Nanoencapsulation of vitamin E via electrospinning and the investigation of factors affecting electrospinning, characterization of nanofibers

In today`s world, nanoscience and nanotechnology researches and applications that are some of the most important studies has been developing rapidly. Due to using of new techniques and allowing the production of higher quality products, nanotechnology has caused a tremendous interest in research and commercial attention over the past decade. Nanotechnologies are estimated to impact at least $3 trillion across the global economy by 2020. Since nanotechnology is an interdisciplinary area, it enables lots of scientist to be together from different disciplines such as biology, chemistry, engineering and physics. This situation causes that nanotechnology industries worldwide may require at least 6 million workers to support them by the end of the decade. Nanotechnology includes the production and use of extremely small size of the materials and devices size ranging from 0.1 to 100 nm described as nanoplates, nanofibers and nanodots. Because it has a very large surface to volume ratio and surface activity due to their nanoscale size, it brings important features to the materials included. Development of materials containing nanoparticles have been investigated in many sectors in recent years and this provide great benefits to the industries like cosmetic, food and beverage, textile, pharmaceutical, electronics. Considering the technological applications in the food industry, it appears to have very potential applications in many aspects. Food processing, development of new functional products, transportation and controlled release of bioactive agents, detection of pathogens, extending the shelf life via developing new packaging products are some of the potential applications. In recent years, in order to improve the functional food products, scientists have been taking advantage of nanotechnology. In some studies, it is aimed to increase the effectiveness of the functionality of the products and distibution of these products to the required point in the body via implementation of nanotechnological methods. The Vitamin E is a vitamin that is added to food products to enrich the functionality of food. Since Vitamin E is a natural and sensitive antioxidant to some conditions like heat, enzyme etc., it tends to be corrupted. Because of this situation its bioavailability is limited with corruption and lower absorption during the release/distruption. In order to prevent the such problems, studies are conducted including nanoencapsulation of active materials like vitamin E. The encapsulation procedure is defined as capturing of a bioactive material into another and with this procedure production of particules from nanometers to milimeters make possible. In recent years, there is an increasing interest about downsizing-from micrometers to nanometers- due to the aim of minimizing the possible effect of encapsulated materials on the food structure and appearence. Downsizing the dimensions of the encapsulated materials has its own additional benefits on specific functional food practise. The encapsulation provides the protection of the stabilization of bioactive materials, imprisonment of volatile compound such as aroma, obtainment the resistance towards chemical reactions. Besides these, encapsulation of vitamin E into the polimeric nanoparticules has its adventages too. These adventages are preservation of bioactive component, enrichment of bioavailability and targeted delivery. There are several ways for encapsulation of food materials.In this study, a new production technique called electrospinning technique which is based on high electric field was used. This technique is used to make production of polymer/ biopolymer based nanofibers possible. Nanofibers are called as fibers with diameters from 1 to 100 nanometers. Several techniques were reported in early literature for the laboratory preparation of nanofibers. However, electrospinning is easier and more economical method comparing to other methods for obtaining nanomaterials and used in tissue engineering, biosensors, filtration, wound dressings, drug delivery, and enzyme immobilization. Electrospinning which renders electrostatic fiber formation utilizes electrical forces to produce polymer fibers with diameters ranging from 2 nm to several micrometers using polymer solutions of both natural and synthetic polymers. However, in food related studies, generally natural biopolymers are used. In our study, nanoencapsulation of vitamin E by producing nanofibers was carried out. Then, it was carried out that vitamin E-gelatin nanofibers producing by using gelatin that is natural and suitable to use in foods were characterized. In study, vitamin E, which is encapsulated in gelatin polymer and nanoscale nanofibers were produced with these conditions: 22 kV voltage, 0.5 ml / h flow rate, 10 cm plates distance from syringe. Electrical conductivity, surface tension, dielectric constant and rheological properties of gelatin and vitamin E-gelatin solutions which are prepared before electrospinning process were determined. Then, SEM images, contact angle, zeta potential, diffusion coefficient and particle size was measured, which is required for the characterization of nanofibers producing by electrospinning method. The measurement results were compared with the results obtained in the literature. According to SEM results, it was observed that production of nanofibers occured ranging from 45 nm to 300 nm. These results have shown we achieved decreasing the size of materials. The zeta potential values of nanofibers obtained at 22kV were - 1.16 ± 0.314 mV. Since this result is in the range between +25 and -25, these nanofıbers are not stable in ethanol. Because of this reason, we decided vitamin E- gelatin nanofibers are not stable in ethanol. If we would like to see the nanofibers are stable in ethanol, it should have been out of this ranges. Also, according to the studies conducted by Okutan et al. (2014) under 28 kV, 1 ml/s flow rate and 10 cm plate distance, the zeta potential of gelatin nanofibers are +12,40±0,00. Comparing this result with our results, it can be seen gelatin nanofibers are more stable than our results. After contact angle experiments, it was shown that vitamin E added hydrophilic character to gelatin nanofibers when comparing to the conducted studies. Also, when comparing with our diffusion constant value (0.223 ± 0.015 μm2 /s) with the experimental values (0,65 ± 0,04) under 28 kV, 1 ml/s flow rate and 10 cm plate distance conditions, conducted by Okutan et al., 2014, it can be seen that E vitamin has increased the difussion ability of gelatin nanofibers. The obtained results are fundamental to the studies to investigate controlled release of vitamin E in the future projects.