antilisterial peptides from spanish dry-cured hams: purification and identification

CASTELLANO PATRICIA; LETICIA MORA ; ELIZABETH ESCUDERO; MELIAN CONSTANZA

Cordoba capital

Congreso; XI congreso argentino de microbiología general SAMIGE; 2015

samige

The production process of Spanish dry-cured ham generally last from 7 to 24?36 months and consists of a stabilizing phase, which includes curing and resting stages at low temperature (wusually below 0.90). However, dry-cured ham is also commercially distributed as sliced ready-to-eat product and post-processing manipulation such as slicing and packaging, enable cross-contamination and serve as a vector for the spread of pathogenic bacteria, such as Listeria monocytogenes. Complex biochemical reactions occur in dry-cured hams process, proteolysis being among the main reaction responsible for the characteristic texture, flavor and final quality of this typical Spanish product. During ripening, muscle proteins are hydrolyzed by muscle enzymes with the release of small peptides and free aminoacids. In this study, a peptidomic strategy has been used to identify and sequence those naturally generated peptides showing antilisterial activity derived from dry-cured ham protein degradation.Water soluble peptide extracts from dry-cured ham were purified by size exclusion chromatography and reversed phase high performance liquid chromatography and then, further identification ofsequences was carried out by nano-liquid chromatography coupled to tandem mass spectrometry. A total of 105 peptide sequences were identified from active fractions. All identified peptides showed a mass between 502 and 2065 Da and amino acid sequences between 5 and 18 amino acids in length.Considering the low molecular mass and structural requirements for antilisterial inhibition, some of the identified peptides were synthesized and their CIM calculated. Eleven peptides were able to inhibit the growth of L. monocytogenes, being the pentapeptide RHGYM the most effective (MIC value: 6.25 mM). Results from this study show that Spanish dry-cured ham may represent a source of naturalpeptides with potential antimicrobial action.