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Zein is a corn prolamin that has broad industrial applicationsbecause of its unique physical properties. Currently, the high costof extraction and purification, which is directly related to the dispersionof zein in different solvents, is the major bottleneck of the zeinindustry. Solution behaviors of zein have been studied for a longtime. However, the physical nature of zein in different solvents remainsunclear. In this study, small-angle X-ray scattering (SAXS), staticlight scattering (SLS), and rheology were combined to study the structureand protein–solvent interaction of α-zein in both aceticacid and aqueous ethanol solutions. We found that the like-dissolve-likerule, the partial unfolding, and the protonation of zein are all criticalto understanding the solution behaviors. Zein holds an elongated conformation(i.e., prolate ellipsoid) in all solutions, as revealed from SAXSdata. There is an “aging effect” for zein in aqueousethanol solutions, as evidenced by the transition of Newtonian rheologicalprofiles for fresh zein solutions to the non-Newtonian shear thinningbehavior for zein solutions after storage at room temperature for24 h. Such shear thinning behavior becomes more pronounced for zeinsolutions at higher concentrations. The SLS results clearly show thatacetic acid is a better solvent to dissolve zein than aqueous ethanolsolution, as supported by a more negative second virial coefficient.This is majorly caused by the protonation of the protein, which wasfurther verified by the dissolution of zein in water (a nonsolventfor zein) with the addition of acids. [ABSTRACT FROM AUTHOR]