Primary proteolysis of caseins in cheddar cheese

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dc.contributor.advisor Fox, Patrick F. en McSweeney, Paul L. H. 2014-08-28T09:25:51Z 2014-08-28T09:25:51Z 1993 1993
dc.identifier.citation McSweeney, P. L. H. 1993. Primary proteolysis of caseins in cheddar cheese. PhD Thesis, University College Cork. en
dc.description.abstract Studies were undertaken to investigate proteolysis of the caseins during the initial stages of maturation of Cheddar cheese. Isolated caseins were hydrolyzed by enzymes thought to be of importance during cheese ripening and the resulting peptides isolated and identified. Large peptides were also isolated from Cheddar cheese and identified, thus enabling the extent to which casein degradation studies could be extrapolated to cheese to be established. The proteolytic specificity of chymosin on bovine αs1- and αs2-caseins and of plasmin on bovine αs1-casein were determined. The action of cathepsin D, the principal indigenous acid milk proteinase, on caseins was studied and its pH optimum and sensitivity to NaCI determined. The action of cathepsin D on αs1-, αs2-, β- and κ-caseins was compared with that of chymosin and was found to be generally similar for the hydrolysis of αs1- and κ-caseins but to differ for αs2-and β- caseins. β-Casein in solution was hydrolyzed by cell wall-associated proteinases from three strains of Lactococcus lactis; comparison of electrophoretograms of the hydrolyzates with those of Cheddar cheese indicated that no peptides produced by cell wall-associated proteinases were detectable in the cheeses. All the major peptides in the water-insoluble fraction of Cheddar cheese were isolated and identified. It was found that β-casein was degraded primarily by plasmin and αs1 -casein by chymosin. Initial chymosin and plasmin cleavage sites in αs1-, and β-casein, respectively, identified in these and other studies corresponded to the peptides isolated from cheese. The importance of non-starter lactic acid bacteria (NSLAB) to the maturation of Cheddar was studied in cheeses manufactured from raw, pasteurized or microfiltered milks. NSLAB were found to strongly influence the quality and patterns of proteolysis. Results presented in this thesis are consistent with the hypothesis that primary proteolysis in Cheddar is catalysed primarily by the action of chymosin and plasmin on intact αs1- and β-caseins, respectively. The resulting large peptides so produced are subsequently degraded by these enzymes and by proteinases and peptidases from the starter and NSLAB. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 1993, Paul L. H. McSweeney en
dc.rights.uri en
dc.subject Maturation of Cheddar cheese en
dc.subject Non-starter lactic acid bacteria (NSLAB) en
dc.subject Proteolysis of milk en
dc.subject Proteinases en
dc.subject.lcsh Cheddar cheese en
dc.subject.lcsh Casein en
dc.title Primary proteolysis of caseins in cheddar cheese en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Food Science and Technology) en
dc.internal.availability Full text available en No embargo required en
dc.description.version Accepted Version
dc.description.status Not peer reviewed en Food and Nutritional Sciences en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en

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© 1993, Paul L. H. McSweeney Except where otherwise noted, this item's license is described as © 1993, Paul L. H. McSweeney
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