Speaker： Prof.  Qingrong Huang（Department of Food Science, Rutgers University, USA）
Title： Structure, Self-Assembly and New Applications of Corn Protein Zein
Time: 2:30 pm, Jul 01, 2013
Location:State Key Laboratory of Pulppaper Engineering,ROOM 306

Abstract:
Zein is a corn prolamin which has broad industrial applications because of its unique structure and physical properties. Currently, the high cost of extraction and purification, which is directly related to the dispersion of zein in different solvents, is the major bottleneck of the zein industry. In addition, the physical nature of zein in different solvents remains unclear. In this study, small-angle X-ray scattering (SAXS), static light scattering (SLS) and rheology were combined to study the structure and protein-solvent interaction of alpha-zein in both acetic acid and aqueous ethanol solutions. We found that the like-dissolve-like rule, the partial unfolding and the protonation of zein are all critical to understand the solution behaviors. Zein holds an elongated conformation (i.e., prolate ellipsoid) in all solutions as revealed from SAXS data. There is an “aging effect” for zein in aqueous ethanol solutions, as evidenced by the transition of Newtonian rheological profiles for fresh zein solutions to the non-Newtonian shear thinning behavior for zein solutions after storage at room temperature for 24 h. Such shear thinning behavior becomes more pronounced for zein solutions at higher concentrations. The SLS results clearly show that acetic acid is a better solvent to dissolve zein than aqueous ethanol solution, as supported by a more negative second virial coefficient. In terms of new applications, the use of zein in the fabrication of edible films, food packaging materials, highly-aligned nutraceutical-loaded zein fibers, and “sensor-on-packaging” device etc. will also be discussed