Understanding the kinetics and mechanism of heat-induced aggregation of chickpea globulin

The thermally induced aggregation kinetics and mechanisms of the most abundant chickpea globulin (CGb) were comprehensively evaluated. The thermal reaction order of CGb at 70 °C increased with rising salt concentration, whereas at 80 °C and 90 °C, the reaction order decreased as salt ion concentration increased, exhibiting complex multistep reaction behavior. The lowest aggregation rate was observed at 20 mM salt concentration regardless of temperature. The primary intermolecular forces within CGb thermal aggregates are hydrogen bonds and disulfide bonds, while prolonged thermal treatment enhances intermolecular hydrophobic interactions. Raman spectroscopy revealed that prolonged heating reduced the α-helix content in the amide I and amide III bands. Small-angle X-ray scattering results indicate that CGb thermal aggregates are multi-domain particles with loosely packed structures. The mean square radius of gyration and interparticle distance decrease due to the electrostatic shielding of salt ions. However, a significant amount of folded conformation persists within the aggregates.