Generation and characterisation of biologically active milk-derived protein and peptide fractions

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dc.contributor.advisor McSweeney, Paul L. H. en
dc.contributor.advisor Kelly, Alan en McGrath, Brian Andrew 2015-08-11T15:55:35Z 2014 2014
dc.identifier.citation McGrath, B. A. 2014. Generation and characterisation of biologically active milk-derived protein and peptide fractions. PhD Thesis, University College Cork. en
dc.identifier.endpage 420
dc.description.abstract In recent years, extensive research has been carried out on the health benefits of milk proteins and peptides. Biologically active peptides are defined as specific protein fragments which have a positive impact on the physiological functions of the body; such peptides are produced naturally in vivo, but can also be generated by physical and/or chemical processes, enzymatic hydrolysis and/or microbial fermentation. The aims of this thesis were to investigate not only the traditional methods used for the generation of bioactive peptides, but also novel processes such as heat treatment, and the role of indigenous milk proteases, e.g., in mastitic milk, in the production of such peptides. In addition, colostrum was characterised as a source of bioactive proteins and peptides. Firstly, a comprehensive study was carried out on the composition and physical properties of colostrum throughout the early-lactation period. Marked differences in the physico-chemical properties of colostrum compared with milk were observed. Various fractions of colostrum were also tested for their effect on the secretion of pro- and anti-inflammatory cytokines from a macrophage cell line and bone marrow dendritic cells, as well as insulin secretion from a pancreatic beta cell line. A significant reduction in the secretion of the pro-inflammatory cytokines, TNF-α, IL-6, IL-1β and IL-12, a significant increase in the secretion of the anti-inflammatory cytokine, IL-10, as well as a significant increase in insulin secretion were observed for various colostrum fractions. Another study examined the early proteomic changes in the milk of 8 cows in response to infusion with the endotoxin lipopolysaccharide (LPS) at quarter level in a model mastitic system; marked differences in the protein and peptide profile of milk from LPS challenged cows were observed, and a pH 4.6-soluble fraction of this milk was found to cause a substantial induction in the secretion of IL-10 from a murine macrophage cell line. Heat-induced hydrolysis of sodium caseinate was investigated from the dual viewpoints of protein breakdown and peptide formation, and, a peptide fraction produced in this manner was found to cause a significant increase in the secretion of the anti-inflammatory cytokine, IL-10, from a murine macrophage cell line. The effects of sodium caseinate hydrolysed by chymosin on the gut-derived satiety hormone glucagon-like peptide-1 (GLP-1) were investigated; the resulting casein-derived peptides displayed good in vitro and in vivo secretion of GLP-1. Overall, the studies described in this thesis expand on current knowledge and provide good evidence for the use of novel methods for the isolation, generation and characterisation of bioactive proteins and/or peptides. en
dc.description.sponsorship Enterprise Ireland (Grant Number CC20080001) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Brian A. McGrath en
dc.rights.uri en
dc.subject Biologically active en
dc.subject Milk-derived en
dc.subject Protein fractions en
dc.subject Peptide fractions en
dc.title Generation and characterisation of biologically active milk-derived protein and peptide fractions 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 not available en Restricted to everyone for five years en 2020-08-09T15:55:35Z
dc.description.version Accepted Version
dc.contributor.funder Food for Health Ireland en
dc.contributor.funder Enterprise Ireland en
dc.description.status Not peer reviewed en Food and Nutritional Sciences en Food For Health Ireland en
dc.check.reason Releasing this thesis would cause substantial prejudice to the commercial interests of the sponsor of the postgraduate research en
dc.check.opt-out Yes en
dc.thesis.opt-out true
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en
dc.internal.conferring Summer Conferring 2014

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© 2014, Brian A. McGrath Except where otherwise noted, this item's license is described as © 2014, Brian A. McGrath
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