Marker peptide combination for source identification of gelatins obtained from Equidae hides by LC–MS/MS detection

Abstract

Gelatin, which is a soluble, natural polymer produced by partial hydrolysis of collagens, has been extensively used in food and pharmaceuticals. Donkey-hide gelatin is a well-known traditional Chinese medicine. The certification of donkey-hide gelatin is one of the most concerned issues for consumers. Currently, the source identification of the homologous family species, including donkey, horse and their hybrids, remains a major challenge. Here, three peptides (SGQPGTVGPAGVR, GASGPAGVR and GATGPAGVR) of the equine family species were screened using high-resolution LC-MS. The combination of these three peptides has been used as a high-performance marker in LC-MS/MS to identify the animal source (donkey, horse, and their hybrids) of donkey-hide-gelatin-containing products. Horse-hide gelatin and hybrid-hide gelatin can be detected in gelatin-based products even at very low percentages (0.05% and 0.10%, respectively). The marker peptide combination method is useful for source identification of homologous family species and is not only highly sensitive but also rapid.