Complexation between soy peptides and epigallocatechin-3-gallate (EGCG): Formation mechanism and morphological characterization

This study investigated the feasibility of using epigallocatechin-3-gallate (EGCG) as a carrier to interact with and precipitate peptides from soy protein hydrolysate water. EGCG was added to soy peptides, resulting in the formation of aggregates that precipitated upon centrifugation. The recovery efficiencies of peptides were evaluated at both an acidic pH of 4.5 and a neutral pH of 7.0 with varying concentrations of EGCG. Results showed that the peptide recovery increased with increasing concentrations of EGCG. The maximum recovery of peptides was 57.17%, at pH 4.5 and an EGCG/peptide ratio of 0.40. Further increases in EGCG concentrations did not result in any changes to peptide recovery, suggesting that the interaction between EGCG and peptide followed a Poisoned Growth Model. The peptides recovered by EGCG have much better solubility than acid precipitated peptides. This work establishes the feasibility of, and methodology for, recovering peptides from water solution using EGCG as an efficient carrier.