Eggs as a Functional
Emulsifier
Shelly McKee, Auburn University
American Egg Board
Nature’s Most Perfect Food – The Egg!
Egg Industry Structure
Producers
Shell Egg Grading
Further Processors
Food Manufacturers
Bakery Supply
Food Brokers
End Users
Nature’s Most Perfect Food – The Egg!
1.2
Egg Products Processing
Overview
HOLDING
BREAKING
Refrigerated
no longer than
7 to 10 days
and separating yolks,
whites, shells
– Filtered
– Mixed
– Chilled
PASTEURIZATION
PACKAGING
REFRIGERATED
LIQUID EGG
PRODUCTS
FROZEN EGG
PRODUCTS
The design and construction of
EGG PROCESSING EQUIPMENT
meets E-3-A or 3-A Sanitary Standards
DRIED EGG
PRODUCTS
Nature’s Most Perfect Food – The Egg!
1.3
Egg Structure
Shell
Yolk
Air Cell
Shell Membranes
Chalazae
Latebra
Chalaziferous Layer
Germinal Disc
Thin Albumen (White)
Vitelline (Yolk)
Membrane
Thick Albumen (White)
Chalazae
Nature’s Most Perfect Food – The Egg!
1.5
Egg Yolk Composition

Approximately 50% water, 17% protein (mainly
ovovitellin), 33% lipids (mainly triglycerides,
lecithin [phospholipids] and cholesterol)
 Minerals: iron, phosphorus, calcium,
manganese, iodine, copper and zinc
 Vitamins A and D, B12, E, biotin, choline, folic
acid, inositol, pantothenic acid, pyridoxine and
thiamin
Egg Yolk Composition
 Xanthophyll:
33%
main yellow
50%
pigment
Water
Protein
Lipids
17%
Nature’s Most Perfect Food – The Egg!
2.4
Egg Yolk Composition
Triglycerides (Neutral Fats)
Oleic
Palmitic
Linoleic
Stearic
Other
Phospholipids
65.5%
50%
27%
11%
6%
6%
28.3%
Lecithin (phosphatidylcholine)
73%
Cephalin (phosphatidylethanolamine) 15%
lysophosphatidlycholine 5.8%
sphingomyelin 2.5%
lysophosphatidylethanolamine 2.1%
plasmalogen 0.9%
inositol phospholipid 0.6%
Nature’s Most Perfect Food – The Egg!
Emulsification
The phospholipids, lipoproteins and proteins found
in egg yolks are surface active agents that enable
the formation of emulsions from immiscible liquids
such as oil and water.

Egg yolks can be used to fortify whole
egg blends to increase emulsifying action

No essential differences are found in
emulsifying properties of dried whole
egg and yolk and fresh liquid eggs
Nature’s Most Perfect Food – The Egg!
4.6
Emulsions/Surface activitya stable mixture of two immiscible liquid phases, one
which is dispersed in the other
Mayonnaise
Nature’s Most Perfect Food – The Egg!
Emulsification
• Applications




Mayonnaise
Hollandaise sauce
Salad dressings
Baked goods
• Mechanisms

Egg emulsifying
properties come from
the yolk
Nature’s Most Perfect Food – The Egg!
Emulsifiers in the egg yolk
•Phospholipids-lecithin
•Lipoproteins
•Proteins- having hydrophilic and
hydrophobic regions
Nature’s Most Perfect Food – The Egg!
Emulsions/Surface activity
3 Components necessary for an
oil-in-water emulsion
a) oil
b) water
c) interface, proteins,
phospholipids, lipoproteins
Water
Oil
Proteins, phospholipids,
lipoproteins
Nature’s Most Perfect Food – The Egg!
Good Stable Emulsion
• Should be viscous to hold suspended
ingredients in place
• Droplets dispersed (oil or water) should
be small enough to remain in
suspension and should be evenly
distributed throughout the matrix
Nature’s Most Perfect Food – The Egg!
Emulsions
Factors affecting emulsions
•Viscosity (Stability over time)
•Amount of emulsifier (Formation and Stability)
ratio of emulsifier/fat/water
•Additives
0.05% sodium-2-lactylate
increases emulsion stability
Nature’s Most Perfect Food – The Egg!
Mayonnaise is made by combining
lemon juice or vinegar with egg yolks.
Eggs (containing the emulsifier lecithin)
bind the ingredients together and prevent
separation.
Adding oil too quickly (or insufficient, rapid
whisking) will keep the two liquids from
combining (emulsifying).
As the sauce begins to thicken, oil can be
added more rapidly. Seasonings are
whisked in after all of the oil has been
added.
Nature’s Most Perfect Food – The Egg!
Long shelf life (1 year), functionality,
variety blends
Nature’s Most Perfect Food – The Egg!
FROZEN EGG PRODUCTS
• Frozen yolk has 10 %
salt or sugar added to
prevent irreversible
protein gelation.
Result is a smooth
creamy, viscous yolk.
Nature’s Most Perfect Food – The Egg!
Egg Products
• Sanovo Foods produces enzyme-modified
product Heat-stable egg yolk.
• Uses enzymes to degrade phospholipids
phospholipids which account for 7-8% of the
egg yolk. The enzyme converts a large part
of the lecithin in the egg yolk into lysolecithin,
which has much better emulsifying
properties.
Nature’s Most Perfect Food – The Egg!
Made with liquid frozen whole egg
Made with liquid frozen salted egg yolk
Made with liquid frozen sugared egg yolk
Nature’s Most Perfect Food – The Egg!
Some common applications of
emulsifiers
• Bread
It is possible to make bread without emulsifiers but
the result is often dry, low in volume and easily
stales. As little as 0.5% emulsifier added to the
dough is enough to achieve an enhanced volume, a
softer crumb structure and a longer shelf-life.
• Chocolate
All chocolate products contain 0.5% of lecithin.
These emulsifiers are added to provide the right
consistency of the chocolate, so it can be molded
into plates of chocolate, chocolate bars etc.
Nature’s Most Perfect Food – The Egg!
Some common applications of
emulsifiers
• Ice-cream
Ice-cream: both a foam and an emulsion it contains
ice crystals and an unfrozen aqueous mix.
• Emulsifiers are added during the freezing process, to
promote a smoother texture and ensure the icecream does not melt rapidly after serving.
• They also improve freeze-thaw stability. All this
applies to other desserts such as sorbet, milkshake,
frozen mousse and frozen yogurt as well.
Nature’s Most Perfect Food – The Egg!