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. In the crosslinking conditions in this study, the number of crosslinks estimated from rubber elasticity theory were not enough to change the water vapor permeability of the films significantly. Improving the understanding of crosslinking mechanism and its effects on physical and chemical properties of zein films can be useful to develop stiffer, stronger and more durable platforms for biodegradable biosensors, microfluidic devices or scaffolds.

这项研究通过FTIR，FT-Raman和流变学测量发现，戊二醛通过取代已经键合的油酸分子并形成亚胺结构，通过谷氨酰胺匝的胺基团与玉米醇溶蛋白结合。作为第二交联机理，戊二醛使一些α-螺旋展开并将其变成β-折叠。尽管交联导致玉米蛋白膜更坚硬，延展性更低，但使用AFM测得的膜表面更粗糙，而使用WCA测得的膜更亲水。在本研究的交联条件下，根据橡胶弹性理论估算的交联数量不足以显着改变薄膜的水蒸气透过率。