PHYSICAL STATE OF INGREDIENTS IN FOOD SYSTEMS

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PHYSICAL STATE OF INGREDIENTS IN FOOD SYSTEMS
Food Dispersions 1. True solution 2. Colloidal
dispersion 3. Emulsion 4. Foam 5. Gel   Dispersion
s 1. Continuous phase 2. Dispersed phase May be
solid, liquid, or gas.
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True Solution The dispersion of particle lt 1 nm
in liquid. Examples sugar, lactose, minerals,
and vitamins.   Colloidal Dispersion
(SOL) Dispersion of particle sizes between 10-100
nm in liquid. Common colloids dispersion of
proteins, large molecular salts.   Example
milk.
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Emulsions Liquid/liquid systems of 2 immiscible
substances are called emulsion. Substances or
particle size 10-100 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
2
Oil
Oil
Oil
Oil
H O
H O
2
2
Oil
Oil
Oil
Oil
Water
Water/Oil
Oil/Water
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DESTABILIZATION OF THE DISPERSION
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Water
Oil
Oil
Oil
Oil
Oil
Oil
Aggregation
Oil
Oil
Oil
Oil
Water
Oil separation
Oil
from water
Water
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EMULSIFIER
Mayonnaise
Water
Oil
Emulsifier
Hydrophilic
group
Margarine
group
Hydrophobic
Oil
Water
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CHEMICAL STRUCTURE OF EMULSIFIERS
Phospholipids (Lecithin)
O
CH

O C (CH
)
CH
2
2
16
3
O
CH O C (CH
)
CH
CH
2
14
3
O
3

CH
N CH
CH

O P O CH
Hydrophobic
3
2
2
2
O
CH
-
3
fat-soluble)
(
Hydrophilic (water-soluble)
Glycerides (mono-
stearate)
Mono-
O
CH

O C (CH
)
CH
2
2
16
3
HO CH
Hydrophobic
HO CH
2
Hydrophilic
Di-glycerides (
di-stearate)
O
CH

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

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FOAM
Gas is dispersed in liquid or semi-liquid. Dispers
ed-phase gas Continuous-phase liquid   It
requires a 3rd component possessing protective or
stabilizing properties to maintain the
dispersion. Example whipped topping
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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).
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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
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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
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STABILITY OF A FOOD DISPERSION
1. Dispersed particle size 2. Viscosity of
continuous phase 3. Dispersed phase
concentration 4. Density difference between 2
phases