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Volume 16, Issue 87 (5-2019)
Abstract
In the present study, Azivash leaf gum (Corchorus olitorius L.) was used for the first time with the help of an electroporation technique in the presence of poly-vinyl alcohol as a natural nanofibre. At first, the effect of different concentrations of Azivash gum aqueous solution (2, 2.5 and 3 g / l) with polyvinyl alcohol (P70: G30, P60: G40, P50: G50 and P0: G100) on viscosity and electrical conductivity as the main soluble parameters was studied. The results showed a significant increase in viscosity concentration with gum concentration and volume ratio of polyvinyl alcohol (p <0.01). Regardless of the concentration of Azivash gum, by increasing the ratio of gum to polyvinyl alcohol, the electrical conductivity increased significantly (p <0.05). In the study of shear stress-shear rate of Azivash gum and polyvinyl alcohol solutions, pseudoplastic behavior was confirmed. Investigating the fitting of rheological data with Herschel-Balkly models, power law and casson showed that the Herschel-Balkly model with the highest R2 / RMSE is desirable to describe the flow behavior. The values of the flow index and consistency coefficient were determined by the model. After the electrospining of azivash leaf gum-polyvinyl alcohol in a constant condition (voltages of 18 kV, volumetric flow rate of 0.7 ml/hr and needle distance to a collector plate of 12 cm), by microstructure analysis and based on the morphology of bead-free fibres, the Azivash gum formulation at 2 g / L concentration and the mixing ratio of 70:30 with polyvinyl alcohol was selected as the most suitable formulation with a mean nanofiber diameter of 90 nm. Based on FTIR resulrs, addition of gum to polyvinyl alcohol caused an increase in peak intensity due to carbonyl and hydroxyl groups glycosidic vibrations. Also, the thermal stability of the gum nanofibers of Azivash improved in the presence of polyvinyl alcohol.
Volume 17, Issue 99 (May 2020)
Abstract
Nanoencapsulation is one of the most important processes to improve the chemical stability of aromatic and volatile compounds, to prevent their undesirable interactions with food ingredients, and their intelligent release into the food industry. Encapsulation may be defined as the process to entrap one substance within another substance, thereby producing particles with diameters of a few nm to a few mm. Due to the sensitivity of the bioactive compounds, there are different encapsulation techniques. In recent years, electroencapsulation or encapsulation using electrohydrodynamic processes (electrospinning and elcrospraying) which is a simple and effective technique to preserve and increase bioavailibility of components, has attracted particular attention of food and drug scientists. Electrospray is very important as one of the liquid spraying methods due to the production of tiny droplets and uniform distribution. One of the advantages of the electrospray system is that it has high control over the particle size distribution, with the particles almost uniform. Electrospray capsules also have the potential to prevent the destruction of carotenoids and vitamins. In addition to the protective effects of encapsulation on nutrients, they can also be used to improve the fluidity, transport, and displacement properties of materials, since they are solid form rather than liquid. In fact, during the microencapsulation of nutrients, enzymes or other substances (such as volatile oils, taste and colorants, enzymes, etc.) in micro or nano size by wall materials that can form lipids, protein biopolymers and polysaccharides or their complex is surrounded and protected from external factors. This article briefly describes the properties of the electrospray method and its applications.