Influence of Salts on CMP Nanostructures

Abstract

Caseinomacropeptide (CMP) is a bioactive peptide obtained during the cheese-making. The aim of this work was to analyze the influence of salts (NaCl and CaCl2) in the formation of CMP nano-structures by Dynamic Light Scattering (DLS). Due to high electrostatic repulsion, at pH ≥ 6.5 CMP is found in the monomeric form. However, the presence of salts (NaCl, CaCl2) promoted CMP self-assembly to form dimers, tetramers, hexamers or more associated forms, depending on the type and concentration of salt. These associated forms self-assembled over time by electrostatic bond at pH < 4.5. The rate of CMP self-assembly was decreased or even was deleted with increasing salt concentration, maybe by an excessive neutralization of CMP charge. The presence of salts impacted on the first stage of CMP self-assembly of by the formation of tetramers linked by hydrophobic bonds.