Heteroprotein complex formation of soy protein isolate and lactoferrin: Thermodynamic formation mechanism and morphologic structure

Abstract Heteroprotein complex coacervate (HPCC) is one of the most promising electrostatically driven biopolymer materials. In this paper, the formation conditions, thermodynamic formation mechanism, and morphologic structure of soy protein isolate/lactoferrin (SPI/LF) complex coacervate were investigated. The SPI/LF complex coacervates prepared under optimal conditions were electrically neutral and followed the principle of charge compensation. Electrophoresis and isothermal titration calorimetry verified that all individual SPI fractions participated in HPCC and the stoichiometry of the SPI/LF complexes was the same as their optimal mixing ratio. Moreover, SPI/LF complex coacervation was thermodynamically favoured (ΔG   0) and negative enthalpy change (ΔH