Regulation of peptide hydrophobicity by self-assembly of casein peptides with ferulic acid to potentially reduce peptide bitterness and improve in vitro digestive activity

The main purpose of this study was to investigate the structural properties, mechanism of action, bitter taste changes, and γ-aminobutyric acid transaminase (GABA-T) inhibitory activity of CH-FA complexes in vitro digestion by self-assembly of casein hydrolysate (CH) and ferulic acid (FA). Structural analysis revealed that CH-FA was formed spontaneously, driven primarily by hydrophobic interactions and hydrogen bonding. The electron tongue results demonstrated that the bitter value of CH was reduced by 30.89 %, which may be due to the improvement of the hydrophobic amino acid microenvironment and the reduction of binding to the bitter receptor, thereby reducing the bitterness. In vitro digestion stage, the protein digestibility of CH was inhibited by FA, which increased the GABA-T inhibitory activity of CH by 13.96 % at the end of digestion. The present study elucidated the self-assembly mechanism of CH with FA and improved the value of casein peptides in the food industry.