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

Ristagno, Diletta

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

dc.check.embargoformat	Not applicable	en
dc.check.info	No embargo required	en
dc.check.opt-out	No	en
dc.check.reason	No embargo required	en
dc.check.type	No Embargo Required
dc.contributor.advisor	McSweeney, Paul L. H.	en
dc.contributor.author	Ristagno, Diletta
dc.contributor.funder	Department of Agriculture, Food and the Marine, Ireland	en
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.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.description.status	Not peer reviewed	en
dc.description.version	Accepted Version
dc.format.mimetype	application/pdf	en
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	https://hdl.handle.net/10468/1390
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.thesis.opt-out	false
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
ucc.workflow.supervisor	p.mcsweeney@ucc.ie