Rheological properties of gel

Like the transitional physical properties, the rheological properties of gels are not easily characterized because they depend strongly on the attributes of the polymer, history of the gel sample, and experimental conditions. Most often, the apparent viscosity or gel... 

Pons R, Solans C, Stebe MJ, Erra P, Ravey JC. Stability and rheological properties of gel emulsions. Progr Colloid Polym Sci 1992 89 110-113. 

Creates protein cross-links to improve rheological properties of gels, i.e., surimi, gelatin... 

A characteristic feature of a gel is its elastic behavior the gel deforms by an imposed force and it relaxes to its original state after releasing the force. Elastin, a crosslinked polypeptide network takes care of the elasticity of human and animal connective tissues, such as skin, ligaments, and arterial walls. For a more extensive discussion on the rheological properties of gels, the reader is referred to Chapter 17. 

Xanthan does not in itself form gels, despite the strong intermolecular interactions which occur in solution. However, some of the rheological properties of xanthan have... 

Investigations of the influence of various cations on the rheological properties of high-esterified pectin gels... 

H. Muller, W. Breuer, C. P. Herold, P. Kuhm, and S. von Tapavicza. Mineral additives for setting and/or controlling the rheological properties and gel structure of aqueous liquid phases and the use of such additives. Patent US 5663122,1997. 

The results of these tests and the fluid formulations axe shown in Table IV. The adverse effect on fluid rheology of adding potassium, KC1, Test B, and TKPP, Test C, is evident. Both salts cause increases in yield point, YP, and initial gel strength. TKPP produced only about half as much increase as did KC1 and can be added in much higher concentrations before the rheological properties of the drilling mud become unacceptable. 

Thus, the mechanisms of gelation determine the structure of the network, and consequently, the rheological properties of the gels. 

Bikker, J.F., Anema, S.G., Li, Y., Hill, J.P. (2000). Rheological properties of acid gels prepared front heated milk fortified with whey protein mixtures containing the A, B and C variants of p-lactoglobulin. International Dairy Journal, 10, 723-732. 

Dickinson, E., Matia-Merino, L. (2002). Effect of sugars on the rheological properties of acid caseinate-stabilized emulsion gels. Food Hydrocolloids, 16, 321-331. 

The term food colloids can be applied to all edible multi-phase systems such as foams, gels, dispersions and emulsions. Therefore, most manufactured foodstuffs can be classified as food colloids, and some natural ones also (notably milk). One of the key features of such systems is that they require the addition of a combination of surface-active molecules and thickeners for control of their texture and shelf-life. To achieve the requirements of consumers and food technologists, various combinations of proteins and polysaccharides are routinely used. The structures formed by these biopolymers in the bulk aqueous phase and at the surface of droplets and bubbles determine the long-term stability and rheological properties of food colloids. These structures are determined by the nature of the various kinds of biopolymer-biopolymer interactions, as well as by the interactions of the biopolymers with other food ingredients such as low-molecular-weight surfactants (emulsifiers). 

Gels are viscoelastic bodies, the rheological properties of which can be described by two parameters, the storage modulus (G, which is a measure of its elasticity) and the loss modulus (G", which is a measure of its viscous nature). The combined viscoelastic modulus (G ) is a measure of the overall resistance of a gel to deformation. These moduli are often highly dependent on the time-scale of deformation. Another important parameter of a food gel is its yield stress. 

Ziegler and Foegeding, 1990. See above. Extensively reviews the rheological properties of various protein gels. Also includes an introduction to gelation theories. 

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