Development and characterization of food-grade electrospun fibers from amaranth protein and pullulan blends

In this work, novel ultrathin electrospun fibers from different blends of protein isolate (API) and the carbohydrate polymer pullulan, with or without the surfactant Tween 80, have been developed and characterized. The solution properties and molecular organization of the electrospun structures were studied and correlated with the morphology of the obtained fibers. The presence of pullulan in the blends resulted in increased viscosity and lower conductivity of the solutions, related to a better chain entanglement and decrease in the polyelectrolyte protein character, respectively, both factors needed for fiber formation. Infrared spectral changes indicated that defect-free fibers were correlated with extended et-helical protein structures, which for the blends with greater protein contents, were only obtained upon surfactant addition. The thermal stability of the hybrid fibers was better than that of pure API and slightly increased upon surfactant addition, while the water stability of the blends was highly dependent on fiber composition. These structures have a great potential for the encapsulation of bioactives for functional food applications. (C) 2013 Elsevier Ltd. All rights reserved.