Properties of Poly (ethylene oxide)/ whey Protein Isolate Nanofibers Prepared by Electrospinning

A mixture of solutions of whey protein isolate (WPI) and poly (ethylene oxide) (PEO) were employed to fabricate nanofibers by the electrospinning technique. The PEO/WPI ratio was varied in order to obtain PEO:WPI nanofibers with different concentrations of homopolymers. The dependence of morphology, viscosity, conductivity, surface tension, thermal and vibrational properties was studied as function of the PEO/WPI ratio. The results show that at higher viscosity, we obtained soft and smooth fibers with diameters ranging between 227 ± 36 nm and 264 ± 66 nm; while the solutions with low viscosity (<0.415 Pa · s), low surface tension (<55 mN/m) and high conductivity (>527 μScm−1) promote the formation of beads. The nanofibers were thermally stable for temperatures below 200 °C and the initial thermal degradation temperatures is slightly affected by the PEO:WPI ratio. The FTIR results revealed that the crosslinking favors the formation of fibers. Rosmarinus officialis extract was used for explore a possible application of the nanofibers as a delivery system. The dissolution rate of the rosemary extract from the nanofibers was measured in phosphate buffer solutions with pH of 1.2, 7.5 and 9.0. The total rosemary content was dissolved from the nanofibers, in the aqueous medium, on a time with depends on the pH of the buffer solution.