This article discusses the role of electrospun nanofibers in beverage filtration applications in detail, along with fabrication methods and relevant research examples.
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Defining Electrospun Nanofibers
Electrospinning is a simple process to manufacture nanoscale polymer fibers without high temperature or pressure. The polymer solution or melt is converted into nanofibres under high tension.
In a conventional electrospinning machine, a solution or melt is placed in a syringe. The negative terminal is connected to the receiving device and the positive to the spinning solution. The external electric field is applied to the droplet at the nozzle opposite to the surface tension direction. A gradual increase in the electric field overcomes the surface tension, and the droplet first changes its shape into a conical shape known as the “Taylor cone”, and then, with the increase in electric strength to a critical value, the Taylor cone has a radius . This beam is deposited on the collecting plate and forms electrospun nanofibers.
Beverage Industry Applications
One of the most common methods of removing suspensions and other components that can alter the quality of a beverage is filtration. The use of electrospinning to make nanofiber films with high porosity, small diameter coupled pores and large surface area has generated considerable interest within the beverage filter industry.
Electrospun nanofiber films are now being tested in the beverage sector, especially in the production of fruit juice and beer. As discussed below, there are several ways to apply electrospun nanofibers for beverage filtration.
Polyethylene Terephthalate Nanofiber Membrane (PET ENM)
Initial research has explored the use of a polyethylene terephthalate nanofiber membrane (PET ENM) for filtering apple juice, showing promising results. The juice flow of PET ENM was twenty times greater than the juice flow of the ultrafiltration membrane and the operating pressure was seventy times lower than the pressure of the ultrafiltration membrane. Apart from that, the physicochemical parameters of both juices produced by PET ENM filtration-ultrafiltration were identical and met the required standards.
Electrospun Nylon-6 Nanofiber Membranes (NFM)
Ideally, the juice’s antioxidant properties should be preserved. At the same time, the ability to remove phenols during juice processing is enhanced to preserve the nutritional value of juice while improving shelf life and stability.
Antioxidant properties of apple juice are not affected by nanofiber membranes such as electrospun nylon-6 nanofiber membranes (NFM) as filter media. The filtering capacity of NFM absorption membranes for oxygen radical is comparable to that of commercial polyamide membrane filters.
Membrane filtration is essential for removing microorganisms from beverages. Researchers tested electrospun NFM membranes for their ability to remove yeast cells and bacteria from beer, and isothermal calorimetry confirmed their efficacy.
Addition of enzymes
Adding enzymes to the surface of the fiber membrane is a typical way to improve filter performance. Enzyme immobilization can be achieved through the electrospun nanofiber film. It is possible to increase the amount of enzyme that can be immobilized per unit mass by using electrospun nanofiber films that have a high specific surface area.
Layer by layer self-assembly
Layer by layer self-assembly coats the negatively charged nanofiber films with both positively and negatively charged naringinase (NA) and alginate (ALG). Naringine and limonine are effectively removed from grapefruit juice using (NA/ALG)10.5-CA’s adsorption and hydrolysis processes, increasing the juice’s sensory properties and economic value.
Electrospun nanofibers have been used for various applications both in the past and in recent years. For example, electrospun conductive polymer (CP) ultrafine nanofibers are used in electromagnetic interference shielding, energy storage by nanomaterials, flexible electronic devices, controlled drug delivery by nanotubes, tissue regeneration, neural electrodes, artificial muscles and biochemical nanosensors. However, the use of electrospun nanofibers in beverage filtration is very recent and little research has been done in this area.
A recent study, conducted in 2021 by Indian scientists, discusses the potential applications of nanofibers in the beverage industry. This study investigates the use of electrospun nanofibers for CO . capture2 pollutants and recycle them back for cost-effective carbonation of beverages.
Nanopores of these nanofibers provide effective capture of hydrocarbons from the airflow. This study also discusses various applications of nanofibers in the beverage industry such as pesticide detection, monitoring storage conditions, nanosensors for quality assessment, encapsulation matrices for protecting aromatic and volatile compounds in the beverages, and beverage packaging materials and filtration of beverages.
Nanotechnology evolves with each passing day. It has already adopted conventional technology in various industrial processes. In the beverage filtration industry, the recent introduction of electrospun nanofibers is expected to be revolutionary due to their cost effectiveness and high efficiency.
The nanofiber films produced by electrospinning have a high porosity and a large surface area, which can be adapted to a specific target. This flexibility, along with cost efficiency, makes electrospun nanofibers ideal for beverage filtration.
References and further reading
Huang, H., Song, Y., Zhang, Y., Li, Y., Li, J., Lu, X., & Wang, C. (2022). Electrospun nanofibers: current progress and applications in food systems. Journal of Agricultural and Food Chemistry, 70(5), 1391-1409. https://doi.org/10.1021/acs.jafc.1c05352
Leena, MM, Bharathi, SV, Moses, JA, & Anandharamakrishnan, C. (2020). Potential applications of nanofibers in the beverage industry. In Nanoengineering in the Beverage Industry (pp. 333-368). Academic press. https://doi.org/10.1016/B978-0-12-816677-2.00011-9
Salehi, F. (2014). Current and future applications of nanofiltration technology in food processing. Food and Bioproduct Processing, 92 (2), 161-177. https://doi.org/10.1016/j.fbp.2013.09.005
Wang, XX, Yu, GF, Zhang, J., Yu, M., Ramakrishna, S., & Long, YZ (2021). Conductive polymer ultrafine fibers via electrospinning: preparation, physical properties and applications. Advances in Materials Science, 115, 100704. https://doi.org/10.1016/j.pmatsci.2020.100704
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