Colloidal System
Colloidal
system is an intimate mixture of two substances, one of which called the
dispersed phase (or colloid), is uniformly distributed in a finely divided
state through the second substance called the dispersion medium (or dispersing
medium. Colloidal system is a heterogenous system which is made up of dispersed
phase and dispersion medium.
system is an intimate mixture of two substances, one of which called the
dispersed phase (or colloid), is uniformly distributed in a finely divided
state through the second substance called the dispersion medium (or dispersing
medium. Colloidal system is a heterogenous system which is made up of dispersed
phase and dispersion medium.
Example of Colloidal System in Food
1.
Foam
Foam
2.
Emulsions
Emulsions
3.
Gel
Gel
4.
Sol
Sol
5.
Liquid
Aerosol
Liquid
Aerosol
6.
Solid
Aerosol
Solid
Aerosol
|
Class
|
Disperse Phase
|
Disperse Medium
|
Example
|
|
|
1.
|
Foam
|
Gas
|
Liquid
|
Beaten
egg, Froths, Whipped Cream |
|
2.
|
Emulsions
|
Liquid
|
Liquids
|
Milk,
Butter, Mayonaise, Asphalt, Phamaceutical creams |
|
3.
|
Gels
|
Macromolecule
|
Solvent
|
Colloids
jellies,glue butter, cheese |
|
4.
|
Sol
|
Solid
|
Liquids
|
Pasteink
paint. |
|
5.
|
Solid
|
Solid
|
Gas
|
Industrial
smokes dust |
|
6.
|
Liquid
Aerosol |
Liquid
|
Gas
|
Mist
tobacco smoke “aerosol sprays, frog, dust |
Types of Colloidal System in Food
1. Foam: a foam is a dispersion of gas bubbles in a liquid
or semisolid phase in the colloidal dispersion, gas forms the dispersed phase
and liquid is the disperse medium. Foams used in cookery include froths,
whipped cream, beaten egg white. We have two type of foams.
or semisolid phase in the colloidal dispersion, gas forms the dispersed phase
and liquid is the disperse medium. Foams used in cookery include froths,
whipped cream, beaten egg white. We have two type of foams.
·
Gas in Liquid
Gas in Liquid
·
Gas in Solid
Gas in Solid
2. Emulsion:
an emulsion is a colloidal dispersion of tiny
droplets if one liquid suspended in another, in this colloidal system, liquids
form the dispersed as well as the disperse medium. One liquid is dispersed in
as droplets in another liquid. Emulsion form only when two liquids are
immiscible in each other. Examples of emulsion are milk, butter, mayonnaise.
an emulsion is a colloidal dispersion of tiny
droplets if one liquid suspended in another, in this colloidal system, liquids
form the dispersed as well as the disperse medium. One liquid is dispersed in
as droplets in another liquid. Emulsion form only when two liquids are
immiscible in each other. Examples of emulsion are milk, butter, mayonnaise.
3. Gels: a gel is a colloidal system in which the dispersed
phase and the solid forms the continuous phase. A gel does not flow. Some of
the liquid is adsorbed on the surface of the solid molecule and is called bound
water which is responsible for the gel structure.
phase and the solid forms the continuous phase. A gel does not flow. Some of
the liquid is adsorbed on the surface of the solid molecule and is called bound
water which is responsible for the gel structure.
4. Sol: in this system, solids of colloidal dimensions are
dispersed throughout a liquid. Solid forms the dispersed phase and liquids
solid forms the dispersed phase and liquids the continuous phase. The visiosity
of sols may range from liquid, e.g. skim milk to extremely viscous e.g. tomato
which barely flow.
dispersed throughout a liquid. Solid forms the dispersed phase and liquids
solid forms the dispersed phase and liquids the continuous phase. The visiosity
of sols may range from liquid, e.g. skim milk to extremely viscous e.g. tomato
which barely flow.
