Occurrence of non-proteolytic amino acyl derivatives in dry-cured ham

Proteolysis is the most important event occurring during maturation of dry-cured hams: it strongly influences the flavour and the texture of the aged ham by the accumulation of peptides and free amino acids released by protein hydrolysis. Apart from compounds of proteolytic origin, it has been demonstrated that also non-proteolytic amino acyl derivatives (γ-glutamyl amino acids, pyroglutamyl-amino acids and lactoyl-amino acids) may accumulate during ripening of cheese, and they can be also found in fermented soy sauce, where they contribute to the umami taste of the products. Using a semi-quantitative analysis, in this paper we report the occurrence of significant amounts of γ-glutamyl amino acids and, for the first time, pyroglutamyl-amino acids and lactoyl-amino acids, in aged ham. The amino acid counterparts were mainly found to be hydrophobic amino acids. The amount of these compounds was found to increase with time, because they are not degraded by proteolytic activity. They were also found to be stable to simulated gastrointestinal digestion. Angiotensin Converting Enzyme inhibitory activity was also tested, but they were not found to be characterized by significant ACE-inhibitory activity.