Mechanical and spectroscopic characterization of crosslinked zein films cast from solutions of acetic acid leading to a new mechanism for the crosslinking of oleic acid plasticized zein films.

This study discovered through FTIR, FT-Raman and rheological measurements that glutaraldehyde binds to zein through the amine groups of glutamine turns by replacing the already-bonded oleic acid molecules and forming imine structures. As a secondary crosslinking mechanism, glutaraldehyde unfolds some of the α-helices and turns them into β-sheets. While crosslinking resulted in stiffer and less ductile zein films, it made the surface of the films rougher, measured using AFM, and more hydrophilic, measured using WCA.