Gliadin Particles Research Articles

Biocompatible porous material templated from gliadin particle and gellan gum co-stabilized wet foam

Porous materials have gained significant attention in diverse fields due to their potential applications. This study presents a feasible method to produce biocompatible porous materials using wet foam as a template. The synergistic effects of gliadin particles (GP) and gellan gum (GG) significantly hindered the drainage of liquid and the aging of bubbles in wet foam, specifically, GPs exhibited excellent foaming capacity and provided Pickering stabilization, and GG formed a gel network within the continuous phase upon cooling facilitating the fast capture of bubbles. Besides, these wet foams exhibited exceptional stability for duration of up to 84 days after preparation. Furthermore, these GPs-GG wet foams were used as templates enabling the production of porous materials, which exhibited micron-sized porosities ranging from 84.3% to 93.4%, with average pore sizes varying from 5.0 μm to 156.9 μm. Moreover, the average pore diameter could be easily adjusted by altering the concentrations of GPs and GG. These porous materials displayed non-cytotoxic properties and demonstrated favorable mechanical performance and exceptional water absorption capacity. Furthermore, their highly open and interconnected pore structures promoted cell growth and facilitated the proliferation of HaCaT cells from the material's surface to its interior after 1 week of culture. This study thus showcases a straightforward and feasible method for fabricating macroporous materials using biocompatible components. The potential applications of these materials, particularly in the fields of cell-cultured meat, biotechnology and biomedicine, are highly promising.

Fabrication and Characterization of Resveratrol-Loaded Gliadin Particles Stabilized by Gelatin

Fabrication and Characterization of Resveratrol-Loaded Gliadin Particles Stabilized by Gelatin

Integration of physicochemical, molecular dynamics, and in vitro evaluation of electrosprayed γ-oryzanol-loaded gliadin nanoparticles

Electrospraying is a technique to improve the application and stability of bioactive compounds in food. Here, electrospraying was applied to fabricate gliadin particles incorporated γ-oryzanol. The round particles were obtained, with an average diameter of 481.56 ± 283.74 nm, from scanning electron microscopy. Simulations demonstrated how γ-oryzanol-loaded gliadin particles were unfolded in acetic acid and culminated in their globular shape under an electric field. The results also revealed that γ-oryzanol was present in gliadin particles. Moreover, there was a successful formation of particles with a homogeneous distribution and an enhanced thermostabilization of γ-oryzanol. In food simulants, γ-oryzanol demonstrated an initial burst release, followed by a subsequent, slower release that occurred gradually. Finally, MTT assays showed concentration- and time-dependent inhibitions of γ-oryzanol-loaded gliadin particles on HT-29 cells, with IC50 values of 0.47 and 0.40 mg/mL for 24 and 48 h, respectively. This study described a protocol for developing γ-oryzanol-loaded gliadin particles with enhanced stability, valuable release-behavior, and decreased HT-29 proliferation.

Fabrication and characterization of resveratrol-loaded gliadin nanoparticles stabilized by gum Arabic and chitosan hydrochloride

Resveratrol (RES)-loaded gliadin nanoparticles stabilized by gum arabic (GA) and chitosan hydrochloride (CHC) were prepared and characterized respectively. At RES/gliadin ratio of 1:8 and gliadin/GA/CHC ratio of 1:2:1, the prepared RES-loaded gliadin-GA-CHC nanoparticles had a smaller particle size and were more stable at pH 3.0–7.0 combined with better redispersibility. The dispersion of freeze-dried gliadin-GA-CHC particles showed a relatively regular shape and smaller particle size (around 300 nm) complied with high encapsulation efficiency (68.2%). The release profiles of RES in water and in simulated gastrointestinal tract showed that RES-loaded gliadin-GA-CHC nanoparticles significantly enhanced the release of RES compared with RES-loaded gliadin particles, thus increased its bioavailability. Furthermore, RES-loaded gliadin-GA-CHC nanoparticles had stronger Fe3+ reducing antioxidant power while RES-loaded gliadin-GA nanoparticles had stronger DPPH radical scavenging activity. Hydrogen bond, electrostatic interaction and hydrophobic interaction were involved in the formation of RES-loaded gliadin-GA-CHC nanoparticles. This work is of practical importance for the preparation of stable gliadin nanoparticles as delivery vehicles for nutraceuticals.

Foaming and surface rheological behaviors of gliadin particles: Effect of solvent and concentration of gliadin stock solution

The anti-solvent method was a green and facile approach to prepare water-insoluble proteins-based colloidal particles. The structure and functional properties of the resulting particles strongly depend on the preparation parameters of the anti-solvent process. Herein, two main parameters, solvent and concentration of protein stock solution, were chosen to investigate their effects on the structural, foaming, and surface rheological properties of gliadin particles. When the solvent was 70% ethanol solution (v/v), gliadin particles exhibited a uniform spherical structure. They could fast adsorb to the air/water interface and form a viscoelastic surface layer to prevent foam drainage, coalescence, and disproportionation, thus leading to impressive foamability (~250%) and high foam stability (~60 h) even the concentration of particles was very low (1.5 mg/mL). Besides, when the solvent was acetic acid, gliadin particles possessed spherical and wire-like hybrid structures. They had slower adsorption rate and weaker interaction at the interface when compared to the ethanol-based particles, resulting in poorer foam capacity and lower foam stability. The particles prepared by different solvents had evidently different nonlinear surface rheological responses. Besides, the concentration of gliadin stock solutions did not affect the foaming and surface behaviors of particles. The particle shape played a crucial role in affecting the foaming properties and surface behaviors of gliadin particles. Results imply that 70% ethanol aqueous solution is a good solvent for gliadin, which can endow strong foaming and surface rheological behaviors to gliadin particles.

Effects of ultrasound-assisted freezing on the water migration of dough and the structural characteristics of gluten components

The effects of ultrasound-assisted freezing on the freezing time and water migration of dough, and the structural characteristics of gluten components were investigated. The effects of ultrasound-assisted freezing in the whole immersion freezing process (UWF) on the freezing time were better than those of ultrasound-assisted freezing in the maximum ice crystal generation zone. The shortest freezing time was obtained at 80 W/L, and was 577 s shorter than that with traditional immersion freezing. The UWF treatment at 80 W/L significantly (p < 0.05) affected the absorption enthalpy, freezable water content and water migration of frozen dough. In UWF compared with traditional immersion freezing, the SH content of gluten, glutenin and gliadin was significantly (p < 0.05) higher, by 12.06%, 27.55% and 21.65%, respectively. The surface hydrophobicity of gluten, glutenin and gliadin in UWF treated samples significantly (p < 0.05) decreased, by 19.67%, 13.21% and 9.17%, respectively. The secondary structure of gluten components was also significantly changed by UWF. The network of gluten, the chain structure of glutenin and the gliadin particles were all changed by UWF treatment. These findings indicated that UWF is an effective method to improve the moisture distribution in dough and reduce the damage to protein molecular structure caused by freezing.

Improving stability of gliadin-based Pickering emulsions by deamidation

Deamidation was performed to enhance the ability of gliadin for use as an emulsifier for Pickering emulsion. Pickering emulsions with internal phase of 60% w/w can be fabricated using native gliadin. In comparison, stable Pickering emulsions with internal phase of 70% w/w can be prepared using deamidated gliadin with deamidation degree of 5.7%. The increased apparent viscosity and G′ of Pickering emulsions stabilized by deamidated gliadin particles indicated the rise of particle interaction at the oil-water interface and/or in the water phase. The confocal laser scanning micrographs of emulsions and scanning electron micrographs of particles confirmed the interaction of particles in the emulsions and in the water phase. The results of interaction force tests revealed that hydrophobic and hydrogen interactions were involved in the particle interaction. These results showed that deamidation can improve the hydrophobic and hydrogen interactions of gliadin particles, aiding in the Pickering emulsion preparation and stability.

Impact of deamidation on gliadin-based nanoparticle formation and curcumin encapsulation

The physicochemical properties of gliadin-based nanoparticles and mechanisms involved in the particle formation and curcumin encapsulation were investigated. The mean particle sizes and ζ-potential indicated that stable nanoparticles can be produced around pH 7–9 where native gliadin particles were unstable. The Fourier-transform infrared spectroscopy showed that deamidation can alter particle formation with more intraparticle interactions of N-terminal domain in deamidated gliadins (DG). Results revealed that hydrophobic interaction and hydrogen bond were the major driving forces for the particle formation in gliadins. The curcumin-to-protein mass ratio of 1/20 is the optimal ratio for gliadins to encapsulate curcumin with over 91% encapsulation efficiency. Curcumin loaded in DG nanoparticles showed higher thermal stability compared with native ones. Thermodynamic parameters suggested curcumin can bind with gliadin, DG with degrees of deamidation (DD) of 8.8% and 10.7% mainly through hydrogen bonding while for DG with DD of 5.7%, the main driven force was hydrophobic interaction.

A facile strategy for the modification of chitosan/gliadin composites by tannic acid

In this study, gliadin particles (GPs) prepared by an in situ method was used as fillers to construct chitosan (CS)-based biocomposite films. Tannic acid (TA) was used as the stabilizer and modifier for the CS/gliadin composites. The micrographs of composites indicated that the addition of TA into the CS/gliadin composites changed the shapes of GPs from oval to sphere and decreased the particle size of GPs in the composites. The TA could also act as a bridge to link the GPs and CS in the composites and enhance the interactions between the GPs and CS matrix. As a result, the tensile strength of CS/gliadin composites was enhanced by the addition of TA.

Improving the stability of wheat gliadin nanoparticles – Effect of gum arabic addition

Wheat gliadin nanoparticles were prepared by antisolvent precipitation, and gum arabic (GA) was added to improve the stability of the nanoparticles. Effect of pH, gliadin/GA ratio and gliadin concentration on the gliadin-GA particles were studied by turbidimetric measurement. Spinodal lines for the GA-gliadin-solvent system were built under different pH. The influences of gliadin/GA ratio and their concentrations were represented in the diagram, thus the conditions for preparing stable composite were defined. The stability of GA-coated gliadin nanoparticles (Gliadin/GA = 1:3) was further studied compared with uncoated gliadin particles. GA-coated nanoparticles had a relatively good stability at pH 4.0–7.0 and remained a relatively low particle size with the elevated ionic strengths. They also had good thermal stability at 80 °C. Moreover, the interactions between gliadin particles and GA under different pH were further investigated. Hydrogen bonding was found to be the predominant force at pH 5.0, while hydrophobic force took charge of the formation of complex at pH 7.0. The findings are of great importance for extending the current knowledge about gliadin nanoparticles coupled with polysaccharides, thus providing valuable information for the development of gliadin-polysaccharide nanoparticles as potential nano-delivery systems.

Development of antioxidant gliadin particle stabilized Pickering high internal phase emulsions (HIPEs) as oral delivery systems and the in vitro digestion fate.

In this paper, we demonstrate for the first time the use of gliadin particles to structure algal oil (rich in DHA) and to exert chemical stability against lipid oxidation via the Pickering high internal phase emulsion (HIPE) strategy. The gliadin/chitosan colloid particles (GCCPs) were effectively adsorbed and anchored at the algal oil-water interface. Concomitantly, the particle-coated droplets as building blocks constructed a percolating 3D-network framework, endowing Pickering HIPEs with viscoelastic and self-supporting attributes. In addition, Pickering HIPEs loaded with shell (HIP-curEs) or core curcumin (HIPEs-cur) were constructed to depress the oxidation of algal oil. The content of primary (lipid hydroperoxides) and secondary (malondialdehyde and hexanal) oxidation products in HIPEs was lower than that in bulk oil. The oxidative stability of HIPEs was further improved in shell and core curcumin. An in vitro gastrointestinal (GI) model was constructed to characterize the lipid digestion, lipid oxidation as well as curcumin bioaccessibility of the ingested Pickering HIPEs. Lipid oxidation in the Pickering HIPEs was retarded under GI fluids, especially in the presence of core curcumin. The free fatty acid (FFA) fraction released was below 30% for all HIPEs, reflecting that the Pickering HIPEs formed restrict the digestion of fat or oil and potentially help to fight obesity. Interestingly, this route enhanced the bioaccessibility of curcumin from only 2.13% (bulk algal oil) to 53.61% (core curcumin); in particular, it reached 76.82% for shell curcumin. These results help to fill the gap between the physicochemical performance of the gliadin particle stabilized Pickering HIPEs and their potential applications as oral delivery systems of nutraceuticals. This work opens concomitantly an attractive strategy to convert liquid oils into antioxidant soft solids without artificial trans fats, as a potential alternative for PHOs.

Reducing Water Sensitivity of Chitosan Biocomposite Films Using Gliadin Particles Made by In Situ Method.

In order to sustain rapid expansion in the field of biocomposites, it is necessary to develop novel fillers that are biodegradable, and easy to disperse and obtain. In this work, gliadin particles (GPs) fabricated through an in situ method have been reported as fillers for creating chitosan (CS)-based biocomposite films. In general, the particles tend to agglomerate in the polymer matrix at high loading (approximately >10%) in the biopolymer/particles composites prepared by the traditional solution-blending method. However, the micrographs of biocomposites confirmed that the GPs are well dispersed in the CS matrix in all CS/GPs composites even at a high loading of 30% in this study. It was found that the GPs could improve the mechanical properties of the biocomposites. In addition, the results of moisture uptake and solubility in water of biocomposites showed that water resistance of biocomposites was enhanced by the introduction of GPs. These results suggested that GPs fabricated through an in situ method could be a good candidate for use in biopolymer-based composites.

Microfluidization initiated cross-linking of gliadin particles for structured algal oil emulsions

Abstract: The interfacial covalent cross-linking of emulsions can greatly enhance their tolerance to environmental stresses, and also contribute to formation of a new class of food products (e.g., oil gel, oil powder, and capsules). Algal oil is rich in ω-3 polyunsaturated fatty acids, while heat treatment makes it particularly susceptible to oxidation. In this study, microfluidization initiated interfacial covalent cross-linking of gliadin particles to stabilize emulsion as a novel technology to facilely construct structured algal oil product without any thermal or chemical treatment. The coarse emulsions with high algal oil volume fraction ( φ oil= 50%) stabilized by acidic gliadin particles were firstly homogenized using IKA homogenizer, and then emulsions were immediately subjected to mild alkaline pH-shifting processes. Finally, microfluidization initiated cross-linking of gliadin via intermolecular disulfide bonds to prepare stable structured emulsions. The droplet size distribution, FTIR, and SDS-PAGE of emulsions clearly verified that cross-linking was initiated by hydrophobic interaction under mild alkaline conditions, and interfacial disulfide cross-linking of gliadins was triggered by microfluidization. The viscoelastic and mechanical properties of emulsions showed homogenization pressure-dependent behavior. In addition, with increasing homogenization pressure, the increased oxidative stability with reduced lipid hydroperoxides and volatile hexanal of emulsions was also observed. Facile construction of cross-linking by microfluidization may provide a novel technology platform for gliadin based delivery system or edible oil structuring with functional characteristics.

Fluorescence Spectroscopy as a Tool to Unravel the Dynamics of Protein Nanoparticle Formation by Liquid Antisolvent Precipitation

Protein-based particles are very promising colloidal systems for protection and controlled release applications in the food, cosmetics and pharmaceutical sector. One technique to produce these protein colloidal particles is liquid antisolvent precipitation (LAS). Despite the simplicity and versatility of LAS, not much is known about the protein conformational changes and interactions that are at the basis of the particle formation process. In this study, steady state fluorescence experiments using intrinsic fluorophores were evaluated as a tool to unravel the dynamics of the protein nanoparticle formation. Colloidal whey protein isolate and gliadin particles were produced by LAS. Changes in particle diameter (distribution), polydispersity index and photophysical properties of intrinsic fluorophores were monitored as a function of antisolvent concentration. By combining dynamic light scattering with photophysical data, a model of the changes occurring during particle formation and disintegration could be proposed. The results suggest that particle formation and disintegration are fully reversible processes during which the main changes in protein conformation (around the fluorescent probes) occur at the same antisolvent concentrations. In principle, steady state fluorescence measurements using intrinsic probes can indeed be used to effectively report on (part of the) conformational changes for both protein systems under study.

Encapsulation of resveratrol in biopolymer particles produced using liquid antisolvent precipitation. Part 2: Stability and functionality

Resveratrol is a polyphenol that is believed to have beneficial effects on human health. However, its low water-solubility and poor chemical stability hamper its use as a functional food ingredient. The goal of this study was to assess the effect of resveratrol encapsulation within biopolymer particles on its UV-induced isomerization and the effect of particle structure on particle stability to environmental stresses and redispersion of powdered particles. Biopolymer particles were formed by antisolvent precipitation of hydrophobic proteins (zein or gliadin) and coated with hydrophilic copolymers (pectin or sodium caseinate). The stability and functionality of bare zein and gliadin particles (0.5% (w/v) in suspension) were compared to zein and gliadin particles coated with sodium caseinate (1.0% (w/v)) or pectin (0.1% (w/v)), respectively. Resveratrol was encapsulated at a concentration of 250 mg/l and the effect of particle structure on resveratrol UV-stability was monitored. The suspensions of coated particles were physically stable after being held at temperatures up to 90 °C (30 min). Both bare protein particles and pectin coated gliadin nanoparticles aggregated when increasing the ionic strength, while sodium caseinate coated zein particle suspensions remained stable. The pH stability of the particle suspensions was related to the isoelectric point of the nanoparticles. After freeze-drying, only the sodium caseinate coated zein nanoparticles could be fully redispersed in water. All particle formulations protected resveratrol against UV-light to some extent. However, resveratrol was best protected when encapsulated in sodium caseinate-coated zein particles. In conclusion, these particles seem promising encapsulation systems to stabilize resveratrol upon supplementation to functional foods.

Encapsulation of resveratrol in biopolymer particles produced using liquid antisolvent precipitation. Part 1: Preparation and characterization

Several health-promoting effects have been ascribed to resveratrol, a polyphenol extracted from grape skins and other sources. Its utilization as a functional food ingredient, however, is compromised by its low water solubility, poor UV stability, and low oral bioavailability. The purpose of this study was to examine the possibility of encapsulating resveratrol in biopolymer particles to overcome these issues. The particles were produced by antisolvent precipitation of hydrophobic biopolymers (gliadin or zein) in the absence or presence of hydrophilic biopolymers (pectin or sodium caseinate). Bare gliadin and zein particles had mean particle diameters of 260 and 120 nm, respectively. Pectin was the best hydrophilic biopolymer for coating gliadin particles [0.1% (w/v) pectin on 0.5% (w/v) gliadin], whereas caseinate was the best for coating zein particles [1.0% (w/v) sodium caseinate on 0.5% (w/v) zein]. Resveratrol was encapsulated at a concentration of 250 mg/l with encapsulation efficiencies of 53% and 86% in coated gliadin and zein particles, respectively. Encapsulation efficiencies were higher for coated than bare particles. No covalent bonds were detected by FTIR between resveratrol and the proteins within the particles. Electron microscopy showed that bare particles had smooth surfaces with some evidence of aggregation, whereas coated particles had rougher surfaces surrounded by filaments or films, suggesting the presence of non-absorbed hydrophilic biopolymers. In conclusion, these particles seem promising encapsulation systems to enrich functional foods with resveratrol.

Gliadin-based nanoparticles: Fabrication and stability of food-grade colloidal delivery systems

There is great interest in converting gluten, a by-product from wheat starch isolation, into a value added functional food ingredient. The insolubility of monomeric gluten, i.e. gliadin, in water makes these proteins interesting materials to produce nanoparticles using liquid antisolvent precipitation. The effect of different production parameters (such as mixing speed, time, sonication parameters, gliadin concentration) on the properties of gliadin particles formed by liquid antisolvent precipitation was investigated. The produced particles were also hardened using glutaraldehyde (0–0.25%). The stability of the produced gliadin particles was investigated in different pH and salt conditions relevant for food processing and upon short term temperature treatments and isothermal long-term storage. Gliadin nanoparticles (diameter < 200 nm) could be produced, however, they had poor stability in different conditions relevant to food processing: they redissolved below pH 4.0 and flocculated near their isoelectric point (pH ≈ 6.5), at elevated salt levels, and after heat treatment (T > 40 °C for 30 min). A slight improvement in particle stability was obtained by chemical hardening (0.25% glutaraldehyde). Gliadin nanoparticles may be useful in the development of delivery systems to encapsulate, protect, target and release active ingredients during food processing or after ingestion. However, additional strategies to stabilize the particles should be explored.

Microcellular foams made from gliadin.

We have generated closed-cell microcellular foams from gliadin, an abundantly available wheat storage protein. The extraction procedure of gliadin from wheat gluten, which involves only the natural solvents water and ethanol, respectively, is described with emphasis on the precipitation step of gliadin which results in a fine dispersion of mostly spherical, submicron gliadin particles composed of myriad of protein molecules. A dense packing of these particles was hydrated and subjected to an atmosphere of carbon dioxide or nitrogen in a high-pressure cell at 250 bar. Subsequent heating to temperatures close to but still below 100 °C followed by sudden expansion and simultaneous cooling resulted in closed-cell microcellular foam. The spherical gliadin templates along with the resulting foam have been analyzed by scanning electron microscope (SEM) pictures. The size distribution of the primary particles shows diameters peaked around 0.54 μm, and the final foam cell size peaks around 1.2 μm, at a porosity of about 80 %. These are the smallest foam cell sizes ever reported for gliadin. Interestingly, the cell walls of these microcellular foams are remarkably thin with thicknesses in the lower nanometer range, thus nourishing the hope to be able to reach gliadin nanofoam.