Plastein reaction with exogenous tryptophan addition as a promissing strategy to enhance the bioactivity and digestive stability of chicken peptides.

Instability during gastrointestinal digestion is one of the key factors that limiting further application of bioactive peptides. Plastein reaction is considered an effective strategy to enhance the bioactivity and digestive of peptides, especially introducing specific amino acid with favorable activity. In this study, chicken peptides (CP) were subjected to plastein reaction with exogenous Trp addition, aiming to improve the bioactivity and digestive stability. Results showed that, after Alcalase-catalyzed plastein reaction with 5% Trp addition, the ADH-stabilizing activity and ABTS radical scavenging activity of CP increased to 134.68 ± 0.64% and 241.10 ± 2.95%, compared with non-reacted CP. Moreover, the plastein reaction product exhibited higher activity than CP after simulated gastrointestinal digestion, indicating the improved digestive stability. Peptidomics analysis resulted in 64 potential bioactive peptides with strong hydrogen-bonding and hydrophobic capacities among the 1711 identified peptides,including 6 newly generated Trp-containing peptides (LWG, TLW, VVWF, WAF, WLL, and WTL). Analysis of the correlations among surface structure, secondary structure, driving forces, and peptidome revealed that hydrolysis, condensation, and transpeptidation during plastein reaction could lead to the generation of Trp-containing peptides and other peptides with strong hydrogen-bonding and hydrophobic interaction potential, driving the formation of more stable β-sheet structure in CP, thereby improving both bioactivity and digestive stability. The results obtained indicated that plastein reaction with Trp addition can enhance the ADH-stabilizing activity, antioxidant capacity, and digestive stability of chicken peptides, offering a promising strategy for producing more bioactive and stable peptides preventing against alcoholic liver injury.