Fabrication of food-grade nanofibers of whey protein Isolate–Guar gum using the electrospinning method

Abstract

In this study, food-grade whey protein isolate (WPI) nanofibers were fabricated in combination with guar gum (GG) using the electrospinning method for the first time. The mixture solution of WPI and GG in acidic condition showed spinnability in the concentration range of (WPI: 7–12 and GG: 0.7–0.9 % wt) at 20 kV voltage, 8 cm capillary collector distance and 0.6 ml/min flow rate. The visible transformation in the morphological appearance from nanofibers containing beads to beads free nanofibers was seen when the GG concentration increased from 0.8 to 0.9 % wt at a fixed concentration of WPI (7% wt). Based on the scanning electron microscopy (SEM) images the ultrathin-bead free nanofibers with diameters of 466 ± 87 nm were prepared using WPI and GG at concentrations of 9 and 0.7 % wt (pH = 3.5), respectively. The electrospinning efficiency of the WPI-GG solution was strongly influenced by its concentration ratio and by changes in the viscosity of GG solution in the presence of WPI. Fourier-transform infrared spectroscopy (FTIR) of GG-WPI blended nanofibers showed the formation of the α-helical structure of WPI instead of the intramolecular β-sheet structure of pure WPI. The thermal stability of the electrospun polymers revealed that the stability of GG and WPI fibers improved at a higher temperature range in comparison to native WPI and GG.