition of another natural polymer chitosan (CS), forming composite nanospheres. The zein/CS composite nanospheres showed three different structures depending on the zein/CS mass ratio. The hydrophobic interaction between CA and zein, and the formation of Schiff base between CA and CS significantly reduced its volatilization rate to the air. In addition, it was found that the loading capacity, encapsulation efficiency, controlled release property, and antibacterial activity of the CA-loaded zein/CS composite nanospheres were closely related to their structure. The nanospheres with core (zein)/shell (CS) or homogenous structure displayed long CA release time (more than 1 day) and sustained antibacterial activity against Staphylococcus aureus. Therefore, the CA-loaded zein/CS composite nanospheres are promising carriers for developing antibacterial perfumes and coatings.

Effect of protein-based nanoencapsulation on viability of probiotic bacteria under hostile conditions

ABSTRACT The present study aimed to evaluate the effect of the incorporation of protein-based nanoencapsulation on the viability and stability of probiotic Lactobacillus rhamnosus in digestion conditions and model food. In the study’s first phase, protein-based nanoparticles were prepared by the pH cycling method, and then the probiotic, Lactobacillus rhamnosus, was nano-encapsulated. Two types of proteins, namely, whey protein and zein protein, were used to encapsulate probiotics individually. The obtained nano-encapsulated probiotics were characterized by performing particle size, SEM, FTIR, and in vitro assay was performed. Then, free and nano-encapsulated probiotics were added to the model food (yogurt) and analyzed for microbiological and sensory evaluation. Nanoencapsulation with both types of proteins significantly (p < .05) improved the stability and viability of Lactobacillus rhamnosus. The particle size for whey and zein nano-encapsulated probiotics ranged between 96 and 100 nm. The encapsulation efficiency for whey and zein nanoparticles was recorded at 96% and 87%, respectively. SEM images for both zein and whey nanoparticles showed their irregular spherical structure. FTIR spectra suggested that the mechanism of entrapment involved in water-insoluble or physical properties was mostly responsible for the generated loaded nanoparticle. In vitro analysis illustrated that whey nanoencapsulation showed the highest viability in SGC and SIC, followed by zein nanoencapsulation and free probiotics showed the minimum viability. Protein nanoencapsulation also significantly affected the sensory properties of food products. Conclusively, the nanoencapsulation of probiotics using protein nanoparticles helps prolong the viability and stability of probiotics under-simulated gastrointestinal digestion conditions and in yogurt.

Effect of Zein Protein on Rheological and Hydrophobicity of Gellan Gum-based Food Packaging Film

Effect of Zein Protein on Rheological and Hydrophobicity of Gellan Gum-based Food Packaging Film

Underwater Bonding with a Biobased Adhesive from Tannic Acid and Zein Protein.

Herein are presented several adhesive formulations made from zein protein and tannic acid that can bind to a wide range of surfaces underwater. Higher performance comes from more tannic acid than zein, whereas dry bonding required the opposite case of more zein than tannic acid. Each adhesive works best in the environment that it was designed and optimized for. We show underwater adhesion experiments done on different substrates and in different waters (sea water, saline solution, tap water, deionized water). Surprisingly, the water type does not influence the performance to a great deal but the substrate type does. An additional unexpected result was bond strength increasing over time when exposed to water, contradicting general experiments of working with glues. Initial adhesion underwater was stronger compared to benchtop adhesion, suggesting that water helps to make the glue stick. Temperature effects were determined, indicating maximum bonding at about 30 °C and then another increase at higher temperatures. Once the adhesive was placed underwater, a protective skin formed on the surface, keeping water from entering the rest of the material immediately. The shape of the adhesive could be manipulated easily and, once in place, the skin could be broken to induce faster bond formation. Data indicated that underwater adhesion was predominantly induced by tannic acid, cross-linking within the bulk for adhesion and to the substrate surfaces. The zein protein provided a less polar matrix that helped to keep the tannic acid molecules in place. These studies provide new plant-based adhesives for working underwater and for creating a more sustainable environment.

Agro-Industrial Plant Proteins in Electrospun Materials for Biomedical Application.

Plant proteins are receiving a lot of attention due to their abundance in nature, customizable properties, biodegradability, biocompatibility, and bioactivity. As a result of global sustainability concerns, the availability of novel plant protein sources is rapidly growing, while the extensively studied ones are derived from byproducts of major agro-industrial crops. Owing to their beneficial properties, a significant effort is being made to investigate plant proteins' application in biomedicine, such as making fibrous materials for wound healing, controlled drug release, and tissue regeneration. Electrospinning technology is a versatile platform for creating nanofibrous materials fabricated from biopolymers that can be modified and functionalized for various purposes. This review focuses on recent advancements and promising directions for further research of an electrospun plant protein-based system. The article highlights examples of zein, soy, and wheat proteins to illustrate their electrospinning feasibility and biomedical potential. Similar assessments with proteins from less-represented plant sources, such as canola, pea, taro, and amaranth, are also described.

Zein nanoparticles as oral carrier for mometasone furoate delivery

Mometasone furoate (MF) is a synthetic glucocorticoid used clinically to treat specific inflammatory disorders including superior and inferior respiratory tract. Due to its poor bioavailability we further investigated whether nanoparticles (NPs) made of zein protein may constitute a safe and effective choice to incorporate MF. Thus, in this work, we loaded MF into zein NPs aiming to evaluate possible advantages that could result from oral delivery and extend the range of MF application such as inflammatory gut diseases. MF-loaded zein NPs presented an average size in the range of 100 and 135 nm, narrow size distribution (polydispersity index < 0.300), zeta potential of around + 10 mV and association efficiency of MF over 70%. Transmission electron microscopy imaging revealed that NPs had a round shape and presented a smooth surface. The zein NPs showed low MF release in a buffer that mimics the gastric condition (pH = 1.2) and slower and controlled MF release in the intestinal condition (pH = 6.8). The short and intermediate safety of zein NPs was confirmed assessing the incubation against Caco-2 and HT29-MTX intestinal cells up to 24 h. Permeability studies of MF across Caco-2/HT29-MTX co-culture monolayer evidenced that zein NPs modulated MF transport across cell monolayer resulting in a stronger and prolonged interaction with mucus, potentially extending the time of absorption and overall local and systemic bioavailability. Overall, zein NPs showed to be suitable to carry MF to the intestine and future studies can be developed to investigate the use of MF-loaded zein NPs to treat intestinal inflammatory diseases.Graphical abstract

4D printed tri-segment nerve conduit using zein gel as the ink for repair of rat sciatic nerve large defect

Zein has enormous potential for application in biomedical field due to biodegradation and biocompatibility, we have recently prepared zein gel as a possible 3D printing ink. Our previous studies found that the pore structure in zein material can reduce early inflammation, promote the polarization of macrophages toward the M2 phenotype, and accelerate nerve regeneration. To further explore the role of zein in nerve repair, we used 4D printing technique to create nerve conduits with zein protein gel, and designed 2 types of tri-segment conduits with different degradation rates. Structural parts printed in support baths with higher water content show faster degradation rates than those printed in support baths with lower water content. The conduits that degraded quickly at both ends and slowly in the middle (CB75-CB40-CB75) and the conduits that degraded slowly at both ends and quickly in the middle (CB40-CB75-CB40) were 4D printed, respectively. Animal experiments suggest that the CB75-CB40-CB75 conduit is better for nerve repair, which may be because its degradation pattern can match to the pattern of nerve regeneration better. Our new strategy through 4D printing indicated that fine modulation in conduit degradation can affect efficacy of nerve repair significantly.

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.

Nanoarchitectonic E-Tongue of Electrospun Zein/Curcumin Carbon Dots for Detecting Staphylococcus aureusin Milk.

We report a nanoarchitectonic electronic tongue made with flexible electrodes coated with curcumin carbon dots and zein electrospun nanofibers, which could detect Staphylococcus aureus(S. aureus) in milk using electrical impedance spectroscopy. Electronic tongues are based on the global selectivity concept in which the electrical responses of distinct sensing units are combined to provide a unique pattern, which in this case allowed the detection of S. aureus through non-specific interactions. The electronic tongue used here comprised 3 sensors with electrodes coated with zein nanofibers, carbon dots, and carbon dots with zein nanofibers. The capacitance data obtained with the three sensors were processed with a multidimensional projection technique referred to as interactive document mapping (IDMAP) and analyzed using the machine learning-based concept of multidimensional calibration space (MCS). The concentration of S. aureus could be determined with the sensing units, especially with the one containing zein as the limit of detection was 0.83 CFU/mL (CFU stands for colony-forming unit). This high sensitivity is attributed to molecular-level interactions between the protein zein and C-H groups in S. aureus according to polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS) data. Using machine learning and IDMAP, we demonstrated the selectivity of the electronic tongue in distinguishing milk samples from mastitis-infected cows from milk collected from healthy cows, and from milk spiked with possible interferents. Calibration of the electronic tongue can also be reached with the MCS concept employing decision tree algorithms, with an 80.1% accuracy in the diagnosis of mastitis. The low-cost electronic tongue presented here may be exploited in diagnosing mastitis at early stages, with tests performed in the farms without requiring specialized laboratories or personnel.

Plant-Based Alternatives to Cheese Formulated Using Blends of Zein and Chickpea Protein Ingredients.

In this study, zein protein isolate (ZPI) and chickpea protein concentrate (CPC) ingredients were used to formulate five plant-based cheese alternatives. Ingredient ratios based on protein contributions of 0:100, 25:75, 50:50, 75:25 and 100:0 from ZPI and CPC, respectively, were used. Formulations were developed at pH ~4.5, with a moisture target of 59%. Shea butter was used to target 15% fat, while tapioca starch was added to target the same carbohydrate content for all samples. Microstructural analysis showed differences among samples, with samples containing ZPI displaying a protein-rich layer surrounding the fat globules. Schreiber meltability and dynamic low amplitude oscillatory shear rheological analyses showed that increasing the proportion of ZPI was associated with increasing meltability and greater ability to flow at high temperatures. In addition, the sample containing only CPC showed the highest adhesiveness, springiness and cohesiveness values from the texture profile analysis, while the sample containing only ZPI exhibited the highest hardness. Furthermore, stretchability increased with increasing ZPI proportions. This work will help understanding of the role and potential of promising plant-protein-ingredient blends in formulating plant-based alternatives to cheese with desirable functional properties.

Scaffold Using Chitosan, Agarose, Cellulose, Dextran and Protein for Tissue Engineering-A Review.

Biological macromolecules like polysaccharides/proteins/glycoproteins have been widely used in the field of tissue engineering due to their ability to mimic the extracellular matrix of tissue. In addition to this, these macromolecules are found to have higher biocompatibility and no/lesser toxicity when compared to synthetic polymers. In recent years, scaffolds made up of proteins, polysaccharides, or glycoproteins have been highly used due to their tensile strength, biodegradability, and flexibility. This review is about the fabrication methods and applications of scaffolds made using various biological macromolecules, including polysaccharides like chitosan, agarose, cellulose, and dextran and proteins like soy proteins, zein proteins, etc. Biopolymer-based nanocomposite production and its application and limitations are also discussed in this review. This review also emphasizes the importance of using natural polymers rather than synthetic ones for developing scaffolds, as natural polymers have unique properties, like high biocompatibility, biodegradability, accessibility, stability, absence of toxicity, and low cost.