Generation of kokumi γ-glutamyl short peptides in Spanish dry-cured ham during its processing

The typical dry-cured ham flavor is rich in umami and brothy perceptions, for which short peptides may contribute. Particularly, gamma glutamyl peptides could be the responsible of these previously reported attributes, as they exert a synergistic interaction with other basic tastes and modify the intensity of salty, sweet, and umami tastes. The content of peptides has been reported to evolve along the processing, but no kokumi gamma-glutamyl peptides have been identified in Spanish dry-cured hams yet. In this research, nine gamma-glutamyl dipeptides (gamma-EA, gamma-EC, gamma-EE, gamma-EF, gamma-EL, gamma-EM, gamma-EV, gamma-EW, and gamma-EY) and two gamma-glutamyl tripeptides (GSH and gamma-EVG) have been quantitated at 6, 12, 18 and 24 months of traditional processing of Spanish dry-cured ham by performing a Q Exactive Orbitrap-based tandem mass spectrometry. The results show an increase of gamma-EA, gamma-EE, gamma-EF, gamma-EL, gamma-EM and gamma-EVG, obtaining maximums at 24 months of curing ranging from 0.14 (gamma-EVG) to 18.86 (gamma-EL) mu g/g dry-cured ham. Otherwise, gamma-EV, gamma-EW and gamma-EY accumulated until the 18th month of storage to 15.10, 0.54 and 3.17 mu g/g dry-cured ham, respectively; whereas gamma-EC and GSH amounts decreased starting from 0.0676 and 4.41 mu g/g dry-cured ham, respectively at earlier stages. The concentration dynamics of these compounds may be linked with proteolytic and oxidative reactions during processing. In addition, due to their synergistic effect on kokumi activity, this could constitute insights of the brothy perceptions of dry-cured ham, and these peptides probably contribute to the sensory differences existing in long processed Spanish dry-cured hams.