• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Assessment of structure and component mobility within Mozzarella cheese : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Food Technology at Massey University, Manawatu campus, New Zealand

    Icon
    View/Open Full Text
    01_front.pdf (825.7Kb)
    02_whole.pdf (6.490Mb)
    Export to EndNote
    Abstract
    The objective of this study was to identify mechanisms responsible for component mobility relating to structural change within Mozzarella cheese. The use of new techniques alongside well established methods allowed insights to be gained beyond the current understanding of the dynamics within Mozzarella. A number of processing and storage trials were conducted utilising a range of techniques to gain a multi-scale indication of changes in component mobility and structural reorganisation. Dielectric spectroscopy was explored as a method to characterise both ion and water mobility. Initially a model system was utilised as a means of evaluating the technique prior to being applied to Mozzarella. The model system allowed the composition of the cheese to be systematically controlled, especially the calcium. However, subsequent trials (in real Mozzarella cheese systems) indicated that water movement within the cheese during both maturation and heating confound the dielectric response, indicating the method is not ideally suited to measuring a dynamic Mozzarella system. Nuclear magnetic resonance was used to probe changes in component mobility within Mozzarella. Initially well-established relaxation methods were used to monitor the decrease in free water within Mozzarella following manufacture. However, after raising the question of the effect of temperature on free water in cheese, relaxation and diffusion measurements were employed as tools to gain an understanding of the dynamics of water movement within the porous cheese structure. This work was extended further by using these techniques to follow a newly manufactured Mozzarella through a storage trial. The relaxation and diffusion measurements were taken at a range of temperatures at each point of the trial. Phosphorus NMR was explored as a novel approach to monitor changes in the arrangement of calcium and phosphorus (as phosphate) within Mozzarella during storage. This in combination with additional techniques characterising structural changes allowed potential mechanisms for the solubilisation of CCP to be discussed. Collectively these techniques found that Mozzarella undergoes a number of structural changes during storage. Two primary drivers for change were identified from which the other processes cascaded: changing strength in hydrophobic interactions and proteolytic breakdown. Initially the development of the cheese structure was driven primarily by a relaxation in protein matrix (caused by weakening hydrophobic interactions), resulting in the moisture equilibration processes through the associated impact on colloidal calcium phosphate solubility and thus protein-protein interactions. Further structural changes occurred as a result of the proteolytic breakdown of the casein and a possible relaxation in the protein structure. These proteolytic mechanisms dominated maturation behaviour after the moisture equilibration processes were substantially completed (typically >20 days). This thesis revealed new information relating to the movement of components within Mozzarella, particularly at elevated temperatures. These insights will aid in building a more detailed understanding of the dynamics within Mozzarella. It also highlighted several techniques that show promise as potential tools for assessing the structural changes within Mozzarella cheese.
    Date
    2013
    Author
    Smith, Jeremy Robert
    Rights
    The Author
    Publisher
    Massey University
    URI
    http://hdl.handle.net/10179/5209
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1