Eggs as a Functional Emulsifier

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Eggs as a Functional Emulsifier

• Shelly McKee, Auburn University
• American Egg Board

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Egg Industry Structure
Producers
Shell Egg Grading
Further Processors
Bakery Supply
Food Manufacturers
Food Brokers
End Users
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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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Egg Structure
Shell
Air Cell
Shell Membranes
Yolk
Chalazae
Latebra
Chalaziferous Layer
Germinal Disc
Thin Albumen (White)
Vitelline (Yolk) Membrane
Thick Albumen (White)
Chalazae
Natures Most Perfect Food The Egg!
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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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Egg Yolk Composition


65.5
Triglycerides (Neutral Fats) Oleic Palmitic
Linoleic Stearic Other
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28.3
Phospholipids
Lecithin (phosphatidylcholine) 73 Cephalin
(phosphatidylethanolamine) 15 lysophosphatidlyc
holine 5.8 sphingomyelin 2.5 lysophosphatidyl
ethanolamine 2.1 plasmalogen 0.9 inositol
phospholipid 0.6



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Emulsification

• The phospholipids, lipoproteins and proteins
  foundin 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 wholeegg blends
  to increase emulsifying action
• No essential differences are found inemulsifying
  properties of dried wholeegg and yolk and fresh
  liquid eggs

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

• Applications
• Mayonnaise
• Hollandaise sauce
• Salad dressings
• Baked goods

• Mechanisms
• Egg emulsifying properties come from the yolk

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Emulsifiers in the egg yolk

• Phospholipids-lecithin
• Lipoproteins
• Proteins- having hydrophilic and
• hydrophobic regions

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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
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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

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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

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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.
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Long shelf life (1 year), functionality,variety
blends
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FROZEN EGG PRODUCTS

• Frozen yolk has 10 salt or sugar added to
  prevent irreversible protein gelation. Result is
  a smooth creamy, viscous yolk.

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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.

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Mayonnaise
Made with liquid frozen whole egg
Made with liquid frozen salted egg yolk
Cheese Cake
Cinnamon rolls
Made with liquid frozen sugared egg yolk
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Some common applications of emulsifiers

• BreadIt 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.
• ChocolateAll 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.

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Some common applications of emulsifiers

• Ice-creamIce-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.