In this study, pea protein isolate (PPI) and γ-polyglutamic acid (γ -PGA) were used to form a soluble complex through electrostatic interaction to improve the stability of pea protein in an acidic environment. Turbidity, Zeta potential, phase diagram and microstructure were used to study the factors affecting the formation of the soluble complex (pH, mixing ratio r, protein concentration), and to determine the conditions for the formation of the complex. The protein solubility, surface hydrophobicity, emulsifying activity, and emulsifying stability were measured under this condition. The results showed that the formation of the complex increased the electrostatic repulsion of the system, and improved the stability of PPI in an acidic environment. At pH 4.5 and high protein concentration (10.0 g/L), a soluble complex was formed in the r=1 and r=2 systems, and the protein solubility and surface hydrophobicity were significantly increased (P<0.05). When r=1, the emulsifying activity and stability of the system were the best.
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