Identification and analysis of characteristic tryptic peptides from porcine gelatin extracted with multi-stage batch processing

Abstract The extraction process significantly affects the characteristics and identification of gelatins. Here, three porcine gelatins were extracted using multi-stage batch processing by three extraction stages with temperatures of 50, 70, and 90 °C, respectively. Liquid chromatography-high-resolution mass spectrometry was used to investigate differences in the characteristic tryptic peptides derived from three porcine gelatins. Identification by accurate mass and tandem mass spectrometry yielded 97, 88, and 58 characteristic tryptic peptides from porcine gelatin extracted in the first, second, and third stages, respectively. Among these, 46 characteristic tryptic peptides were detected in all porcine gelatin samples. A comparison was then made of gelatins extracted by one-stage processing and those from multi-stage batch processing. Two methods included different extraction times and condition sets, as well as produced various gelatins. These analyses yielded 35 characteristic tryptic peptides, including 8 unmodified peptides from all porcine gelatins recovered from the two extraction methods. Moreover, 27 characteristic peptides showed various modifications with hydroxylation of proline residues. The resultant marker peptides can be highly useful in the accurate identification of porcine gelatins in industrial settings.