Electrospinning Pullulan Fibers from Salt Solutions.

Area of Science:

• Food Science
• Materials Science
• Polymer Chemistry

Background:

• Growing interest in electrospinning biopolymers for food applications.
• Pullulan (PUL) is explored as a carrier to enhance electrospinnability of natural polymers.
• Understanding salt's effect on PUL electrospinning is key for food-grade fiber production.

Purpose of the Study:

• To investigate the impact of NaCl and Na₃C₆H₅O₇ on pullulan (PUL) electrospinning.
• To determine optimal salt concentrations for producing ultrafine, bead-free PUL fibers.
• To analyze how salt addition affects solution and fiber properties for food-grade applications.

Main Methods:

• Electrospinning of PUL solutions with varying NaCl and Na₃C₆H₅O₇ concentrations.
• Fourier-transform infrared (FTIR) spectroscopy to analyze salt-PUL interactions.
• Scanning electron microscopy (SEM) to characterize fiber morphology and diameter.

Main Results:

• Salt addition altered solution properties (viscosity, conductivity, surface tension) and fiber characteristics (size, melting point).
• Bead-free PUL fibers were achieved with 8% PUL and 0.20 M NaCl (124 nm) or 0.05 M Na₃C₆H₅O₇ (154 nm).
• Higher salt concentrations led to flattened fibers with defects and excess salt on the surface.

Conclusions:

• Salt concentration critically influences the electrospinning of PUL for food-grade applications.
• Specific salt concentrations enable the production of uniform, ultrafine PUL fibers.
• Findings provide valuable data for developing electrospun biopolymers in food processing environments.