The superiority of non-gastrointestinal hydrolysis in preparing egg white-derived peptides for orally colitis mitigation: Transepithelial transport and microbiota regulation

Oral food protein-derived peptides for healthcare have attracted increasing attention. However, most animal proteins (e.g., egg white) are highly in vivo digestible into peptides without additional hydrolysis treatment, which poses evident challenges to consumer choices and applications of peptide-based functional food. Herein, egg white-derived peptides prepared by alcalase hydrolysis (APH) and in vitro simulated digestion (SGDP) were compared to investigate the superiority of non-gastrointestinal hydrolysis in preparing peptides. Results indicated that the small peptide (<1 kDa) ratio, proteolysis degree, and sequence diversity of APH were double that of SGDP owing to broader cleavage sites. APH with C-terminal hydrophobic uncharged amino acid residues and higher positivity exhibited admirable advantages in transepithelial transport, contributing to better bioactivities (e.g., antioxidant and anti-inflammatory) and amino acid supplementation. Moreover, APH preferentially enriched mucus- and short-chain fatty acid-associated probiotics, thereby achieving preferable inflammation relief and microbiota restoration. Overall, this study offers an integrated theoretical basis for the superiority of non-gastrointestinal hydrolysis in preparing egg white-derived peptides for healthcare (e.g., colitis relief). Meanwhile, these findings would be enlightening to the development of enzymatic combination strategies and peptide-based ingredients.