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A series of konjac glucomannan (KGM)/zein blend films were successfully prepared with zein in proportions 0–30%. The hydrophobicity of blend films were significantly stronger than pure KGM film, indicated by increased contact angle, swelling and solubility properties, and moisture absorption. Moreover, other properties including mechanical, thermal, water vapor and oxygen barrier were also found to be increased. FTIR indicated that hydrogen bond interactions and Maillard reaction occurred between KGM and zein molecules, and microstructural observations indicated that the aggregated zein was homogeneously dispersed in the KGM continuous matrix. However, these zein aggregations were larger with increased proportion of zein, leading to weakened molecular interactions with zein proportion >10%. A mixing ratio of KGM:zein = 9:1 was suggested to provide best film properties. This research offers an alternative improvement for KGM-based biodegradable films. [ABSTRACT FROM AUTHOR]

Edible films (EFs) have gained great interest due to their ability to keep foods safe, maintaining their physical and organoleptic properties for a longer time. The aim of this work was to develop EFs based on a chitosan-zein mixture with three different essential oils (EOs) added: anise, orange, and cinnamon, and to characterize them to establish the relationship between their structural and physical properties. The addition of an EO into an EF significantly affected (p < 0.05) the a* (redness/greenness) and b* (yellowness/blueness) values of the film surface. The EFs presented a refractive index between 1.35 and 1.55, and thus are classified as transparent. The physical properties of EFs with an added EO were improved, and films that incorporated the anise EO showed significantly lower water vapor permeability (1.2 ± 0.1 g mm h-1 m-2 kPa-1) and high hardness (104.3 ± 3.22 MPa). EFs with an added EO were able to inhibit the growth of Penicillium sp. and Rhizopus sp. to a larger extent than without an EO. Films' structural changes were the result of chemical interactions among amino acid side chains from zein, glucosamine from chitosan, and cinnamaldehyde, anethole, or limonene from the EOs as detected by a Raman analysis. The incorporation of an EO in the EFs' formulation could represent an alternative use as coatings to enhance the shelf life of food products. [ABSTRACT FROM AUTHOR]

Zeins, storage proteins from maize, are suitable for making biobased thermoplastic materials. The rheological behavior of a commercial zein plasticized with 20 w% glycerol was studied in the molten state by steady-state flow experiments in extrusion conditions and oscillatory rheometry. For low residence times, a shear-thinning viscoelastic behavior was observed, with G″ exceeding G′. After 300 s at 130 °C, the complex viscosity | η | = 7 × 10 ω was found to be similar to that of thermoplastic polymer melts used in fused deposition modeling. However, the ratio between the exponents of the power laws describing G′( ω) and G″( ω) did not meet the typical value of 2 for entangled polymer melts. Moreover, for longer residence times, the viscosity increased and a gelation phenomenon was observed with a crossing over of G′( ω) and G″( ω). Gel times ranged from 6000 s at 120 °C to 1700 s at 150 °C. The evolution of the macromolecular structure assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high-performance size exclusion chromatography suggested that this gelation phenomenon involves various types of covalent and non-covalent cross-links. Disulfide bonds played a significant role in gelation kinetics despite a very low cysteine residue content in the protein primary structure (about 1 mol%). These results suggested that plasticized zeins initially behave like a low-viscosity non-entangled polymer melt, before cross-linking progressively led to a continuous network. [ABSTRACT FROM AUTHOR]

The aim of this study was to produce ultrafine fibers from zein incorporated with a complex of eucalyptus essential oil (EEO) and β-cyclodextrin (β-CD) with antimicrobial properties by electrospinning technique. The EEO was characterized by chemical composition and antimicrobial tests against three Gram positive and four Gram negative bacteria. The inclusion complex (IC) was prepared with β-CD and EEO by co-precipitation technique and added at different concentrations in zein polymer solution using aqueous ethanol as solvent. The morphology, thermal properties, functional groups, and antimicrobial activity against L. monocytogenes and S. aureus of the ultrafine fibers were evaluated. The composite membranes containing 24% IC exhibited a greater reduction of growth as compared to the fibers without addition of IC. For L. monocytogenes the growth reduction was 28.5% and for S. aureus it was 24.3%. The electrospun IC-β-CD/EEO composite membranes are promising for use in antimicrobial applications, such as food packaging. [ABSTRACT FROM AUTHOR]

In this study, pectin was used as coating material to form zein/caseinate/pectin complex nanoparticles through pH adjustment and heating treatment for potential oral delivery applications. The preparation conditions were studied by applying heating treatment at different pHs, either the isoelectric point of zein (pH 6.2) or caseinate (pH 4.6), or consecutively at both pHs. The particulate characteristics, including particle size, polydispersity index, and zeta potential were monitored for complex nanoparticles formed under different preparation conditions. The complex nanoparticles generally exhibited particle size smaller than 200 nm with narrow distribution, spherical shape, and strong negative charge. Fourier transform infrared and fluorescence spectroscopy revealed that hydrophobic interactions and hydrogen bonds were involved in the formation of complex nanoparticles, in addition to electrostatic interactions. Fresh colloidal dispersion and freeze-dried powders varied in their morphology, depending on their preparation conditions. Our results suggested that heating pH and sequence significantly affected the morphology of complex nanoparticles, and pectin coating exerted stabilization effect under simulated gastrointestinal conditions. The present study provides insight into the formation of protein/polysaccharide complex nanoparticles under different preparation conditions. [ABSTRACT FROM AUTHOR]

In this work, we reported preparation of melatonin-loaded zein nanoparticles using the technique of solutionenhanced dispersion by supercritical CO2 (SEDS) for prolonging the release of melatonin. The influence of pressure, temperature and the ratio of melatonin and zein on the morphology, the particle size and drug loading was investigated. The release profiles of the melatonin-loaded nanoparticles were evaluated. The sizes of the most particles were less than 100 nm at most conditions examined, and the morphology had three types: rod-like, globule, and filament. The maximum drug loading of 6.9% and encapsulation efficiencies of 80.2% were obtained, respectively, under different conditions. The release speed of the melatonin in the nanoparticles is lower than both the pure one and that in the physical mixture. It displayed a near zero-order release which implied that it could be applied as a potential controlled-release drug. [ABSTRACT FROM AUTHOR]

Zein nanoparticles (NPs) were generated using continuous microfluidic antisolvent precipitation. Concentrations of ethanol and zein, flow ratio between continuous and dispersed phases, total flow rate, and chip configuration were examined for their effect on NP diameter and polydispersity index (PDI). These conditions were simulated using COMSOL Multiphysics and the diameter and PDI of NPs were correlated with physical parameters calculated by the software. Increasing zein and ethanol concentration increased NP diameter overall (p < 0.01 and 0.001, respectively). Increasing flow of continuous phase relative to dispersed phase decreased NP diameter and increased PDI overall (p < 0.001 for both). Increasing the total flow rate also decreased diameter and increased PDI overall (p < 0.001 for both). COMSOL results demonstrated that average pressure over the 3D interface representing 50% (v/v) ethanol is consistently inversely related with NP diameter and directly related to PDI (r = −0.9391 and 0.7491, respectively). [ABSTRACT FROM AUTHOR]

γ-Zein was modified by SDS or alkali combined with heating treatments in water and in 70% ethanol to change its amphipathic properties and explore the relationship between amphipathic characteristic and structure. γ-Zein water-dispersibility was dramatically increased via alkali or SDS combined with heating treatments, but their ethanol-dispersibilities were significantly different during ethanol evaporation. High both water-dispersibility and ethanol-dispersibility were found from alkali modified γ-zein while high water-dispersibility but low ethanol-dispersibility were obtained from SDS modified γ-zein, indicating that alkali modified γ-zein had better amphipathic characteristic compared with SDS modified γ-zein. Alkali modified γ-zein with higher amphipathic characteristic possessed higher structural inversion ability since it was easy to recover its native state as solvent changing from water to ethanol, contrary to SDS modified γ-zeins whose amphipathic characteristic was not improved. Moreover, the higher structural inversion ability of alkali modified γ-zein depended on the recovery capability of α-helix structure as solvent altering. [ABSTRACT FROM AUTHOR]

Simple sequential electrospinning was utilized to create a functional tri-layered nanofiber mesh that achieves time-regulated biphasic drug release behavior. A tri-layered nanofiber mesh −composed of zein and poly(vinylpyrrolidone) (PVP) as the top/bottom and middle layers, respectively − was constructed through sequential electrospinning with ketoprofen (KET) as the model drug. PVP was blended with graphene oxide (GO) to improve the drug release functionality of PVP nanofiber as well as its mechanical properties. Scanning electron microscopy confirmed that the resultant nanofibers had a linear morphology, smooth surface, and tri-layered structure. In addition, X-ray diffraction patterns, differential scanning calorimetric analyses, and Fourier transform infrared spectra verified that the drugs were uniformly dispersed throughout the nanofiber due to good compatibility between the polymer and KET induced by hydrogen interaction. In vitro release test of the tri-layered structure, each component of which had distinct release features, successfully demonstrated time-regulated biphasic drug release. Also, it was confirmed that the drug release rate and duration can be controlled by designing a morphological feature – namely, mesh thickness – which was achieved by simply regulating the spinning time of the first and third layer. This multilayered electrospun nanofiber mesh fabricated by sequential electrospinning could provide a useful method of controlling drug release behavior over time, which will open new routes for practical applications and stimulate further research in the development of effective drug release carriers. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the relationship between controlled release behaviour, swelling and initial water sorption of zein powder filled into hard gelatin capsules. Release, release rate and dissolution efficiency of various physical mixtures of zein and propranolol HCl filled into capsules were measured by dissolution testing. As the gelatin shell dissolved, zein rapidly formed a matrix, providing prolonged drug release, after an initial drug burst. Drug loading and ionic strength of the medium significantly influenced drug release. Imaging and gravimetric analysis were used to investigate matrix swelling and erosion. Zein matrices swelled like hydrophilic matrices, yet were practically non-erodible. Moreover, a strong significant positive correlation was found between matrix swelling and drug release (Pearson's correlation coefficient, r ≥ 0.9657, p -value ≤ 0.0017), suggesting that the degree of swelling governed drug release. The tensiometry test revealed that the initial ingress of media through the pores of zein powder was significantly limited by a reduction of the capillary radii of these pores, as a result of rapid polymer hydration. In conclusion, the rapid hydration of zein powder could explain the matrix formation and the controlled release observed with the capsules in the dissolution studies. Initial hydration, swelling and release behaviour were dependent on the ionic strength of the medium. [ABSTRACT FROM AUTHOR]

Periodontitis is a widespread dental disease affecting 10 to 15% of worldwide adult population, yet the current treatments are far from satisfactory. The human periodontal ligament stem cell is a promising potential seed cell population type in cell-based therapy and tissue regeneration, which require appropriate scaffold to provide a mimic extracellular matrix. Zein, a native protein derived from corn, has an excellent biodegradability, and therefore becomes a hotspot on research and application in the field of biomaterials. However, the high hydrophobicity of zein is unfavorable for cell adhesion and thus greatly limits its use. In this study, we fabricate co-electrospun zein/gelatin fiber scaffolds in order to take full advantages of the two natural materials and electrospun fiber structure. Zein and gelatin in four groups of different mass ratios (100:00, 100:20, 100:34, 100:50), and dissolved the mixtures in 1,1,1,3,3,3-hexafluoro-2-propanol, then produced membranes by electrospinning. The results showed that the scaffolds were smooth and homogeneous, as shown in scanning electron micrographs. The diameter of hybrid fibers was increased from 69 ± 22 nm to 950 ± 356 nm, with the proportion of gelatin increase. The cell affinity of zein/gelatin nanofibers was evaluated by using human periodontal ligament stem cells. The data showed that hydrophilicity and cytocompatibility of zein nanofibers were improved by blended gelatin. Taken together, our results indicated that the zein/gelatin co-electrospun fibers had sufficient mechanical properties, satisfied cytocompatibility, and can be utilized as biological scaffolds in the field of tissue regeneration. [ABSTRACT FROM AUTHOR]

A composite zein nanofibrous mat containing fish oil and ferulic acid was successfully fabricated by electrospinning. The process became more fluent and continuous by adding 30 g/L glycerol into the polymer solutions and using modified coaxial electrospinning. The average diameter of nanofibers was 440 nm. The loading capacity and encapsulation efficiency of fish oil were 20% and 94%, respectively. FTIR data demonstrated that fish oil and ferulic acid were successfully embedded into the nanofibers and there were interactions among the molecules of zein, fish oil and ferulic acid. Addition of ferulic acid into the nanofibers significantly improved the oxidative stability of encapsulated fish oil; moreover, it did not change the release behavior of fish oil. The release of encapsulated fish oil was controlled by a combination of diffusion and macromolecular chain relaxation. This composite nanofibrous mat with favorable oxidation stability and release property is potential in application as nutrition additive. [ABSTRACT FROM AUTHOR]

In this study, the effect of lauric acid and wheat gluten on physico-chemical and mechanical properties of zein-based edible films was studied. Edible films based on thermoplastic zein containing different amount of lauric acid and wheat gluten were obtained through two step procedures: melt mixing and subsequent compression molding. Results highlighted that the addition of lauric acid brought about an increase in tensile modulus and maximum stress and a decrease of water vapor permeability of zeinbased edible films. This behavior can be attributed to the increase of the hydrophobic character of the produced films. On the other hand, the addition of wheat gluten induced a reduction of water vapor permeability without affecting their mechanical properties. The best compromise between barrier and mechanical properties was observed for the thermoplastic zein-based films containing 11% and 15% of lauric acid and wheat gluten, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND Corn zein is a predominatly hydrophobic protein, forming films with relatively good water resistance. Tannic acid, especially in its oxidized form, is supposed to cross-link proteins including zein, which may be explored to further enhance the water resistance of zein films. The effects of different contents (0-8 wt%) of unoxidized and oxidized tannic acid ( uTA and oTA, respectively) on the properties of zein films at different pH values (4-9) were studied, according to central composite designs. RESULTS Increasing tannic acid contents and pH values resulted in decreased water solubility and increased tensile strength and modulus of films. The presence of tannic acid provided the films with a yellowish color and increased opacity. Paired t-tests indicated that oTA films presented higher tensile strength, lower water vapor permeability and lower water solubility than uTA films. CONCLUSION Higher tannic acid contents and pH values resulted in films with better overall physical properties, which might be ascribed to cross-linking, although the films were still not water resistant. The resulting films have potential to be used for food packaging and coating applications. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Effect of calcium ions (Ca 2 + ) on characteristics of zein-propylene glycol alginate (PGA) binary complex was studied in this work. Ca 2 + induced the formation of zein aggregates with decreased fluorescence intensity and a significant α-helix loss of zein. Zein-PGA binary complex with Ca 2 + showed the decreased dimension and the minimum size was observed at 50.0 mM Ca 2 + . Ca 2 + resulted in the formation of strong hydrogen bonds between zein and PGA, strengthened their hydrophobic interactions, and induced a new peak at the diffraction angle of 30° in the pattern of Zein-PGA binary complex. PGA fortified with Ca 2 + exhibited an overall plane-like structure, also an interwoven flat profile appeared in Zein-PGA binary complex with Ca 2 + . Three potential mechanisms were proposed to explain the morphological changes of samples after Ca 2 + addition: (i) particle-particle collision and aggregation of particles; (ii) chain-chain association and further cross-linking of associated chains; (iii) simultaneous cross-linking coupled with aggregation. [ABSTRACT FROM AUTHOR]

Active zein films with different levels of Zataria multiflora Boiss. essential oil were produced successfully. To enhance properties of this biopolymer for food packaging applications, sodium bentonite clay was used at two levels (2 and 4%). The results indicated that the addition of Z. multiflora Boiss. essential oil caused a reduction in tensile strength and Young's modulus and slight increase in the percent of elongation at break of the films. Maximum solubility in water and water vapor permeability was observed by incorporation of 10% Z. multiflora Boiss. essential oil in the zein matrix. Transmission electron microscopy micrographs of zein film were verified by the exfoliation of the layers of sodium bentonite clay in the zein matrix. Stronger films with lower water vapor permeability and water solubility were evident of good distribution of sodium bentonite clay in the zein matrix. According to the results, 2% sodium bentonite clay was selected for evaluation of nano active film properties. Water vapor permeability, UV light barrier, tensile strength, and Young's modulus values of active films were improved by incorporation of 2% sodium bentonite clay. The antibacterial activity of different contents of Z. multiflora Boiss. essential oil in vapor phase demonstrated that use of Z. multiflora Boiss. essential oil in the liquid phase was more effective than in vapor phase. The antibacterial zein-based films showed that active zein film with 5 and 10% Z. multiflora Boiss. essential oil had reductions of 1.68 log and 2.99 log, respectively, against Listeria monocytogenes and 1.39 and 3.07 log against Escherichia coli. Nano active zein film containing 10% Z. multiflora Boiss. essential oil and 2% sodium bentonite clay showed better antibacterial properties against L. monocytogenes (3.23 log) and E. coli (3.17 log). [ABSTRACT FROM AUTHOR]

[Display omitted] The strategy in this work was loading Melatonin (MEL), the powerful antioxidant photosensitive molecule, in novel Pickering emulsions (PEs) stabilized by chitosan-dextran sulphate nanoparticles (CS-DS NPs) and enhanced by lecithin, for treatment of androgenic alopecia (AGA). Biodegradable CS-DS NPs dispersion was prepared by polyelectrolyte complexation and optimized for PEs stabilization. PEs were characterized for droplet size, zeta potential, morphology, photostability and antioxidant activity. Ex-vivo permeation study through rat full thickness skin was conducted with optimized formula. Differential tape stripping trailed by cyanoacrylate skin surface biopsy was executed, for quantifying MEL in skin compartments and hair follicles. In-vivo evaluation of MEL PE hair growth activity was performed on testosterone induced AGA rat model. Visual inspection followed by anagen to telogen phase ratio (A/T) and histopathological examinations were conducted and compared with marketed 5% minoxidil spray "Rogaine ®". Data showed that PE improved MEL antioxidant activity and photostability. Ex-vivo results displayed MEL PE high follicular deposition. In-vivo study demonstrated that MEL PE treated testosterone induced AGA rat group, restored hair loss and produced maximum hair regeneration along with prolonged anagen phase amongst tested groups. The histopathological examination revealed that MEL PE prolonged anagen stage, increased follicular density and A/T ratio by 1.5-fold. The results suggested that lecithin-enhanced PE stabilized by CS-DS NPs was found to be an effective approach to enhance photostability, antioxidant activity and follicular delivery of MEL. Thus, MEL-loaded PE could be a promising competitor to commercially marketed Minoxidil for treatment of AGA. [ABSTRACT FROM AUTHOR]

Zein nanoparticles were prepared by the liquid-liquid dispersion method. The particles were used as templates for growing silver nanoparticles by reduction of silver ions using gamma radiation. The dynamic light scattering and transmission electron microscopy (TEM) results indicated that the obtained zein nanoparticles have spherical shape with a homogeneous particle size distribution and an average particle size of 60 nm. The factors affecting the silver nanoparticle deposition on zein nanoparticles were studied. Among these factors, irradiation dose, silver ion concentration, and zein polymer content were evaluated. The formation of the nanocomposite was detected using UV-vis spectroscopy and TEM. The surface plasmon resonance peak was found to be sensitive to the concentration of the zein and AgNO3 solutions. A blue shift was observed as the zein content was increased, while a red shift took place upon increasing the AgNO3 concentration. The TEM imaging indicated that the silver particles are nanosized, spherical in shape and adsorbed on the surface of zein particles. The Zein/silver nancomposites were applied for the antimicrobial test against E. coli and found to have high antibacterial activity. POLYM. COMPOS., 38:E9-E15, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this study, pectin was applied as a carbohydrate-based coating to improve physicochemical stability of sodium caseinate/zein (CZ) complex protein nanoparticles. Pectin coating was achieved via a pH- and heating-induced facile electrostatic adsorption process. The effect of pectin coating was tested on two different nanoparticle structures, i.e. solid and hollow CZ nanoparticles. The inter- and intra-molecular interactions between proteins and pectin were characterized by Fourier transform infrared and fluorescence spectroscopy. Pectin coating significantly improved the stability of nanoparticles under gastrointestinal conditions, showing minimal change in particle size and polydispersity. Our results showed that pectin coating not only significantly increased the capability of protein nanoparticles to encapsulate curcumin and but also provided sustained release under gastrointestinal conditions. Pectin-coated CZ nanoparticles demonstrated exceptional stability by maintaining their morphology before and after freeze-drying. Therefore, pectin coating is an effective strategy to potentially realize practical applications of protein nanoparticles as oral delivery vehicles. [ABSTRACT FROM AUTHOR]

Zein films loaded with 5 or 10% of Zataria multiflora Boiss. essential oil (ZEO) were successfully obtained. Migration of antimicrobial carvacrol and thymol, major components of ZEO, was monitored at different temperatures and with different food simulants, and apparent diffusion was calculated. Antimicrobial properties of the films were assayed in vapour phase and liquid medium. The results showed that films containing 5% ZEO achieved reductions of 1.18 log and 1.14 log against L. monocytogenes and E. coli , respectively, and the log reduction value increased to 2.16 log and 2.65 log for films with 10% ZEO. However, the films lacked antimicrobial activity when tested in vapour phase. Finally, thin zein films loaded with 10% ZEO were successfully applied as a coating on PP bags. The effectiveness of the active bags was tested in a more complex medium than liquid bacterial growth media, that is cow's milk inoculated with the above microorganisms. This work offers a successful approach on the use of zein proteins for active food packaging. [ABSTRACT FROM AUTHOR]

Maize ( Zea mays L.) grain is an important feedstock for the ethanol-producing industry. However, little is known about the optimum grain quality for optimizing ethanol yielding efficiencies. We specifically investigated the response of ethanol yields (L Mg) to kernel hardness, and its physiological determinant endosperm zein protein profiles, as affected by genotype selection, field nitrogen (N) fertilization, and crop growth environment. We measured ethanol yield and related this to different kernel hardness indicators, kernel composition, and zein profiles. We also described changes in field ethanol yield (L ha), by taking into account the crop yield (Mg ha). Hard endosperm genotypes always yielded less ethanol than softer endosperm ones per grain mass (L Mg). Higher N fertilization rates increased kernel hardness and decreased ethanol yield (L Mg) on soft endosperm dented genotypes but had no effect on hard endosperm ones. Ethanol yield was negatively correlated with kernel density, kernel protein concentration, and Z1 and Z2 zein fractions. Within Z2, 15 kDa β-zein explained the largest ethanol yield variation generated by genotypes, N fertilizations, and growth environments. However, and although these differences were as large as 10%, ethanol field yield (L ha) was mainly driven by crop yields ( r 0.98) due to the large crop yield (Mg ha) differences observed across treatments. Together, our results helped describe the magnitude that changes in maize kernel hardness can have over ethanol yield, both through genotype selection or crop management. A particular Z2 zein protein rises as relevant for future genetic manipulations of maize ethanol yield determination. [ABSTRACT FROM AUTHOR]

Vapor deposition can directly produce ultrastable glasses which are similar to conventional glasses aged over thousands of years. The highly mobile surface layer is believed to accelerate the ageing process of vapor-deposited glasses, but its microscopic kinetics have not been experimentally observed. Here we study the deposition growth kinetics of a two-dimensional colloidal glass at the single-particle level using video microscopy. We observe that newly deposited particles in the surface layer (depth, d < 14 particles) relax via out-of-cage diffusions of individual particles, while particles in the deeper middle layer (14 < d ≲ 100 particles) relax via activation of cooperative-rearrangement regions. These cooperative-rearrangement regions are much larger, more anisotropic and occur more frequently than cooperative-rearrangement regions in the bulk (d ≲ 100 particles) or after deposition. Cooperative-rearrangement regions move towards the surface and released free-volume bubbles at the surface, while the particles within cooperative-rearrangement regions move towards the bulk, resulting in a more compact bulk glass. [ABSTRACT FROM AUTHOR]

Zein nanoparticles (ZNPs) suspended in water were produced by the antisolvent precipitation method and combined with ι-carrageenan (ι-CGN) suspended in sodium phosphate buffer in order to evaluate the ability of the negatively-charged ι-CGN to stabilize ZNPs against flocculation and gravitational separation. Physical stability of 0.01% ZNP (w/v) dispersions with 0%–0.02% ι-CGN (w/v) was observed during storage at 4 °C and during centrifugation. Colloidal properties of the particles during storage, such as hydrodynamic radius, turbidity, and ζ-potential were characterized at pH values above pH 5. At pH 5, ZNPs were present as small aggregates with an average hydrodynamic radius of approximately 500 nm, and at higher pH values these aggregated further so that the average size was greater than 1000 nm. Addition of sufficient ι-CGN to achieve a ZNP:ι-CGN weight ratio less than or equal to 10:1 prevented aggregation in the pH range of 5.25–6.75 and limited aggregation at pH 7.0 (average particle radius of 200–400 nm). Enhanced stability was attributed to the adhesion of ι-CGN to the nanoparticle surface, as the ZNPs surface charge became significantly negative with introduction of ι-CGN. These particles remained stable for up to 30 days with significantly lower turbidity and greater resistance to gravitational separation when compared to ZNPs alone. Characterization of ZNPs with an atomic force microscope showed that the particles possessed a nearly spherical geometry with a Young's modulus of ∼100 MPa, neither of which was significantly altered after addition of interactive ι-CGN. [ABSTRACT FROM AUTHOR]

In this work, a green tea extract (GTE) was encapsulated within electrosprayed protein (i.e. gelatin and zein) microparticles, and the protective ability of both systems on the green tea catechins was assessed. The microparticles (with encapsulation efficiencies ∼90 g/100 g), proved to be very effective in stabilizing the catechins during a thermal treatment at 180 °C (12 min), preserving 85–90 g/100 g of their initial catechins content, while free GTE lost almost 40 g/100 g of its catechins content. In order to assess the impact of microencapsulation in a real food system, the GTE-loaded electrosprayed microparticles were added to biscuits dough. Results showed that microencapsulation did not significantly protect during biscuit processing and emphasized the need of assessing the behaviour of microencapsulation systems in real food processing conditions. The sensorial analysis of the biscuits indicated that addition of the GTE-loaded microparticles did not impact the acceptability of the biscuits, as perceived by consumers. [ABSTRACT FROM AUTHOR]

Curcumin-loaded zein-shellac composite particles were prepared by the antisolvent co-precipitation method. The encapsulation efficiency of curcumin was significantly improved from 82.7% in zein particles to 93.2% in zein-shellac complex particles. The result of differential scanning calorimetry suggested that curcumin in the polymeric matrix was in an amorphous state. Fourier transform infrared spectroscopy analysis revealed that curcumin had non-covalently interacted with zein and shellac, mainly through hydrogen bonding and hydrophobic interaction. Aggregates in irregular shapes, with large sizes, were found by atomic force microscopy, and conglutination, integration or fusion of different entities into network structures occurred at a high level of shellac. At the mass ratio of zein to shellac of 1:1, curcumin in the complex particles exhibited improved photochemical and thermal stability. Curcumin-loaded zein-shellac complex particles allowed the controlled release of curcumin in both PBS medium and simulated gastrointestinal fluids. [ABSTRACT FROM AUTHOR]

This study investigates the effects of hazelnut skin extract powder (HEP) and α-tocopherol addition to zein coating on lipid oxidation, texture, and moisture content of roasted hazelnuts. Total phenolic content of hazelnut skin extracted with three different solvents (acetone, ethanol, methanol) under hot (50°C) and cold (29°C) conditions were determined. The highest phenolic content (652.6 mg GAE/g) was achieved by using methanol as solvent at 50°C. Uncoated and coated hazelnuts were subjected to accelerated shelf-life testing at 40°C for 5 months. Peroxide value, free acidity, K232, and K270 values of oil fraction of hazelnuts were measured at each month as indicators of oxidative rancidity. All coatings significantly reduced the investigated parameters indicating that they are all effective in prevention of oxidation. α-Tocopherol incorporated coating provided the lowest PV (1.21 meqO2/kg) and K232 (3.03) values at the end of storage period and also it has the smoothest outer surface appearance. Hardness values and moisture contents of coated and uncoated hazelnuts remained unchanged during storage. Practical applications Application of zein coating reduced the oxidative rancidity of roasted hazelnuts without producing significant changes in its color, texture, or moisture content at ambient storage conditions. Incorporation of α-tocopherol improved the coating performance while incorporation of HEP did not at the level of 0.5% (w/v). This study shows that the shelf-life of roasted hazelnuts may be enhanced by coating with zein solution containing natural antioxidant. [ABSTRACT FROM AUTHOR]

The focus of the present work was to investigate the glycosylation of zein, partial properties of the glycosylated zein (GZ) and its retarding effect on lipid oxidation of ground pork. Zein was glycosylated with chitosan (MW 1500 Da) by microbial transglutaminase, the reaction was verified by FT-IR. Under the optimized conditions, 97.48 mg of glucosamine was covalently conjugated to 1 g of zein, determined by HPLC. The solubility and the surface hydrophobicity of GZ were significantly improved. In vitro studies of GZ showed a dose-dependent scavenging activity against free radicals of DPPH, superoxide and hydroxyl radical, and the EC 50 value for DPPH radical was 1.99 μg TE/mg protein. In addition, reducing power and Fe 2+ -chelating capacity of it were 16.60 and 12.96 μg TE/mg protein, respectively. GZ resulted in low levels of thiobarbituric acid-reactive substances and peroxide value of ground pork. These results suggest that GZ is a potential natural antioxidant. [ABSTRACT FROM AUTHOR]

Various degradable biomaterials have been used to bridge injured peripheral nerve defect; however, drawbacks such as poor mechanical properties, inappropriate degradation rate, and toxic degradation products continue to limit the application of them in nerve repair. Considering the unique properties of zein, such as its biocompatibility, biodegradability and ease of fabrication, we report the use of zein conduits to repair injured rat sciatic nerves with a 10-mm defect. Three-dimensional zein conduits were designed with/without pores, and with/without microtubes including in the lumen of conduits. Zein conduit with microtubes yielded satisfactory results in sciatic function index (SFI), proximal compound muscle action potentials, density of myelinated nerve fibres and myelin thickness, which were not inferior to autograft but slightly superior to the hollow conduit at the 4th month post-implantation. The conduits degraded almost completely within two months, which was shorter than the suggested period of four months. Thus, the use of a porous conduit with microtubes inside as the guidance may play important roles in successful repair. Notably, the regulatory body will more likely approve designs employing a single component, such as the natural polymer zein. [ABSTRACT FROM AUTHOR]

The aims of this study were to investigate the effect of xanthophylls (Xan) on the colloidal property and interfacial activity of zein hydrolysate (ZH), and the influence of Xan on the colloidal delivery capacity of ZH was also studied by the construction of emulsions and colloidal particles systems. The result indicated that compared with color-free ZH (CF-ZH), ZH was more sensitive to pH and showed obvious aggregation behavior at acidic pH. ZH exhibited lower critical micelle concentration compared with CF-ZH, suggesting the higher amphiphilic characteristic of ZH. The results from interfacial activity investigations showed that ZH exhibited higher interfacial activity compared with CF-ZH, and the thickness and intensity of the interfacial layer constituted by ZH was increased as a result of the existences of Xan. Compared with CF-ZH, the emulsions stabilized by ZH possessing smaller size and higher physical stability, and the curcumin nanoparticles fabricated in ZH solutions showed higher encapsulation efficiency, smaller particle size, better monodispersity and higher zeta potential. In conclusion, the presence of Xan in ZH obviously changed the colloidal property and improved interfacial activity and colloidal delivery capacity of ZH itself, and it endowed ZH with more extensive application prospects. [ABSTRACT FROM AUTHOR]

A novel antimicrobial composite material was prepared by encapsulating orange essential oil (OEO) in zein prolamine (ZP) via the coaxial electrospinning (ES) technique. By manipulating process parameters, the morphological features of ZP/OEO fibers were modulated. Fine fibers with diameters ranging from 0.7 to 2.3 μm were obtained by regulating ZP solution concentration and process parameters during the ES process. Optimal loading capacity (LC) and encapsulation efficiency (EE) of OEO in fibrous ZP mats were determined to be 22.28% and 53.68%, respectively, and were achieved using a 35 w/v% ZP ES solution. The encapsulation of OEO was found to be reliant on ZP solution concentration (the enveloping medium). SEM analysis indicates the surface morphology of ZP/OEO electrospun fibers is dependent on ZP solution loading volume, with lower ZP concentrations yielding defective fibrous structures (for example, beaded and spindled-string like morphologies). Furthermore, this loading volume also influences OEO LC, EE, mat water contact angle and oil retention. CCK-8 assay and cell morphology assessment (HEK293T cells) indicate no significant change with electrospun ZP and ZP/OEO fibrous membranes over an 8 h period. Antimicrobial activity assessment using Escherichia coli, suggests composite nonwovens possess sterilization properties; elucidating potential application in active food packaging, food preservation and therefore sustainability. [ABSTRACT FROM AUTHOR]

This study aimed to explore the feasibility of zein as a gluten alternative in preparing sheeted doughs with rice flours containing different amylose contents (12, 19, and 26%) that were successfully slit into noodle strands. Rice-zein mixtures with lower amylose contents exhibited lower pasting parameters and the high amylose paste samples possessed more elastic properties. Higher water absorption was observed in the low amylose rice-zein mixture whereas the use of zein were effective in increasing the stability of rice dough regardless of amylose content. In case of thermal conductivity, the noodle doughs prepared with high amylose rice-zein mixture had low thermal conductivity, probably implying a long cooking time. The structure of the rice-zein noodles had a tendency to become firmer with increasing levels of amylose by showing greater breaking stress and resistance to extension that could be correlated to reduced cooking loss. [ABSTRACT FROM AUTHOR]

The present work was aimed to evaluate the potential of the gel-like Pickering emulsions (50%, v/v, oil) stabilised by zein/tannic acid (TA) complex colloidal particles (ZTPE) as a new encapsulation system of lipophilic ingredients. Compared with sodium caseinate-stabilised emulsions (SCE) and bulk oil, the better protective effects of ZTPE on the chemical stability of curcumin were observed when they suffered from UV light, and the lipid oxidation rate remarkably reduced in ZTPE. Also, the zein particle layers loaded with TA around the oil droplets can provide protection against harsh gastric environment, facilitating to slow down the release of free fatty acids (FFA) and curcumin during in vitro simulated digestion. These findings show that ZTPE have a good potential to act as an efficient encapsulating agent to protect functional ingredients from degradation and control their release during digestion, which can further improve the bioavailability of bioactive ingredients. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study investigated the cooperative antioxidative effects of sage extract (SE) and zein hydrolysates (ZH). The combination of 3 mg/ml ZH and 10 μg/ml SE exhibited a significant synergism in inhibition of the formation of thiobarbituric acid-reactive substances and provided superior protection of liposomes against oxidation. Zeta-potential results revealed that the interactions between liposomes and ZH were electrostatic interactions. Particle size determination further proved that ZH and SE added to oxidized liposomes significantly decreased the mean particle size. Confocal laser scanning microscopy revealed that when ZH was present in the liposome oxidizing system, the droplet sizes were obviously decreased compared to oxidized samples. ZH dispersed more uniformly and the interfacial membrane was more compact in the ZH-SE liposome. Transmission electron microscopy conveyed that the ZH-SE complex around the liposome particles could form a denser network structure, preventing radicals and oxidants from the approach of the liposomes. [ABSTRACT FROM AUTHOR]

Zein, a biocompatible, biodegradable macromolecule was employed for nanoencapsulation of green tea catechins by electrospraying technique. For this, the electrohydrodynamic behavior of zein solution was studied and the effective electrospraying concentration of zein was optimized. Later, the influence of nanoencapsulation and core-to-wall ratio on the gastrointestinal stability and permeability of green tea catechins were investigated. Among the various concentrations of zein studied (i.e. 1%–40% w/w), 5% w/w zein solution yielded spherical, monodisperse nanoparticles with mean diameter of 157 ± 36 nm. Nanoencapsulates with 1:50 core-to-wall ratio had highest encapsulation efficiency compared to 1:10 and 1:05 core-to-wall ratio samples. The nanoencapsulated catechins had significantly improved in-vitro gastrointestinal stability and Caco-2 cell monolayer permeability compared to unencapsulated catechins. Further, 1:50 and 1:10 samples possessed higher permeability of catechins compared to 1:05 nanoencapsulates. Hence, the study provides a one-step approach for production of green tea catechin nanoencapsulates with sustained release and enhanced permeability properties. [ABSTRACT FROM AUTHOR]

Rice flour-zein composites in a hydrated viscoelastic state were utilized to compensate for the role of wheat gluten in gluten-free sheeted dough. The use of zein above its glass transition temperature was able to form a viscoelastic protein network of non-wheat dough with rice flour. The mixing stability and development time of the rice dough were positively increased with increasing levels of zein. The protein secondary structural analysis by FTIR spectroscopy demonstrated that the rice doughs with high levels of zein showed significant increases in β-sheet structures whose intensity was almost doubled by the use of 10% zein. The use of zein at more than 5% (w/w) successfully produced gluten-free dough sheets that could be slit into thin and long noodle strands. In addition, the composites were effective in improving the rheological characteristics of gluten-free noodle strands by increasing their maximum force to extension, compared to wheat-based noodles. [ABSTRACT FROM AUTHOR]

ABSTRACT The use of traditional petroleum-based thermoplastics in food packaging applications pose an environmental hazard, as their lack of biodegradability creates waste that environmental systems are unable to cope with. To address this issue, the investigation of surface, biodegradation, and water solubility properties of the albumin and zein thermoplastic blends plasticized with glycerol and mixed with varying amounts of low-density polyethylene (LDPE) is conducted. When subjected to soil burial, albumin as a bioplastic completely biodegrades within two months, while a zein-based bioplastic is more resilient to attacks from microbes within the soil (4.34% of intial mass remains). If albumin and zein proteins are used in the production of thermoplastics in tandem with LDPE, it could be possible to produce a plastic that will naturally biodegrade over time, decreasing the environmental impact of the use of thermoplastics in medical and food packaging applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44646. [ABSTRACT FROM AUTHOR]

This study has investigated the potential use of zein protein from corn as a pharmaceutical excipient for formulation of oral controlled-release matrices. SMCC (silicified microcrystalline cellulose)-Prosolv® 90, SMCC HD-Prosolv® 90 HD, Avicel® PH 102 and Mannitol 60 were evaluated as co-excipients to improve the processability of zein powder. Zein/SMCC-Prosolv® 90 blend had the best flowability and tabletability. Tablets with tramadol hydrochloride, zein and SMCCProsolv® 90 were prepared by direct compression. Drug release from the tablets was measured by dissolution testing. The dissolution profiles obtained were compared using the dissolution efficiency (DE) and were fitted to the Korsmeyer–Peppas equation. Controlled drug release, governed by anomalous (non-Fickian) drug transport, was obtained over the test duration. Drug release rate and mechanism were dependent on formulation parameters, such as tablet hardness, zein/SMCC ratio and drug loading, as well as medium pH. Dynamics of tablets swelling correlated well with drug release rate and mechanism, with faster drug release and greater contribution of polymer relaxation being obtained at increased swelling. In conclusion, the present work has shown that zein/SMCC based matrix formulation can be used as a new platform for oral-controlled drug delivery which can be easily customized by adjusting formulation parameters. The use of this formulation could be attractive for customers and manufacturers who prefer to avoid synthetic or chemically modified excipients. [ABSTRACT FROM AUTHOR]

We synthesize colloidal zein particles using the anti-solvent precipitation method and study particle behavior at water-water interfaces. When added to phase-separating aqueous mixtures of fish gelatin and dextran, particles accumulate at the interface. In order to explain the mechanism of particle accumulation at the water-water interface, we investigate how zein particles interact with polymers (i.e. fish gelatin and dextran). We show that both polymers adsorb similarly on particle surface, which can explain why particles form contact angles close to 90°. Moreover, we show that particle accumulation is accompanied by aggregation. Those aggregates are able to arrest the late stage of the demixing process of the emulsion by the formation of a stable particle-rich layer at the water-water interface. This layer is referred as a ‘foam-like layer’ due to its morphology similar to that of a wet (non-drained) foam, and contains droplets of one phase, surrounded by particle-stabilized lamellae of the other phase. [ABSTRACT FROM AUTHOR]

A simple method for the simultaneous and trace analysis of four synthetic food azo dyes including carmoisine, ponceau 4R, sunset yellow, and allura red from some foodstuff samples was developed by combining dispersive μ-solid-phase extraction and high-performance liquid chromatography with diode array detection. Zein-modified magnetic Fe3O4 nanoparticles were prepared and used for μ-solid-phase extraction of trace amounts of mentioned food dyes. The prepared modified magnetic nanoparticles were characterized by scanning electron microscopy and FTIR spectroscopy. The factors affecting the extraction of the target analytes such as pH, amount of sorbent, extraction time, type and volume of the desorption eluent, and desorption time were investigated. Under the optimized conditions, the method provided good repeatability with relative standard deviations lower than 5.8% ( n = 9). Limit of detection values ranged between 0.3 and 0.9 ng/mL with relatively high enrichment factors (224-441). Comparing the obtained results indicated that Fe3O4 nanoparticles modified by zein biopolymer show better analytical application than bare magnetic nanoparticles. The proposed method was also applied for the determination of target synthetic food dyes in foodstuff samples such as carbonated beverage, snack, and candy samples. [ABSTRACT FROM AUTHOR]

The oral route is an attractive delivery route for the administration of DNA-based therapeutics, specifically for applications in gene therapy and DNA vaccination. However, oral DNA delivery is complicated by the harsh and variable conditions encountered throughout gastrointestinal (GI) transit, leading to degradation of the delivery vector and DNA cargo, and subsequent inefficient delivery to target cells. In this work, we demonstrate the development and optimization of a hybrid-dual particulate delivery system consisting of two natural biomaterials, zein (ZN) and chitosan (CS), to mediate oral DNA delivery. Chitosan-Zein Nano-in-Microparticles (CS-ZN-NIMs), consisting of core Chitosan/DNA nanoparticles (CS/DNA NPs) prepared by ionic gelation with sodium tripolyphosphate (TPP), further encapsulated in ZN microparticles, were formulated using a water-in-oil emulsion (W/O). The resulting particles exhibited high CS/DNA NP loading and encapsulation within ZN microparticles. DNA release profiles in simulated gastric fluid (SGF) were improved compared to un-encapsulated CS/DNA NPs. Further, site-specific degradation of the outer ZN matrix and release of transfection competent CS/DNA NPs occurred in simulated intestinal conditions with CS/DNA NP cores successfully mediating transfection in vitro. Finally, CS-ZN-NIMs encoding GFP delivered by oral gavage in vivo induced the production of anti-GFP IgA antibodies, demonstrating in vivo transfection and expression. Together, these results demonstrate the successful formulation of CS-ZN-NIMs and their potential to improve oral gene delivery through improved protection and controlled release of DNA cargo. [ABSTRACT FROM AUTHOR]

The effects of propylene glycol alginate (PGA) at different concentrations on the physical, conformational, thermal and morphological characteristics of zein particles were explored at pH 7.0. Results showed that the size of zein particles increased from nano-scale to micron-scale with the increasing proportion of PGA incorporation, consequently leading to greatly raised turbidity of zein colloidal dispersions. There was a large increase in fluorescence intensity of zein in the presence of PGA, indicating conformational change of zein. Results of X-ray diffraction and Fourier transform infrared spectroscopy revealed that the binary complex between zein and PGA was successfully generated due to the non-covalent interaction forces, mainly including hydrogen bonds and hydrophobic effects. The presence of PGA enhanced the physical and thermal stability of zein colloidal particles. The clumps and irregularly-shaped aggregates with large diameters were observed after the interaction between zein and PGA at mass ratios of 2:1 and 1:1. Findings in this work may help further understand the interaction theory between negatively charged proteins and polysaccharides and provide new insights into for the development of potential carriers for bioactive compounds in food system. [ABSTRACT FROM AUTHOR]

Zein powders were subjected to dielectric barrier discharges (DBD) cold plasma (CP) treatment, and the physicochemical and structural properties were investigated. The results indicated that CP treatment decreased the average diameter of zein micelles. It also increased the free sulfhydryl (SH) group concentration and decreased the pH of zein solutions. Significant improvement was observed in solubility of zein in both neutral and acidic water solutions after treatment. Differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) results indicated the conformation rearrangement for all treated samples. FTIR spectrum confirmed the change of secondary structure for amide I region (1600-1700 cm) after CP treatment. Furthermore, the film-forming properties of zein were also studied. It was found that the increase of CP treatment time could reinforce the tensile strength (TS) and surface hydrophilicity of zein films. It is suggested that the DBD CP treatment technology can improve the utilization and broaden the application field of zein as an effective modification method. [ABSTRACT FROM AUTHOR]

Development of viscoelastic doughs from non-wheat proteins allows for a wider range of gluten-free products. Little work has been completed to describe mechanisms of zein functionality in food systems. To identify factors responsible for dough development in zein-starch mixtures and their influence on zein bread quality, a mixture of 20% zein-80% maize starch was mixed with water and various reagents. Salts, NaSCN, NaCl, and Na2SO4 were evaluated at concentrations from 0 to 2M for their influence on the properties of zein-starch dough systems. NaSCN at low concentrations produced softer dough. Ethanol treatments produced softer more workable dough in the absence of salts. Increasing concentrations of NaCl and Na2SO4 resulted in coalescing of the proteins and no dough formation. The addition of β-ME had minimal softening effects on zein-starch dough. Specific volumes of zein-starch bread increased with decreasing NaCl addition in bread formulations. Likewise, including 5% ethanol (v/v) in the bread formula increased bread quality. [ABSTRACT FROM AUTHOR]

Zein's amphiphilic properties, film forming capability, and biodegradability make it a highly demanded polymer for fabrication of packaging materials, production of drug carrier nanoparticles, scaffolds in tissue engineering, and formation of biodegradable platforms for biosensors including microfluidic devices. Zein properties can be improved by chemical modifications, which are often analyzed with spectroscopic techniques. However, there is not a consensus on the structure of zein. For this reason, in this Review the aim is to compile the recent studies conducted on zein-based products and compare them under five main spectroscopic techniques: Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, circular dichroism (CD), X-ray diffraction (XRD) and atomic force microscopy (AFM). This Review serves as a library of recent zein studies and helps readers to have a better perception of contradictions in the literature to take their studies one step further. [ABSTRACT FROM AUTHOR]

The anti-solvent co-precipitation method was used to fabricate the zein-propylene glycol alginate (PGA) binary complex with different mass ratios of zein to PGA (20:1, 10:1, 5:1, 2:1 and 1:1) at pH 4.0. Results showed that attractive electrostatic interaction between zein and PGA occurred and negatively charged binary complex with large size and high turbidity was formed due to the charge neutralization. Hydrogen bonding and hydrophobic effects were involved in the interactions between zein and PGA, leading to the changed secondary structure and improved thermal stability of zein. Aggregates in the irregular shape with large size were obviously observed in the AFM images. PGA alone exhibited a fine filamentous network structure, while zein-PGA binary complex showed a rough branch-like pattern and the surface of “branch” was closely adsorbed by lots of spherical zein particles. Q in zein-PGA binary complex dispersions presented the improved photochemical and thermal stability. The potential mechanism of a two-step process was proposed to explain the formation of zein-PGA binary complexes. [ABSTRACT FROM AUTHOR]

Interparticle forces that govern the assembly of particles adsorbed at fluid interfaces determine the rheology and microstructure of particle laden interface. In this study, natural small molecule, tannic acid (TA), was used to modify particle-particle interactions and assembly behaviors of food grade hydrophobic protein particle (zein nanoparticle) at air-water interface. For bare zein particle (ZP), the rapid adsorption and high interparticle forces led to the low coverage and formation of large ZP aggregates at the interface. The hydrogen-bonding of TA weakened the particle hydrophobicity and thus interparticle forces at fluid interfaces. Therefore, the adsorption process and assembly rate of ZTP at the interface obviously reduced, which also provided enough time for ZTP to rearrange into orderly interfacial networks. Furthermore, the Lissajous plots of surface pressure versus deformation are used to understand the surface rheological response to large mechanical deformation in terms of interfacial microstructure. The rheological response of interface stabilized by ZTP showed strain hardening during extension and strain softening during compression. These findings indicate that the interfacial rheology and microstructure of zein particle-laden interface can be tuned by changing the TA content. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the release kinetics and antibacterial activities of curcumin (CUR) loaded in zein (zein-CUR) electrospun fibers towards Escherichia coli ( E. coli , 8099) and Staphylococcus aureus ( S. aureus , ATCC 6538). CUR was successfully loaded in zein fibers by electrospinning technique, and the encapsulation efficiency was close to 100% and the encapsulated CUR still retained its antioxidant capacity. The morphology and size of fibers strongly depended on CUR contents. The interaction between CUR and zein matrix was confirmed to be hydrogen bonding, and the addition of CUR caused a slight increase in the T g of zein matrix. The electrode process of CUR electrooxidation was diffusion-controlled and could be preceded by chemical reaction. The predominant release of CUR from fibers was Fickian diffusion, and First-order model and Hixson-Crowell model could well describe this diffusion behavior. The zein-CUR fibers showed good antibacterial activity towards S. aureus and E. coli , and the inhibition efficiency increased with the increase of CUR contents. However, the antibacterial activity towards S. aureus was better than that towards E. coli . The study displayed that the zein-CUR fibers might have potential as a promising material for antimicrobial applications to inhibit bacterial growth and propagation in active food packaging. [ABSTRACT FROM AUTHOR]