1. PHYSICAL STATE OF INGREDIENTS IN FOOD SYSTEMS
Food Dispersions
1. True solution
2. Colloidal dispersion
3. Emulsion
4. Foam
5. Gel
Dispersions
1. Continuous phase
2. Dispersed phase
May be solid, liquid, or gas.

2. Colloidal Dispersion (SOL)
True Solution
The dispersion of particle < 1 nm in liquid.
Examples: sugar, lactose, minerals, and vitamins.
Colloidal Dispersion (SOL)
Dispersion of particle sizes between nm in liquid.
Common colloids: dispersion of proteins, large molecular salts.
Example: milk.

3. Emulsions
Liquid/liquid systems of 2 immiscible substances are called emulsion. Substances or particle size = microns.
Examples: butter (w/o), margarine (w/o), mayonnaise (o/w), salad dressing (o/w), milk (o/w), cream (o/w), and chip-dip (o/w).
Oil
Oil
Oil
H O
H O 2
Oil 2
Oil
Oil
Oil
H O
H O 2
Oil 2
Oil
Oil
Water
Oil
Oil/Water
Water/Oil

4. DESTABILIZATION OF THE DISPERSION
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Water
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Aggregation
Water
Oil
Oil separation
from water
Water

5. EMULSIFIER Mayonnaise Emulsifier Margarine Water Oil Hydrophilic group
Hydrophobic
group
Oil
Water

6. CHEMICAL STRUCTURE OF EMULSIFIERS
Phospholipids (Lecithin) O CH 2
O C (CH 2 ) 16 CH 3 O CH O
CH O C (CH 3 2 ) 14 CH 3 CH + 3
N CH 2 CH 2
O P O CH 2
Hydrophobic CH O 3 - (
fat-soluble)
Hydrophilic (water-soluble)
Mono-
Glycerides (mono-
stearate) O CH 2
O C (CH 2 ) 16 CH 3
HO CH
Hydrophobic
HO CH 2
Hydrophilic
Di-glycerides (
di-stearate) O CH 2
O C (CH 2 ) 16 CH 3 O
CH O C (CH 2 ) 16 CH 3
HO CH 2
Hydrophobic
Hydrophilic

7. Span 60 (sorbitan mono-stearate)
C CH CH 2
O C (CH ) 16 CH 3
C CH C H OH HO
O CH
Hydrophobic
Hydrophilic
Tween 60 (polyoxyalkylene sorbitan mono-stearate)
Hydrophobic
Hydrophilic

8. SOME DESIRABLE CHARACTERISTICS OF FOOD EMULSIFIERS
Ability to reduce interfacial tension below 10 dynes/cm
Ability to be rapidly absorbed at the interface
Ability to function effectively at low concentrations
Resistance to chemical change
Lack of odor, color, and toxicity
Economical

9. FOAM Gas is dispersed in liquid or semi-liquid.
Dispersed-phase: gas
Continuous-phase: liquid
It requires a 3rd component possessing protective or stabilizing properties to maintain the dispersion.
Example: whipped topping

10. The important foam stability factors are:
1. Surface tension
2. Concentration of separate phase
3. Presence of foaming agent to lower surface tension
4. Viscosity of liquid - the higher the viscosity, the more stable the foam.
5. Presence and thickness of adsorption layer (a 3rd stabilizing material).

11. GEL semi-solid state with 2 continuous phases.
Continuous phase of interconnected particles and/or macro-molecules intermingled with a continuous phase of liquid phase such as water.
Examples: jello, jam

12. FOOD DISPERSIONS Dispersed Continuous Name of Examples
Phase Phase Dispersion
Solid (S) Liquid (L) Solution, Colloidal dispersion Milk
Liquid (L) Liquid (L) Emulsion French dressing
Gas (G) Liquid (L) Foam Whipped topping
Gas (G) Solid (S) Solid Foam Foam candy
Solid (S) Gas (G) Solid Aerosol Smoke for flavoring food

13. STABILITY OF A FOOD DISPERSION
1. Dispersed particle size
2. Viscosity of continuous phase
3. Dispersed phase concentration
4. Density difference between 2 phases