What is colloidal dispersion in food?
Colloidal dispersion is a two phase system in which the particles in the dispersed phase are between 1 and 100 nm in diameter. For this reason, most manufactured foods can be considered as food colloids and many contain hydrocolloids that are added to control stability and rheological properties.
What are the factors that contributed to the stability of a colloidal system?
The stability of colloidal solutions varies in a very wide range: their life lasts from fractions of a second to hundreds of years. It depends on many factors: particles’ size and concentration, process temperature, presence of electrolytes.
What is depletion attraction?
A depletion force is an effective attractive force that arises between large colloidal particles that are suspended in a dilute solution of depletants, which are smaller solutes that are preferentially excluded from the vicinity of the large particles.
What are the factors that contributed to the stability of a colloidal system why are they important in maintaining the stability of a colloidal system?
The stability of colloidal suspensions depends, therefore, crucially on quantities such as surface tension, electrostatic interactions involving surface charges of the solute and the electrolyte content of the solvent, and van der Waals interactions.
What are the 3 types of colloidal systems?
On the basis of the type and extent of molecular interactions of the dispersed phase with the dispersion medium, colloidal systems can be classi-fied into three groups: lyophilic, lyophobic, and association colloids.
What type of colloid is cake?
3 Classification of Colloids
| Dispersed Phase | Dispersant Phase | Example |
|---|---|---|
| Gas | Liquid | Foam on beer, bubbles in sparkling wine, whipped cream |
| Liquid | Liquid | Mayonnaise, milk, vinaigrette |
| Solid | Liquid | Whitewash, skimmed milk, paints, puddings, jelly, mud |
| Gas | Solid | Meringue, ice cream, bread, sponge cake |
How do you stabilize a colloid system?
Stability improvement can be achieved through either increasing repulsion or decreasing attraction between colloidal particles. Two traditional mechanisms for colloidal stability are electrostatic stabilization and steric stabilization.
How do you stabilize colloids?
Polymeric stabilization of colloids Steric stabilization of colloids is achieved by polymer molecules attached to the particle surface and forming a coating, which creates a repulsive force and separates the particle from another particle.
How is depletion force calculated?
The depletion force depends on the number density ρ = N/V and absolute temperature T of the sur- rounding liquid, which was treated as an ideal gas. The physical origin of the depletion force is that the overlap of the restricted volumes of the plates increases the volume accessible to small spheres.
Which property is largely responsible in providing stability to the colloidal solution?
The presence of equal and similar charges on colloidal particles is largely responsible in providing stability to the colloidal solution. Thus, zeta potential is a key indicator of the stability of colloidal dispersions.
What is the depletion force in colloids?
Introduction The depletion force [1] is central to issues of colloidal stability [2, 3, 4]; it arises between large spheres suspended in a dilute solution of nonadsorbing polymers, micelles, or smaller hard spheres. The last case is amenable to detailed analysis (at least at low densities) [1, 5, 6], and serves as a model for the others.
How are colloids and depletants in solution modeled?
The system of colloids and depletants in solution is typically modeled by treating the large colloids and small depletants as dissimilarly sized hard spheres. Hard spheres are characterized as non-interacting and impenetrable spheres. These two fundamental properties of hard spheres are described mathematically by the hard-sphere potential.
What is colloidal system in food?
In this article we will discuss about:- 1. Classification and Functions of Colloidal Systems in Food 2. Types of Colloidal System in Food 3. Stability. A colloid is a type of chemical mixture where one substance is dispersed evenly throughout another.
What is the depletion force of the particles at separation?
A force balance of the particles at separation can be used to determine the depletion force between the particles. Depletion forces are used extensively as a method of destabilizing colloids.