The formation and characterization of nanostructured polyfunctional layers (films) based on protein adsorption at different fluid interfaces, such as air/water or oil/water interfaces, in the absence or in the presence of stearic acid are investigated. For instance, kinetics and thermodynamics of protein adsorption at the air/aqueous solutions were studied, thereby evidencing the protein surface active properties. The investigated protein was a globulin extracted and purified from aleurone cells of barley. The conjugated effect of protein and stearic acid simultaneous adsorption was also investigated, at the benzene/aqueous solutions interface. A stable mixed lipid and protein film has been formed by the co-adsorption of these biomolecules at liquid-liquid interface showing that the interaction between stearic acid and the protein is significant.