Deamidation post-translational modification in naturally generated peptides in Spanish dry-cured ham

A large number of peptides are generated during the processing of dry-cured ham that can be affected by post-translational modifications (PTM). One of the most studied PTMs is the oxidation of susceptible residues but other modifications such as deamidation have been scarcely reported in the literature. This work has been focused on the impact of deamidation in those peptides generated in 12-months dry-cured hams. The results obtained in Biceps femoris and Semimembranosus muscles showed that 52% and 48% of the identified peptides, respectively, were affected by PTMs, with a total of 277 and 282 sequences showing deamidation in both muscles, respectively. It appears that deamidation is not influenced by the type of muscle but is probably favored by characteristic processing conditions like temperature, pH, and salting of hams. The knowledge of the affected sequences provides novel information for a better characterisation of proteolysis phenomena during the processing of dry-cured ham.