Zein Fibers Research Articles

Bioactive electrospun zein fibers integrated with ZnO nanoparticles: In vitro investigations

The objective of the current study was the fabrication and characterization of electrospun zein-ZnO fibers containing various concentrations of cumin essential oil (CEO) (0, 1, 2, and 3% (v/v)). The electrospinning solution's apparent viscosity, conductivity, and surface tension were measured. Also, the electrospun's morphological, color, encapsulation efficiency, antioxidant and antimicrobial properties, thermal stability, and release kinetic were investigated. The results represented that following the increase in CEO concentration, the conductivity and surface tension of the electrospinning solution changed from 182.92 μS/cm to 145.22 μS/cm and 19.52 mN/m to 22.35 mN/m, respectively. The scanning electron microscope (SEM) revealed the homogenous and free-bead structure of electrospun fibers. Besides, the diameter of fibers enhanced with a rise in CEO concentration from 217.13 nm to 321.67 nm. The finding estimated the maximum encapsulation efficiency and loading capacity at about 95.09% and 25.65%, respectively in electrospun containing the highest concentration of CEO (3%). CEO inclusion in electrospinning fibers augmented the value of contact angle, color difference, TPC, antioxidant, and antimicrobial properties. The favorable interaction between the CEO ingredients and electrospinning fibers was confirmed through FTIR and XRD analysis. Furthermore, the incorption of CEO enhanced the thermal stability of fibers. Release kinetic in different simulant (aqueous, acidic, alkaline, and fatty) revealed that Fick's diffusion was the main release mechanism. The highest diffusion coefficient was observed in electrospun fibers containing 3% CEO in the fatty media simulant. These findings could present a new horizon into electrospinning fiber's application in various fields of medicine, tissue engineering, food, and pharmaceutical industry.

Electrospun zein fibers loaded with pomegranate flower extract: Characterization and release behavior

In the present study electro-spinning technique was used to encapsulate pomegranate flower extract (PFE) in zein fibers. The effect of PFE concentrations (0%, 5%, 10%, and 15% (v/v)) on the electrospun solution properties, such as surface tension, apparent viscosity, and electrical conductivity were investigated. These effects on various fibers properties including morphology, thermal properties, structural characteristics, morphology, antioxidant and antimicrobial activity, encapsulation efficiency (EE), and release behavior was also evaluated. The results revealed that, increasing the PFE concentration (0–15%) led to increased surface tension and electrical conductivity and decreased the apparent viscosity of the electrospinning solution. This caused an increase in the fiber diameter from 217.1 to 722.2 nm with considerable EE (92.21–96.1%) and loading capacity (LC) (12.3–36.1%). Increasing the PFE concentration increased the surface hydrophilicity (contact angle of 93.21° and 57.82° respectively for 0 and 15% PFE loaded electrospun). Field emission scanning electron microscope (FESEM) results showed that all the fibers were uniform and free of beads. Also, molecular interaction between the PFE and zein has been confirmed with Fourier transform infrared (FTIR). DSC results indicated that the thermal stability were increased with increasing PEF concentration. The study also showed that the release of the PFE was slowest in a fatty food simulant. The primary release mechanism in simulated environments was Fickian diffusion. This research demonstrated that PFE loaded zein fibers can be used successfully in drug delivery, active packaging, and cosmetic products.

Anthocyanin-rich grape pomace extract encapsulated in protein fibers: Colorimetric profile, in vitro release, thermal resistance, and biological activities

Red wine grape pomace is an important source of bioactive compounds with biological activities of interest. Grape pomace extract can be encapsulated in ultrafine fibers using the electrospinning technique. Encapsulation is used to increase stability and protect the phenolic compounds in the extract. In this study, zein fibers were developed for encapsulation of grape pomace extract (0 %, 5 %, 10 %, and 15 % w/w). The extract was evaluated for colorimetric profile, whereas the ultrafine zein fibers carrying the extract were assessed for morphology, loading capacity, in vitro release profile, thermal and thermogravimetric properties, thermal resistance, hydrophilicity, and antioxidant and antimicrobial activities. The grape pomace extract changed color depending on pH, ranging from pink (pH 1) to yellow (pH 13 and 14). The fibers presented a smooth and uniform structure, with diameters of approximately 450 nm and a loading capacity of up to 82 %. The membranes of ultrafine fibers demonstrated hydrophilic behavior, and the in vitro release profile was dependent on the concentration of the added extract. Furthermore, the fibers were observed thermally protect the encapsulated compounds and maintain their antioxidant and antimicrobial activities. These findings indicate that the produced material has potential applications in the development of active and intelligent packaging for the food industry.

Short-Stranded Zein Fibers for Muscle Tissue Engineering in Alginate-Based Composite Hydrogels.

Cultivated meat is a nascent technology that aims to create an environmentally and animal-friendly alternative to conventional meat. Producing skeletal muscle tissue in an animal-free system allowing for high levels of myofusion and maturation is important for the nutritional and sensorial value of cultivated meat. Alginate is an attractive biomaterial to support muscle formation as it is food-safe, sustainable and cheap and can be crosslinked using non-toxic methods. Although alginate can be functionalized to promote cell attachment, limitations in its mechanical properties, including form, viscosity, and stress relaxation, hinder the cellular capacity for myogenic differentiation and maturation in alginate-based hydrogels. Here, we show that the addition of electrospun short-stranded zein fibers increased hydrogel degradation, resulting in faster compaction, improved cell-gel interaction, and enhanced alignment of bovine muscle precursor cells. We conclude that fiber-hydrogel composites are a promising approach to support optimal formation of 3D constructs, by improving tissue stability and thus prolonging culture duration. Together, this improves muscle-related protein content by facilitating myogenic differentiation and priming muscle organoids for maturation.

Electrospun zein incorporating phycocyanin and Spirulina extract: Fabrication, characterization, and potential application

Electrospinning was used to develop zein fibers containing phycocyanin and aqueous-ethanolic extract of Spirulina (AEES) for elucidating the potent packaging properties of phycocyanin and AEES on walnut samples. Morphological results revealed that using the fibers at 0.3 g/mL concentration resulted in optimal outcomes under the conditions of 15 kV, 0.5 mL/h, and 10 cm. These findings showed that phycocyanin-loaded and AEES-loaded zein fibers were similar in morphology and diameter. The encapsulation efficiencies of phycocyanin-loaded and AEES-loaded zein fibers were 90.60% and 90.68%, respectively. Moreover, phycocyanin-loaded and AEES-loaded zein fibers were more active against Staphylococcus aureus than Escherichia coli. By measuring the total phenol content, flavonoid content, and antioxidant activity, the walnut samples were suitably packaged by both phycocyanin-loaded and AEES-loaded zein fibers. The packaging materials decreased peroxide and thiobarbituric acid values in the walnut samples. The results propose the suitability of zein fibers with phycocyanin and AEES for applications on perishable food products as promising antioxidant food packaging materials.

Structural elucidation of Gluten/Zein nanofibers prepared by electrospinning process: Focus on the effect of zein on properties of nanofibers

In this study, gluten/zein (G/Z) blends were electrospun with acetic acid as a solvent. The effects of zein content on the morphology, structure and properties of assembled gluten nanofibers were investigated. G/Z nanofibers were found to have diameters ranging from 209 nm to 462 nm, with smooth surfaces for ratios of 100:0 and rough surfaces for ratios of 30:70. The water contact angle (WCA) > 90 showed that mixed fibers were hydrophobic. SDS-PAGE showed that both proteins were present and were evenly distributed in G/Z nanofibers. The number of high molecular weight molecules decreased and the amount of low molecular weight molecules increased as the zein to gluten ratios increased. Nanofibers with α -helix structures were confirmed by FTIR, XRD, and CD analyses. The α-helix structure increased with increasing zein to gluten ratio in nanofibers, which also increased the characteristic of crystallinity and hydrophobicity. The characteristics of a miscible blend were confirmed by the single glass transition temperature (Tg) seen in the DSC thermograms of the G/Z nanofibers. With a decrease in the amount of zein in the nanofibers, the Tg dropped from 177.7 to 162 °C indicating that the mixed fibers were more flexible compared to the pure zein fiber.

Emulsion electrospinning of zein nanofibers with carotenoid microemulsion: Optimization, characterization and fortification

In this study, carotenoid microemulsion was encapsulated in zein nanofibers via emulsion electrospinning. Optimization study was applied to determine optimum parameters by response surface methodology. The voltage, flow rate and distance as optimum conditions were determined as 23 kV, 1.7 mL/h and 12.75 cm, respectively. Lycopene, β-carotene, encapsulation efficiency, encapsulation yield and zeta potential of zein nanofibers in optimum conditions were estimated as 4.054 mg/kg, 0.649 mg/kg, 77.78%, 41.76% and −29.73 mV, respectively. The addition of microemulsion affected nanofibers diameter and morphologies. Diffusion coefficient of zein nanofibers decreased with addition of microemulsion under optimum conditions. The electrospinning improved thermal stability of microemulsion. The carotenoid microemulsion could be entrapped into the zein fibers according to ATR–FTIR spectrum. Model foods were fortificated with zein nanofibers. The addition of nanofibers changed color of the foods during the storage. Carotenoid compounds were more stable in nanofibers followed by olive oil, milk and water.

Encapsulation of quercetin into zein-ethyl cellulose coaxial nanofibers: Preparation, characterization and its anticancer activity

In order to efficiently improve the colon-targeted delivery of quercetin, the hydrophobic core-shell nanofibers were fabricated to encapsulate quercetin using ethyl cellulose as the shell and zein as the core by coaxial electrospinning. The encapsulation efficiency of coaxial nanofibers reached >97 %. FTIR and XRD results revealed the interactions between quercetin and wall materials and quercetin was encapsulated in an amorphous state. The thermal stability and surface hydrophobicity of coaxial nanofibers were improved compared to the uniaxial zein fibers. After in vitro gastrointestinal digestion, the quercetin release from core-shell nanofibers was <12.38 %, while the corresponding value for zein fibers was 36.24 %. DPPH and FRAP assays showed that there was no significant difference in the antioxidant activity of quercetin before and after encapsulation. Furthermore, the encapsulated quercetin exhibited similar anti-proliferative activity against HCT-116 cells compared to the free form. The results suggest these coaxial nanofibers have potential applications in functional foods.

Antimicrobial active packaging for meat using thyme essential oil (Thymus vulgaris) encapsulated on zein ultrafine fibers membranes

The search for food products with fewer synthetic preservatives has grown, and industries are looking for strategies to extend the food shelf life safely. Essential oils are an alternative to control microbial growth in foods. This study aimed to evaluate the antimicrobial activity of thyme (Thymus vulgaris) essential oil encapsulated into zein fibers for application in meat trays as active packaging. The fibers were produced by electrospinning and evaluated by morphology, size distribution, contact angle, absorption profile in FT-IR spectra, and antioxidant and antimicrobial activities. The fibers presented uniform and continuous morphology, with a diameter variation between 468 and 830 nm. The fibers showed hydrophobic capacity, with water contact angle ranging from 134 to 150°, and high antioxidant capacity (98% of inhibition by the ABTS method). The membranes with thyme essential oil inhibited the growth of thermotolerant coliforms (45 °C), Escherichia coli, and coagulase-positive Staphylococcus in meat on trays under refrigeration (temperature of 4.5 °C). Therefore, the fibers membranes showed promising characteristics for developing active packaging for meat products.

Spiral grass inspired eco-friendly zein fibrous membrane for multi-efficient air purification

Air pollution, one of the severest threats to public health, may lead to cardiovascular and respiratory illnesses. In order to cope with the deteriorating air pollutant, there is an increasing demand for filters with high purification efficiency, but it's tough to strike a balance between efficiency and resistance. Fabricating an eco-friendly fibrous filter which can capture both PM2.5 and gaseous chemical hazards with high efficiency but under ultra-low resistance is a long-term challenge. Herein, inspired by the interesting ribbon shape of spiral grass, a green and robust 3D nonwoven membrane with controllable hierarchical structure made of self-curved zein nanofibers modified by zeolitic imidazolate framework-8 (ZIF-8) via bi-solvent electrospinning and fumigation welding method was fabricated. The obtained ZIF-8 modified zein membranes showed extraordinary overall performance with high PM2.5 removal efficiency (99.04 %) at a low stress drop (54.87 Pa), first-rate formaldehyde removal efficiency (98.8 %) and excellent photocatalytic antibacterial. In addition, the relatively weak mechanical properties of zein fibrous membranes have been improved via solvent fumigation welding of the joint zein fibers. This study provides a green and convenient insight to the manufacturing of environmentally-friendly zein fibrous membranes with high filtration efficiency, low air resistance and high formaldehyde removal for sustainable air remediation.

Facile construction of electrospun zein nanofiber loaded with Rana chensinensis skin collagen for wound care after caesarean section surgery

Numerous types of biomedical applications have found success using electrospun nanofibers. However, electrospinning techniques overlook Zein fibers favoring monolithic and coaxial fibers. Uniaxial electrospinning was used to construct Zein-structured nanofibers for wound healing, with the phase separation of electrospun polycaprolactone (PCL)/polyvinyl alcohol (PVA) in solution, providing the basis for the investigation. Successful loading of silver nanoparticles (AgNPs) and Rana chensinensis skin collagen (RCSCs) into Zein nanofibers (NFs) improved their bioactivity and antibacterial activity as wound dressings. Zein nanofibers were investigated for their heat conductivity, wettability, and mechanical characteristics. The cytotoxic effects of fabricated nanofibers were examined by using L929 fibroblast cells. Ag@RCSCs-NFs also increased cell migration and proliferation, and the wound scratch model was significantly reduced in size using an in vitro scratch assay. The antibacterial studies showed that the Ag@RCSCs-NFs have a potent antibacterial effect against the tested microbial pathogens (Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus)). Finally, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PCL/PVP, RCSCs, and Ag@RCSCs against two different bacteria were determined. These results suggest that wound care using Zein nanofibers loaded with RCSCs and AgNPs during cesarean section surgery has great promise.

Antimicrobial Bilayer Film Based on Chitosan/Electrospun Zein Fiber Loaded with Jaboticaba Peel Extract for Food Packaging Applications.

This work focused on developing an active bilayer film based on natural extract. Thus, the jaboticaba peel extract (JPE) was produced and characterized and showed promising application as a natural additive in biopolymeric materials. The zein fiber and bilayer films were produced using a chitosan film (casting) and zein fiber (electrospinning), with and without JPE. All samples were evaluated according to thickness, solubility in water, water vapor permeability, and main diameter, and for these, zein fiber, chitosan/zein fiber, and chitosan/zein fiber + 3% JPE showed values of 0.19, 0.51, and 0.50 mm, 36.50, 12.96, and 27.38%, 4.48 × 10-9, 1.6 × 10-10, and 1.58 × 10-10 (g m-1 Pa-1 s-1), and 6.094, 4.685, and 3.620 μm, respectively. These results showed that the addition of a second layer improved the barrier properties of the material when compared to the monolayer zein fiber. The thermal stability analysis proved that the addition of JPE also improved this parameter and the interactions between the components of the zein fiber and bilayer films; additionally, the effective presence of JPE was shown through FTIR spectra. In the end, the active potential of the material was confirmed by antimicrobial analysis since the bilayer film with JPE showed inhibition halos against E. coli and S. aureus.

Capsaicin-incorporated zein electrospun nanofibers: Characterization and release behavior

Capsaicin is an active compound in hot chili pepper that possesses many beneficial biological properties. However, sensorial attributes and sensitivity to environmental and food processing conditions can affect their stability, which could be restricted by encapsulation. In this study, electrospun zein fibers loaded with different concentrations of capsaicin (0.1%–0.4%) were evaluated in terms of encapsulation efficiency, morphology, and antioxidant activity. Nano-sized fibers were obtained with an encapsulation efficiency of 45.73%–93.11%, exhibiting a smooth surface and cylindrical morphology. The capsaicin-loaded zein fibers showed antioxidant activity in the range of 60%–68%. An optimum concentration of 0.24% capsaicin was selected for zein nanofibers. The release from the zein nanostructure in the food simulants followed Fickian transport. The interactions of capsaicin with zein were characterized by frequency shifts of the complex spectra. Thermogravimetric and thermal stability tests showed that capsaicin loss decreased following encapsulation in the electrospun zein mat. The thermal stability of encapsulated capsaicin increased more than 50% at 90 °C in comparison with free capsaicin. The nanofibers showed higher antimicrobial activity against Staphylococcus aureus than Pseudomonas aeruginosa and then Escherichia coli. Overall, zein acted as a good wall material for the encapsulation of capsaicin via electrospinning, extending the applications of capsaicin in foods and therapeutics.

High Toughness Composite Films Produced From Zein and Bamboo Fibers Based on Incorporating Biochar: Effects of Alkali Treatment

High Toughness Composite Films Produced From Zein and Bamboo Fibers Based on Incorporating Biochar: Effects of Alkali Treatment

Preparation and Characterization of Zein Electrospun Fibers for Nano Encapsulation of Ajowan (Trachyspermum copticum L.) Essential Oil

In this study, Ajowan essential oil was encapsulated in electrospun zein fibers at different amounts of loading (0, 22, 44, and 88 mg/ml). The resulting electrospun zein fibers containing Ajowan essential oil were characterized by scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), differential Scanning Calorimetry (DSC), fourier transform infrared (FTIR). Antimicrobial properties of fibers against Staphylococcus aureus and Escherichia coli were also determined by the disc diffusion method. GC/MS analysis was employed to identify the constituents of the Ajowan essential oil. The diameters of electrospun zein fibers increased with increasing concentration of Ajowan essential oil. Physical status of Ajowan essential oil in electrospun zein fibers was determined by XRD. Thermal properties of loaded electrospun fibers were studied by DSC. FTIR approved the encapsulation of essential oil in electrospun zein fibers. The encapsulation efficiency of Ajowan essential oil in electrospun zein fibers was about 100%. Antimicrobial results showed that the Ajowan essential oil loaded electrospun fibers were effective against S. aureus and E. coli. This could be due to the major constituents of Ajowan essential oil. Ajowan essential oil was successfully encapsulated in electrospun fibers for the first time.

A biodegradable composite filter made from electrospun zein fibers underlaid on the cellulose paper towel

Conventional petroleum-based synthetic polymeric fiber filter materials for separation may cause secondary pollution to the environment due to their non-degradable properties. Herein, we report a facile method of preparation of a biodegradable composite filter that can achieve filtration for air by underlaying the commercialized cellulose paper towel under electrospun zein fibers. The morphology of zein fibers was successfully steered via varying the weight ratios of ethanol/deionized water mixture solvent, as a result, the round or flat ribbon fibers were obtained. The effect of zein fiber morphology on air filtration performance was investigated both experimentally and theoretically. It was found that the flat ribbon fiber filter had a higher filtration efficiency (99%) for PM0.3 removal and a lower pressure drop (109 Pa) compared with the round zein fiber filter. Notably, the as-prepared composite filter can be biodegradable easily, contributing to green ecological environment. This work shows an efficient way to develop biodegradable filtration materials with the cheap price, easy availability of component materials, exhibiting a great potential application in air filtration area.

Characterization of ultrafine zein fibers incorporated with broccoli, kale, and cauliflower extracts by electrospinning.

Broccoli, kale, and cauliflower contain phenolic compounds and glucosinolates, which have several biological effects on the body. However, because they are thermolabile, many of these substances are lost in the cooking process. Electrospinning encapsulation, using zein as a preservative wall material, can expand the applications of the compounds in the food and pharmaceutical industries. The objective of this research was to characterize broccoli, kale, and cauliflower extracts and encapsulate them with the electrospinning technique using zein. Broccoli, kale, and cauliflower extracts contain five phenolic compounds and three glucosinolates. Fibers from broccoli, kale, and cauliflower showed high encapsulation efficiency, good thermal stability, and nanometric size, especially those containing extract and zein in proportions of up to 35:65. Fibers from broccoli, kale, and cauliflower containing extract and zein in proportions of up to 35:65 have the potential for effective nutraceutical application for the control of non-communicable chronic diseases or application in food packaging. © 2022 Society of Chemical Industry.

Encapsulation of thyme essential oil using electrospun zein fiber for strawberry preservation

BackgroundStrawberry is a nutrient-rich and important small fruit because of its high content of beneficial phytochemicals and several vitamins like vitamin C, vitamin E and vitamin B6. However, strawberry is highly perishable due to its susceptibility to mechanical damage, microbiological decay, and softening in texture. Recently, there has been an increasing interest in using various essential oils as natural food preservatives. Although, they have limited stability to exposure to high temperatures, light and oxygen, which could eventually affect sensory quality attributes. The electrospinning method is a simple and well-organized process that has been used to encapsulate essential oils. In this study, the effect of thyme essential oil (TEO) encapsulated into zein electrospun fiber film was assessed on extending the shelf life and preserving the quality of strawberry fruit during storage.FindingsResults indicated that TEO presented potent antibacterial activity against Bacillus cereus, Escherichia coli and Aspergillus fumigatus. The scanning electron microscopy images of zein fiber had a linear shape, absence of beads, and smooth surface. The encapsulation efficiency (EE) of TEO in the zein fiber was about 75.23%. Encapsulated TEO released at a slower rate than free TEO. The zein/TEO fibers (zein fiber film loaded with TEO) significantly (p ˂ 0.05) decreased weight loss and maintained the anthocyanin content, firmness and color of the strawberries during storage. After 15 days of storage, weight loss reduced about 15% and firmness was higher about 20% in packed fruit with zein/TEO fibers compared to control.ConclusionsInterestingly, after 15 days of cold storage, the strawberries firmness, appearance, and sensory evaluation, which are important quality factors from both postharvest and consumers’ viewpoint, in zein/TEO fiber treatment were acceptable and had higher scores compared to the control. In conclusion, the present study demonstrated the benefits of incorporating TEO into zein films, which could play a significant role in the active packaging and preservation of strawberry fruits.Graphical

Zein adsorbents with micro/nanofibrous membrane structure for removal of oils, organic dyes, and heavy metal ions in aqueous solution

Developing multi-functional media for effectively removing different contaminants coexisted in wastewater system is highly desired. Herein, zein, a natural protein possessing abundant functional groups in molecule, is chosen to be fabricated into micro/nanofibrous membranes as adsorbents and separation media. Zein fibers with novel groove ribbon structures, which possess better structural characteristics, are designed for obtaining good adsorption performance. The adsorption performances of zein fiber membranes are evaluated. The results show that zein fiber membranes have the adsorption capacities up to 94 g/g for motor oil, 168 mg/g for Congo red, and 189 mg/g for Pb2+ ion for 1000 mg/L initial solution concentration, showing considerable competitiveness as compared with the reported adsorbents. The zein membrane with groove ribbon fiber morphology exhibits optimal adsorption capability and can be attractive multi-functional separation media.

Antibacterial Properties of Coaxial Spinning Membrane of Methyl ferulate/zein and Its Preservation Effect on Sea Bass.

Methyl ferulate is a new natural antibacterial agent with strong activity and low toxicity. It has good application prospects in food preservation. In this paper, the antibacterial activity of methyl ferulate against Shigella putrefaciens was verified, and it was embedded into zein by electrospinning technology to prepare fiber membranes. The addition of methyl ferulate could improve the tensile strength of zein fiber membrane and decrease the crystallinity of the membrane, which was mainly a physical combination. The fiber membrane improved the thermal stability of methyl ferulate. The water contact angle (WCA) decreased to 54.85°. The results showed that methyl ferulate in fiber membrane could be released slowly, gradually exerting its antibacterial activity. After coating perch with methyl ferulate/zein fiber membrane, the growth of microorganisms in perch meat was inhibited, and the pH value and total volatile basic nitrogen (TVB-N)content were effectively increased. In a word, methyl ferulate had antibacterial activity in the fiber film, which was able to achieve a sustained release effect in the process of fish packaging, prolonging its antibacterial activity, and having preservation effect on sea bass; thus, it could be used in food packaging.