- Title
- Unexpected high pressure effects on the structural properties of condensed whey protein systems
- Creator
- Dissanayake, Muditha; Kasapis, Stefan; Chaudhary, Vinita; Adhikari, Benu; Palmer, Martin; Meurer, Barbara
- Date
- 2012
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/69267
- Identifier
- vital:4766
- Identifier
-
https://doi.org/10.1002/bip.22112
- Identifier
- ISSN:0006-3525
- Abstract
- We show that application of high hydrostatic pressure (600 MPa for 15 min) on condensed whey protein (WP) systems (e.g., 80% w/w solids content) results in unexpected structure-function behavior when compared with conventional thermal treatment. Unraveling the relaxation properties in first-order thermodynamic transitions, the manifestation of glass transition phenomena and the preservation of native conformation in condensed preparations were recorded using small-deformation dynamic oscillation in shear, modulated differential scanning calorimetry, and infrared spectroscopy. Informed temperature application results in the formation of continuous networks at the denaturation temperature, which undergo vitrification at subzero temperatures. In contrast, high-pressure-treated WPs resist physicochemical denaturation, hence preserving the native conformation of secondary and tertiary structures. This was rationalized on the basis of a critical concentration threshold where transfer of water molecules to nonpolar residues in the protein interior is minimized because of low moisture content and restricted molecular mobility. The physical state and morphology of these high-solid preparations were further examined by the combined framework of reduced variables and Williams, Landel, and Ferry equation/free volume theory. Theoretical treatment of experimental observations unveils the dynamic range of the mechanical manifestation of the glass transition region in samples subjected to heat or pressure. In addition to preserving native conformation, WPs subjected to high pressure form glassy systems at parity with the structural functionality of the thermally treated counterparts. © 2012 Wiley Periodicals, Inc.
- Relation
- Biopolymers Vol. 97, no. 12 (2012), p. 963-973
- Rights
- Copyright 2012 Wiley Periodicals, Inc.
- Rights
- This metadata is freely available under a CCO license
- Subject
- Small deformation rheology; Critical concentration; Deformation rheology; Denaturation temperatures; Dynamic oscillations; Glass transition phenomena; Glassy systems; High hydrostatic pressure; High-pressure form; Modulated differential scanning calorimetry; Molecular mobility; Solids content; Structural functionality; Theoretical treatments; Transition regions; Water molecule; Whey proteins; Infrared spectroscopy; Temperature; Proteins; Morphology; Vitrification; 03 Chemical Sciences; 06 Biological Sciences
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