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Title:Interactions Among Protein, Electrolytes and Water Determined by Nuclear Magnetic Resonance and Hydrodynamic Equilibria (Nmr)
Author(s):Lioutas, Theodore Stergios
Department / Program:Food Science
Discipline:Food Science
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Food Science and Technology
Abstract:Although salt is an important ingredient in meat products, water binding by muscle protein in the presence of salt has not been investigated. Biceps femoris muscle was dialyzed against distilled water and increasing levels of salt were added to seven aliquots. Sorption and desorption isotherm data at 5(DEGREES)C were obtained. Hysteresis was found only at a(,w) above 0.75 and the degree of hysteresis increased with salt content. Interaction of salt with protein was quantitatively determined in both sorption and desorption modes over a(,w) 0.75 to 0.93 as a function of total salt. Interaction was higher in the desorption mode. Interacted salt increased with salt content; a(,w) affected interaction, especially in the desorption mode.
Proton Nuclear Magnetic Resonance (NMR), in the spin echo technique, was used to determine lysozyme hydration. Results were correlated to 20(DEGREES)C sorption isotherm data. This showed three water components for the isotherm up to 70% water and two additional water populations above this.
Oxygen-17 and deuterium NMR studies of lysozyme hydration are reported for a wide range of lysozyme concentrations, and the relationship between water "activity" and water mobility in the lysozyme-water system as determined by high-field NMR is examined. Good agreement is found between the hydration numbers determined by ('17)O NMR, and the calculations based on the D'Arcy and Watt Theory for three major water populations.
Parallel sorption isotherm, ('17)O and ('7)Li high-field NMR measurements are reported for the system lysozyme-LiCl-D(,2)O. Four distinct water populations are distinguished in this system by an analysis of the sorption isotherms, while the more detailed NMR analyses reveal the presence of an additional water population, corresponding to the solution range. The "monolayer" hydration of lysozyme is increased in the presence of lithium chloride. A maximum number of 10.7 Li('+) moles/mole lysozyme is found to be bound to lysozyme. The lysozyme-NaCl-water system was studies using ('17)O and ('23)Na techniques and results were similar to those obtained with LiCl.
Interactions among myofibrillar proteins, NaCl, and water as shown by sorption and NMR were reported. The salt increased protein hydration. The fraction of salt bound to protein increased with protein concentration.
Issue Date:1984
Description:317 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
Other Identifier(s):(UMI)AAI8502222
Date Available in IDEALS:2014-12-15
Date Deposited:1984

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