Function of pea protein isolate enhanced by ferulic acid via complex/conjugate formation.

This study exploited ferulic acid (FA) to enhance the function of pea protein isolate (PPI) via PPI-FA complex/conjugate formation: non-covalent complex (NPF), free radical-induced grafting conjugate (FPF), and alkaline-mediated conjugate (APF). The influences of these different modifications with FA concentrations on the structure and properties of the complexes/conjugates were systematically investigated. FPF and APF performed higher reactivity and binding capacity to FA. NPF formation relied on hydrogen bonds and hydrophobic interactions, while FPF and APF were stabilized mainly by CN and CS bonds, increasing the exposure of tyrosine and tryptophan residues in PPI. FT-IR, SEM and AFM also revealed multiscale structural changes of PPI with FA, as well as the particle size, zeta potential, and surface hydrophobicity of PPI-FA complex/conjugate fluctuated with modification methods. Among them, APF exhibited superior thermal stability, antioxidant property, and emulsifying activity, providing a novel strategy for the application of PPI and FA in food industry.