Gelation


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Related to Gelation: gelation time

gelation

[jə′lā·shən]
(chemistry)
The act or process of freezing.
Formation of a gel from a sol.

Gelation

 

the transformation of a readily mobile or viscous fluid into a solid (a body without fluidity) that is elastic, plastic, and brittle. Gelation is characteristic of solutions of macromolecular compounds and of disperse colloidal systems. It is caused by the formation of a three-dimensional structural network (skeleton), which fills the entire volume of the liquid and destroys its mobility. In solutions of polymers such a network is formed from macromolecules linked by intermolecular forces or chemical bonds; in colloidal systems, it is formed from coupled particles of the dispersed phase.

Gelation may be caused by an increase or decrease in temperature, an increase in the concentration of the dissolved or dispersed material, a change in chemical composition of the system as a result of a chemical reaction between its components, or the introduction of specific reagents. Gelation is sometimes reversible— that is, when conditions change, a system may pass repeatedly from the liquid state to the solid state and vice versa. However, in the case of pro-found chemical or physical changes in a system, the process is irreversible.

Gelation is often observed and plays an important role in many natural and manufacturing processes. The liquid layer of a paint, lacquer, glue, or photographic emulsion gelates before finally drying. Gelation occurs upon the introduction of electrolytes into rubber latex, during the hardening of synthetic resins in the manufacture of plastics, during the cooling of gelatin and starch paste solutions, and during the coagulation of blood.

References in periodicals archive ?
Consequently, changes in characteristics of the intrinsic muscle proteins were possibly an important factor in causing weaker thermal gelation ability and WHC of PSE-like meat.
Keeping in view the gelation behavior of [alpha]-amino acid, we have carried out present studies to investigate the potential of N-acetylglycine, the least studied [alpha]-amino acid, as organogelator by providing aromatic and aliphatic spacer.
The 7S and 11S protein fractions of CPS presents large molar mass compared to P-lactoglobulin and can produce different effects on the porosity of microparticles obtained by ionic gelation after adsorption of protein on the microparticles (WANDREY et al., 2010).
Besides, well studies have been done to investigate the gelation and vitrification mechanisms that affect membrane morphologies.
The gelation temperature was recorded when the formulation stops flowing upon test tube inversion.
Sequently, hydrochloric acid (HCl) was used to adjust the pH of the gelling solutions to 7 because the gelation process is optimum in neutral condition.
Ipsen, "Physicochemical properties of milk protein ingredients and their acid gelation behaviour in different ionic environments," International Dairy Journal, vol.
Heat Gelation. Heat gelation is done by heating whey protein solution sample at gelation temperature until denaturation and aggregation occur.
One goal of the study was to determine how crosslinking and pH variations affect the cell viability of chondrocytes and the mechanics, gelation kinetics and printability of collagen bioinks.
Table 4 summarized the least gelation concentration of [beta]-glucan.
The choice of such polymer concentrations was due to the fact that when [C.sub.CS] > 1% (w/v) chitosan accelerates gelation in weakly acidic media [34].
Gelation time was recorded when the solution lost its fluidity.