Thermodynamic and physiochemical insights into chickpea protein-Persian gum interactions and environmental effects

In the present work, the interactions between chickpea protein isolate (10 g·L^-1) and soluble fraction of Persian gum with various concentrations (from 0 to 14 g·L^-1) at different pH (3, 5, and 7) was characterized using turbidity, zeta-potential, differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and isothermal titration calorimetry (ITC). The turbidity was significantly measured bigger at pH 3 than others followed by pH 7 and the minimum value of turbidity was obtained for pH 5. Regardless of the pH, the maximum turbidity was measured at the SFPG/CPI ratio 1. Zeta-potential results showed a good perspective about making coacervates at pH 3 and soluble complexes at pH 7 and even pH 5. DSC results depicted that denaturation temperature of CPI was bigger with the presence of SFPG than CPI alone. Evaluation of the shifting and changing the intensity of peaks obtained by FTIR proved making the interactions between functional groups of biopolymers. The ITC results showed the electrostatic and hydrophobic interactions were responsible for making complexes and coacervates at pH 3 in the event that the hydrophobic interactions caused to binding the biopolymers together.