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theses

Electrospinning has been used to produce nonwoven mats from the nano- and microscale fibers by applying an electric field to a viscous polymer solution. Milk-based proteins (nonfat dry milk and caseinates) cannot be electrospun, they must incorporate with an electrospinnable, food- grade carrier polymer to produce edible fibers. To obtain the fibers, polymer solutions must meet some criteria specifically viscosity and molecular chain entanglement, which is a necessity for a successful electrospinning process. However, many proteins, which can self-assemble in 3-D structure by intermolecular interactions including hydrogen bonds, hydrophobic, and electrostatic interactions, have lack of chain entanglements that can be improved by their dissolution in organic polar solvents which is not for food use.
This study demonstrates the electrospinning of nonfat dry milk (NFDM) and caseinate proteins (CAS) blended with an electrospinnable polysaccharide, pullulan (PUL) to produce food-grade ultrafine fibers and fibrous mats. It also evaluates the theoretical mechanism behind the inability to electrospin these milk-based proteins by investigating the relationship between solution rheology and fiber formation and morphology. First, neat NFDM, CAS, and PUL have to fully dissolve in aqueous solutions and governing parameters need to be optimized. Based on these optimized conditions, NFDM and CAS can be electrospun into the ultrafine fibers and fibrous mats as they blended with PUL.
The chemical and physical properties of NFDM and CAS blended with PUL fibers were examined using SEM micrograph, FTIR-ATR spectra, and the mechanical properties of their fibrous mats. Furthermore, bioactive living cell, Lactobacillus Rhamnosus GG, was chosen as a model application to encapsulate within the electrospun CAS: PUL blend fibrous mats to evaluate its recovery.
This study establishes the fundamental principles for the NFDM- and CAS-based nanofibers and nanofibrous mats for future studies. The nanofibrous mats possess smaller diameter fibers increasing the surface area-to-volume ratio and the porosity between the fibers. Therefore, the motivation of this study is to use these food-grade fibrous mats in many food applications including controlled nutrient delivery or flavor enhancement, sensitive bioactives encapsulation, texture improvement, functional foods, and beverages contribute to health-promoting foods.

ETD_9299

doi:10.7282/T3NZ8C98

Ph.D.

Includes bibliographical references

by Serife Akkurt

ETD doctoral

The author owns the copyright to this work.