Eggs as a Functional Emulsifier Shelly Mc Kee

Eggs as a Functional Emulsifier Shelly Mc. Kee, 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) l Minerals: iron, phosphorus, calcium, manganese, iodine, copper and zinc l Vitamins A and D, B 12, E, biotin, choline, folic acid, inositol, pantothenic acid, pyridoxine and thiamin Egg Yolk Composition l Xanthophyll: 33% main yellow 50% pigment l 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. l Egg yolks can be used to fortify whole egg blends to increase emulsifying action l 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 l Hollandaise sauce l Salad dressings l Baked goods l • Mechanisms l 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 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: 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!