Combined Peptidomics and Metabolomics Analyses to Characterize the Digestion Properties and Activity of Protein-Peptide-Based Materials.

Protein-peptide-based materials typically possess high nutritional value and various physiological regulatory activities. This study evaluated the digestion, metabolism, and activity of protein-peptide-based materials. After the protein-peptide-based materials were digested (simulated) orally, in the stomach, and in the intestines, the proportions of >10,000 Da, 500010,000 Da, and <180 Da in the digestion products increased, and the peptide content was maintained at more than 120 mg/g dry weight. The digestion products of eight test groups with different oral-gastrointestinal digestion-level settings all had suitable ACE inhibitory activity (IC range 0.0040.096 mg/mL). The main metabolite groups were lipid-like molecules, fatty acids, carboxylic acids, their derivatives, amino acids, peptides, and analogs. Bile and glycosylated amino acids were the main compounds that caused differences between groups. KEGG pathways enriched in differentially expressed metabolites included eight significantly upregulated pathways, including valine, leucine, and isoleucine biosynthesis, etc., and six significantly downregulated pathways, including the citric acid cycle (tricarboxylic acid cycle), etc. The arginine and proline metabolism pathways and the aminoacyl-tRNA biosynthesis pathways were upregulation and downregulation pathways that enriched multiple differentially expressed metabolites. Twenty-six metabolites, including bile acids, total bile acids, and the essential amino acids L-isoleucine and L-leucine, were differentially expressed metabolite markers of the protein-peptide-based material oral-gastrointestinal digestion products.