Uncommonly thorough hydrolysis of peptides during ripening of Ragusano cheese revealed by tandem mass spectrometry.
Ragusano is a pasta filata cheese produced from raw milk in Sicily. The proteolysis was extensively analyzed after stretching (day 0), at 4 and 7 months of ripening through soluble nitrogen, urea-PAGE, and peptide identification by tandem mass spectrometry. After stretching, 123 peptides were identified: 72 arising from β-casein, 34 from α(s1)-casein, and 17 from α(s2)-casein. The main protein splitting corresponded to the action of plasmin, chymosin, cathepsin D, cell envelope proteinase, and peptidase activities of lactic acid bacteria. Unlike other types of cheeses, <10% residual β- and α(s)-caseins remained intact at 7 months, indicating original network organization based on large casein fragments. The number of identified soluble peptides also dramatically decreased after 4 and 7 months of ripening, to 47 and 25, respectively. Among them, bioactive peptides were found, that is, mineral carrier, antihypertensive, and immunomodulating peptides and phosphopeptides.
UMR 1253, INRA, Science et Technologie du Lait et de l'Œuf, 65 rue de Saint Brieuc, F-35042 Rennes, France. valerie.gagnaire@rennes.inra.fr
Valérie
V
Gagnaire
Stefania
S
Carpino
Concetta
C
Pediliggieri
Julien
J
Jardin
Sylvie
S
Lortal
Giuseppe
G
Licitra
D000595:Amino Acid Sequence; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D002611:Cheese / Q000032:analysis*; D055598:Chemical Phenomena; D002851:Chromatography, High Pressure Liquid; D005511:Food Handling / Q000379:methods; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000032:analysis* / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
D002364:Caseins; D010455:Peptides; D010447:Peptide Hydrolases