Abstract: This study aimed to identify animal glue in adulterated donkey-hide gelatin. We applied bottom-up proteomics to find and identify characteristic thermostable peptides from different species. Firstly, we found the characteristic peptides from three animal glues (donkey-hide gelatin, pig-hide gelatin and bovine-hide gelatin). At the same time, we also found that the thermostable specific peptides containing no hydroxyproline from the three species were located at similar positions in the α1 sequence of type I collagen. By investigating the sequence characteristics of collagen-derived species-specific peptides, we speculated the cleavage pattern of collagen during the industrial processing of donkey-hide gelatin. Secondly, two characteristic peptides of horse skin, derived from equine keratin and unnamed equine protein, respectively, were used to discriminate horse hide glue from donkey-hide gelatin. In addition to discrimination between donkey-hide gelatin and heterogeneous animal skin glue, this study also provides technical support for the authenticity identification of donkey-hide gelatin and the discovery of more specific peptides from collagen.

Key words: donkey-hide gelatin, proteomics, specific peptide, multiple reaction monitoring, mass spectrometry