Synthesis of tubular nanostructures from wheat bran albumins during proteolysis with V8 protease in the presence of calcium ions

• Wheat bran albumins were subjected to proteolysis with V8 in presence of calcium.
• At a defined mole ratio (protein/V8/calcium), long threads were formed as seen by SEM.
• The threads were hollow tubes, inner diameter 100 nm, so they qualify as nanotubes.

There are very few reports on the self-assembly of peptides derived from proteins of agro industrial byproducts origin. Although it has been claimed that purity is a determining factor in peptide self-assembly, whether proteins extracted using water along with other components also form self-assembled structures is not known. The results of this work prove that albumins from wheat bran, a byproduct obtained from the milling industry, can form tubular nanostructures during their hydrolysis with the V8 protease in the presence of Ca2+. Electron microscopy of the hydrolysate revealed that under specific conditions, long filaments are formed, which are nanotubes of several microns in length, with inner and outer diameters of 100 and 200 nm, respectively. The infrared analysis of the hydrolysate identified −OOC–Ca2+ interactions and changes in beta sheet content in response to variations in protein/V8/Ca2+ molar ratios. A model that explains the probable mechanism of the observed self-assembly is discussed.