1. Eggs as a Functional Emulsifier
Shelly McKee, Auburn University
American Egg Board

2. Egg Industry Structure
Producers
Shell Egg Grading
Further Processors
Food Manufacturers
Bakery Supply
Food Brokers
End Users
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3. Egg Products Processing Overview
HOLDING
Refrigerated
no longer than
7 to 10 days
BREAKING
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
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4. Nature’s Most Perfect Food – The Egg!
Egg Structure
Shell
Air Cell
Shell Membranes
Yolk
Chalazae
Latebra
Chalaziferous Layer
Germinal Disc
Thin Albumen (White)
Vitelline (Yolk)
Membrane
Thick Albumen (White)
Chalazae
Nature’s Most Perfect Food – The Egg!
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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
Xanthophyll: main yellow pigment
Egg Yolk Composition
33%
50%
17%
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6. Egg Yolk Composition Triglycerides (Neutral Fats) 65.5% 50% 27% 11% 6%
Oleic
Palmitic
Linoleic
Stearic
Other
65.5%
50% 6%
27%
11%
28.3%
Phospholipids
Lecithin (phosphatidylcholine) 73%
Cephalin (phosphatidylethanolamine) 15%
lysophosphatidlycholine 5.8%
sphingomyelin 2.5%
lysophosphatidylethanolamine 2.1%
plasmalogen 0.9%
inositol phospholipid 0.6%

7. 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
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8. Emulsions/Surface activity-
a stable mixture of two immiscible liquid phases, one which is dispersed in the other
Mayonnaise

9. Emulsification Applications Mechanisms Mayonnaise Hollandaise sauce
Salad dressings
Baked goods
Mechanisms
Egg emulsifying properties come from the yolk

10. Emulsifiers in the egg yolk
Phospholipids-lecithin
Lipoproteins
Proteins- having hydrophilic and
hydrophobic regions

11. 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

12. 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

13. 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

14. 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.

15. Long shelf life (1 year), functionality, variety blends

16. FROZEN EGG PRODUCTS
Frozen yolk has 10 % salt or sugar added to prevent irreversible protein gelation. Result is a smooth creamy, viscous yolk.

17. 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.

18. Mayonnaise Cheese Cake Cinnamon rolls
Made with liquid frozen whole egg
Made with liquid frozen salted egg yolk
Cheese Cake
Cinnamon rolls
Made with liquid frozen sugared egg yolk

19. 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.

20. 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 ice-cream 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.