Oil and Water Dont Mix

1
Oil and Water Dont Mix

• Water is polar and oil is non-polar and so have
  no affinity for each other but within either one,
  the molecules have a great affinity for
  themselves. This affinity causes Surface Tension
  which ensures that a fluid, e.g., water, in a
  container forms a surface between it and another
  fluid such as oil or air.

2
Coalescence of Oil Droplets (surface tension
reduction)
Water
oil
oil
oil
oil
oil
oil
3
Oil and Water Separation
Water
4
Emulsion

• A dispersion of one (or more) phase(s) such as
  oil, water or air in another phase in which it is
  normally immiscible
• They are often liquid but can also be solid
  (e.g., salami, pepperoni)

5
Emulsion

• Emulsions consist of at least two parts
• The main phase in which the other is dispersed.
  This phase is called the Continuous, Coherent,
  Outer or Closed Phase.
• The other phase is called the Disperse,
  Discontinuous, Inner or Open Phase.
• Common in food systems and include foods like
  mayonnaise and margarine

6
Types of Emulsions

• Water-in-oil
• margarine, low-fat spreads, butter
• Oil-in-water-
• mayonnaise, salad creams, salami, sausage
• Air and oil-in-water
• ice cream, whipped cream

7
Phases of an Emulsion
Continuous phase
Water
8
Droplet Size and Emulsion Property

• Normal droplets 0.01-100 mM
• Macroemulsion droplets 0.5-100 mM
• Microemulsion 0.01 - 0.5 mM

The size of the droplets depends on the method of
dispersion and time Emulsions with small
droplets have high viscosity Emulsions with
large droplets have low viscosity
9
Phase Separation Prevention
Water
10
Emulsifiers

• Emulsifiers have the following molecular features

Polar head, likes water
Non-polar tail, likes oil
11
Types of Emulsifiers

• Cationic
• Anionic
• Amphoteric
• Non-ionic

12
Emulsions (Oil in water, O/W)
Water
13
Emulsions (Oil in water, O/W)

• Water interacts with the polar emulsifier heads
• The oil droplets interact with the nonpolar
  emulsifier tails
• There is no driving force for separation of the
  phases

14
Hydrophile-Lipophile Balance(solubility in polar
and non-polar solvents)
HLB scale ranges from 1(most lipophilic to 20
(most hydrophilic)

• Water-in-oil emulsifiers
• HLB values of 3-6
• Humectants
• HLB values of 7-9
• Oil-in-water emulsifiers
• HLB values of 8-18
• Stabilizers of turbid systems
• HLB values of 15-18

15
HLB Value Calculation

• HLB 20 (1 S/A)
• S saponification number of ester
• A acid number of acid
• Blending Emulsifiers
• A 100 (X HLBB)/HLBA - HLBB

16
Common Emulsifiers

• HLB Value
• Potassium oleate 20
• Polyoxyethylene sorbitan monooleate 15
• Gelatin 9.8
• Mono and diglycerides (65 mono) 3.5
• Mono and diglycerides (50 mono) 2.8
• Oleic acid 1.0

17
Emulsion Stabilizers

• Emulsions are commonly stabilized by the addition
  of carbohydrate polymers
• agar (ice cream)
• alginic acid (ice cream)
• guar gum (cheese foods)
• locust bean gum (salad dressing)
• xanthan gum (salad dressing)
• carboxymethyl cellulose (ice cream)