Evaluation of microbial adjuncts and their effect on the ripening of cheddar cheese

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dc.contributor.advisor McSweeney, Paul L. H. en
dc.contributor.author Ristagno, Diletta
dc.date.accessioned 2014-02-17T15:48:29Z
dc.date.available 2014-02-17T15:48:29Z
dc.date.issued 2013
dc.date.submitted 2013
dc.identifier.citation Ristagno, D. 2013. Evaluation of microbial adjuncts and their effect on the ripening of cheddar cheese. PhD Thesis, University College Cork. en
dc.identifier.endpage 219
dc.identifier.uri http://hdl.handle.net/10468/1390
dc.description.abstract A bacteriocin-producing strain of Lactobacillus paracasei DPC 4715 was used as an adjunct culture in Cheddar cheese in order to control the growth of “wild” nonstarter lactic acid bacteria. No suppression of growth of the indicator strain was observed in the experimental cheese. The bacteriocin produced by Lactobacillus paracasei DPC 4715 was sensitive to chymosin and cathepsin D and it may have been cleaved by the rennet used for the cheese manufactured or by indigenous milk proteases. A series of studies were performed using various microbial adjuncts to influence cheese ripening. Microbacterium casei DPC 5281, Corynebacterium casei DPC 5293 and Corynebacterium variabile DPC 5305 were added to the cheesemilk at level of 109 cfu/ml resulting in a final concentration of 108 cfu/g in Cheddar cheese. The strains significantly increased the level of pH 4.6-soluble nitrogen, total free amino acids after 60 and 180 d of ripening and some individual free amino acids after 180 d. Yarrowia lipolytica DPC 6266, Yarrowia lipolytica DPC 6268 and Candida intermedia DPC 6271 were used to accelerate the ripening of Cheddar cheese. Strains were grown in YG broth to a final concentration of 107 cfu/ml, microfluidized, freeze-dried and added to the curd during salting at level of 2% w/w. The yeasts positively affected the primary, secondary proteolysis and lipolysis of cheeses and had aminopeptidase, dipeptidase, esterase and 5’ phosphodiestere activities that contributed to accelerate the ripening and improve the flavor of cheese. Hafia alvei was added to Cheddar cheesemilk at levels of 107 cfu/ml and 108 cfu/ml and its contribution during ripening was evaluated. The strain significantly increased the level of pH 4.6-soluble nitrogen, total free amino-acids, and some individual free amino-acids of Cheddar cheese, whereas no differences in the urea-polyacrylamide gel electrophoresis (urea-PAGE) electrophoretograms of the cheeses were detected. Hafia alvei also significantly increased the level of some biogenic amines. A low-fat Cheddar cheese was made with Bifidobacterium animalis subsp. lactis, strain BB-12® at level of 108 cfu/ml, as a probiotic adjunct culture and Hi-Maize® 260 (resistant high amylose maize starch) at level of 2% and 4% w/v, as a prebiotic fiber which also played the role of fat replacer. Bifidobacterium BB-12 decreased by 1 log cycle after 60 d of ripening and remained steady at level of ~107 cfu/g during ripening. The Young’s modulus also increased proportionally with increasing levels of Hi-maize. Hencky strain at fracture decreased over ripening and increased with increasing in fat replacer. A cheese based medium (CBM) was developed with the purpose of mimicking the cheese environment at an early ripening stage. The strains grown in CBM showed aminopeptidase activity against Gly-, Arg-, Pro- and Phe-p-nitroanalide, whereas, when grown in MRS they were active against all the substrates tested. Both Lb. danicus strains grown in MRS and in CBM had aminotransferase activity towards aromatic amino acids (Phe and Trp) and also branched-chain amino acids (Leu and Val). Esterase activity was expressed against p-nitrophenyl-acetate (C2), pnitrophenyl- butyrate (C4) and p-nitrophenyl-palmitate (C16) and was significantly higher in CBM than in MRS. en
dc.description.sponsorship Department of Agriculture, Food and the Marine (Food Institutional Research Measure) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2013, Diletta Ristagno. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Cheese ripening en
dc.subject Non starter lactic acid bacteria en
dc.subject Microbial adjuncts en
dc.subject Microbial enzymes en
dc.subject.lcsh Cheddar cheese en
dc.subject.lcsh Lactic acid bacteria en
dc.title Evaluation of microbial adjuncts and their effect on the ripening of cheddar cheese en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Dairy Science) en
dc.internal.availability Full text available en
dc.check.info No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Department of Agriculture, Food and the Marine, Ireland en
dc.description.status Not peer reviewed en
dc.internal.school Food and Nutritional Sciences en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out No en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
ucc.workflow.supervisor p.mcsweeney@ucc.ie
dc.internal.conferring Autumn Conferring 2013 en

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© 2013, Diletta Ristagno. Except where otherwise noted, this item's license is described as © 2013, Diletta Ristagno.
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