Peptides identified during Emmental cheese ripening: origin and proteolytic systems involved.
To determine the proteolytic changes occurring during Emmental cheese ripening, peptides released in cheese aqueous phase were analyzed by reversed-phase HPLC and identified by tandem mass spectrometry sequencing, for which different strategies were illustrated by some examples. Among the 91 peptides identified, most of them arose from alpha(s1)- (51) and beta-caseins (28), and a few arose from alpha(s2)- (9) and kappa-caseins (1). An attempt was made to correlate the released peptides with the proteolytic systems potentially involved during Emmental cheese manufacture. Besides the well-known action of plasmin on beta- and alpha(s2)-caseins, and in the absence of residual fungal coagulant from Endothia parasitica, two other proteinases seem to be involved in the hydrolysis of alpha(s1)-casein in Emmental cheese: cathepsin D originated from milk and cell-envelope proteinase from thermophilic starters. Moreover, peptidases from starters were also active throughout ripening, presumably like those from nonstarter lactic acid bacteria, in contrast to those from propionic acid bacteria.
Gagnaire
V
V
Laboratoire de Recherche et de Technologie laitière, Institut National de la Recherche Agronomique, 65 rue de Saint Brieuc, 35042 Rennes Cedex, France. gagnaire@rennes.inra.fr
Mollé
D
D
Herrouin
M
M
Léonil
J
J
D002364:Caseins / Q000378:metabolism*; D002611:Cheese / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D005341:Fibrinolysin / Q000378:metabolism; D005511:Food Handling; D013058:Mass Spectrometry; D010447:Peptide Hydrolases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D013997:Time Factors
D002364:Caseins; D011506:Proteins; D010447:Peptide Hydrolases; D005341:Fibrinolysin