Thesis Type: Postgraduate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Food Engineering, Turkey
Approval Date: 2018
Student: SEREN OĞUZ
Co-Supervisor: SERPİL ŞAHİN, SERVET GÜLÜM ŞÜMNÜAbstract:
Electrospinning is a process that produces continuous nanofibers through the action of an electric field imposed on a polymer solution. In this thesis, it was aimed to produce pea flour and hydroxypropyl methylcellulose (HPMC) based homogenous nanofibers by electrospinning. The effects of pH, pea flour and HPMC concentration, and microfluidization on apparent viscosity, electrical conductivity of solutions and nanofiber characteristics were studied. In addition, the effects of voltage and flow rate were analyzed. Solutions were prepared at different pH values (7, 10, 12), with different pea flour concentrations (1%, 2% (w/v)) and HPMC concentrations (0.25%, 0.5%, 1.0% (w/v)). For all pea flour concentrations, increase in pH cause a significantly rise in consistency coefficient (k). Increase in pea flour concentration also increased consistency coefficient for alkali conditions. Electrical conductivities were not affected by pH, pea flour and HPMC concentration significantly. It was possible to obtain homogenous fibers when solutions were prepared at basic pH. On the other hand, neutral solutions produced fibers with beads. The increase in pH, flour and HPMC concentration increased nanofiber diameter. Nanofibers obtained from solution containing 1% pea flour and 0.25% or 0.5% HPMC at pH value of 10 had the smallest diameter ranging from 177 to 179 nm. Microfluidization cause an increase in consistency coefficient and a deformation on the fiber morphology. Nanofibers were characterized by water vapor permeability (WVP) and color. Flour concentration increased WVP but did not affect color. The composition of solutions was suitable for electrospinning process which was confirmed by Fourier-transform infrared (FTIR) analysis.