The effect of steam cooking on the proteolysis of pacific oyster (Crassostrea gigas) proteins: Digestibility, allergenicity, and bioactivity

This study aimed to investigate the effect of steam cooking on the proteolysis of Pacific oysters (Crassostrea gigas) using the simulated oral-gastrointestinal digestion model and a NCM460 cell monolayer. Steam cooking changed the peptide profile of the digests of oysters considerably and induced more thorough hydrolysis. However, the heat-stable allergen, Cra g 1, still had remnant fragments in the intestinal phase, which could be allergenic epitopes. Two regions of Cra g 1 (residues 224-228 and 245-248) were digestion-tolerant. Furthermore, more oligopeptides were derived from raw proteins than from steamed proteins. After molecular docking and in vitro determination, six novel angiotensin I-converting enzyme inhibitory (ACEi) peptides were finally identified in the hydrolysates (WIS, WLS, LSL, SGPF, LGPI, and IGLP). Among them, LSL exhibited the highest ACEi activity (IC50 = 107.17 nM). Our findings provide supportive information on the effective utilization of oyster proteins.