Examining Committee
Dr. Massimo Marcone, Chair
Dr. Dr. Iris Joye, Advisor
Dr. Loong-Tak Lim, Co-Advisor
Dr. Michael Rogers, Department Member

TITLE: Impact of deamidation on the physicochemical properties and air-water interfacial behaviour of gliadin nanoparticles

ABSTRACT: Deamidation effectively alters the physicochemical properties of gliadin through conversion of uncharged amino acids to negatively charged amino acids which led to a shift in the isoelectric point (IEP) of gliadin from ~pH 6.5 to ~pH 4.5-5.5 in deamidated gliadin. The shift in IEP of the proteins also alters the electrostatic interactions of particles made with (deamidated) gliadin (GNPs): introducing additional negative charges resulted in an improved overall stability of deamidated GNPs upon exposure to e.g., high temperatures, elevated ionic strength, and pH variations. GNPs proved to be promising for stabilization of foams. Their behaviour at the air-water interface, however, is substantially impacted by pH. Particles made with untreated and deamidated gliadin exhibited a greater tendency to adsorb and interact at the interface closer to their IEP. This study provides crucial insights into the potential of deamidation to tailor gliadin and GNP properties for specific food applications.