Peptides naturally generated from ubiquitin-60S ribosomal protein as potential biomarkers of dry-cured ham processing time

Proteolysis is a complex and dynamic process which takes place throughout the whole dry-cured processing due to the action of endogenous muscle peptidases, and results in the generation of a high number of small peptides and free amino acids responsible for the final quality of dry-cured ham. In this study, a total of sixty-eight peptides derived from the ubiquitin-60S ribosomal protein have been identified in dry-cured ham at 2, 3.5, 5, 6.5, and 9 months of processing using various chromatographic separations and a quadrupole/time-of-flight mass spectrometer in tandem. Some of the identified peptides have been detected during the whole process, whereas a total of fourteen of them were exclusively identified at 9 months of curing. The presence of any of these peptides could be a good indicative that dry-cured ham pieces have reached a minimum curing process of 9 months. The study of the generated peptides has contributed both to a better knowledge of proteolysis evolution and the endogenous enzymes participating, and to determine their potential to be used as quality markers to monitor the processing time. (C) 2013 Elsevier Ltd. All rights reserved.