Electrospinning/Electrospraying of Protein Isolate and Alginate Solutions

Electrospinning and electrospraying involve the use of electrostatic field to spin or spray polymer solutions into fiber and particles, respectively. These processes have attracted considerable research interest due to their ability to produce ultrafine fibers and particles that are promising for micro/nano encapsulation and other applications. Our laboratory has been studying the electrospinning of a number of biopolymers for several years now, including soy protein isolate (SPI), whey protein isolate (WPI), and sodium alginate. Although these polymers form homogeneous solutions in water, the resulting solutions cannot be electrospun nor electrosprayed unless an organic solvent is used or a spinning aid, such as poly(ethylene oxide) (PEO) is added. In this seminar, the effects of PEO on electrospinning of these polymers, under different pH and concentration conditions, will be discussed. Changes in protein secondary structure and polymer solution properties (viscosity, conductivity and dynamic surface tension), as induced by changes in pH, will be discussed. The nature of PEO-biopolymer interaction is elucidated using NMR and FTIR data. Based on the electron microscopy and spectral information on hand, it is likely that the positive effects of PEO during electrospinning and electrospraying are mainly attributable to physical entanglement and/or entrapment of the biopolymer by the PEO scaffolds. Finally, potential applications of electrospun soy/whey protein and alginate fibers for food and packaging applications will be presented.