Identification and detection of protein-derived adulterants in oyster peptide powder through an untargeted and targeted proteomics workflow

Oyster peptides are one of the main deep-processing commercial products of oysters, which are generally circulated in the form of peptide powder to preserve and extend the shelf life. The purpose of this study was to qualitatively and quantitatively detect protein-derived adulterants in oyster peptide powder through a combination of untargeted and targeted proteomics strategies. Various peptides derived from non-oyster proteins, mainly collagens of fish, porcine, chicken, and bovine, were detected in the adulterated samples through untargeted proteomics technology. Three signature peptides of gelatin-derived adulterants, namely GPPGKPGP, SGPAGPR, and GPPGPAGPA, were identified and confirmed. On this basis, an MRM-based quantitative method was established using the three signature peptides, which showed good linear relationships with correlation coefficients greater than 0.99 and recovery ranging from 98% to 127%. The established method could quantify the adulteration detection of protein-derived adulterants in oyster peptide powder products, contributing to the quality control of food-derived peptides.