Comparative peptidomic profile and bioactivities of Pacific oyster, Mytilus edulis, Argopecten irradians, Meretrix meretrix L. after simulated gastrointestinal digestion

Purpose This study investigated the basic composition, in vitro digestibility, biological activities, and potential bioactive peptides of Pacific oyster (PO), Mytilus edulis (ME), Argopecten irradians (AIS), and Meretrix meretri x L. (MML) after simulated gastrointestinal digestion (SGD). Methods SGD products were prepared using the INFOGEST 2.0 model, and their nutritional properties and biological activities were analyzed. A comprehensive peptidomic profiling of the digested samples was conducted using nano-liquid chromatography-tandem mass spectrometry (nano-LC MS/MS) analysis. Results All four shellfish exhibited a nutritional profile characterized by high protein and low-fat content. The digestibility of shellfish increased progressively, while the average molecular weight (MW) of the hydrolysates gradually decreased during SGD, with the intestinal hydrolysates showing the highest overall digestibility. Biological activity analysis demonstrated that intestinal digestion products from all four species exhibited notable ABTS radical scavenging activity and α-glucosidase inhibition activity, with PO and ME exhibiting the strongest effects. A total of 349, 99, 314 and 105peptides were identified from the digestion products of PO, ME, AIS, and MML, respectively. Among these, PO and AIS showed the highest sequence similarity, sharing 69 identical peptides. By contrast, MML displayed distinct peptidomic characteristics, including a higher proportion of large MW peptides. Conclusion This study provides a comprehensive peptide catalog of shellfish digestion products and offers new insights into the biological activities of shellfish-derived peptides, supporting their potential as functional food resources.