Eggs and Egg Cookery Chapter 24. Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ 07458. All.

Eggs and Egg Cookery

Chapter 24

Introductory Foods, 13th ed.Bennion and Scheule

© 2010 Pearson Higher Education,Upper Saddle River, NJ 07458. • All Rights Reserved.2

Use of Eggs Emulsions (Lecithin in yolk) Foam Coagulation Clarifying agent Color Flavor



Composition Whole Eggs

75% water 12% protein 10% fat 1% carbohydrate 1% minerals

Egg White 88% water 4g protein 0g fat Trace minerals

Egg Yolk 49% water 3g protein 5g fat



Nutritive Value Protein

High protein efficiency ratio (PER)

Whites Ovalabumin

Yolks Lipoproteins

Lipids Triglycerides Phospholipids Cholesterol

Pigments Xanthophyll Vitamin A



Shell

Thick White

Yolk

Thin white

Air cell

Chalazae

Vitelline Membrane

Basic parts of the egg



Structure Egg Shell

Porous Allows exchange of gas and moisture

Shell color has no impact (flavor or nutrition)

Protective coating Cuticle or Bloom Replaced with oil after washing

Air Cells Become larger as egg ages



Structure

Albumen Egg white Consists of thick and thin portions

Chalazae Thickened “rope-like” white that anchors yolk

Membranes Thin membrane that surrounds yolk Shell membranes



Structure

Yolk Composed of protein granules and oil droplets

within spheres

Germinal disc No difference between fertile and infertile eggs

Blood spots Because of blood vessel rupture on surface of yolk



Egg Quality

Fresh eggs Stand high when broken

onto a plate Yolk stands high and round Two “layers” of egg white

evident Small air cells Yolks are slightly acidic

Older egg Spreads out when broken

onto a plate Yolk does not stand high

and round One “layer” of white that

spreads out Large air cells Egg becomes more alkaline



Egg Flavor and Odor Affected by

Feed Hen Storage



Purchasing & Quality Purchasing

Pack date USDA grading

U.S. Grade AA, Grade A, or Grade B

Quality measurement Candling

Sizing Recipes standardized for large eggs Consider cost of eggs per dozen



Food Safety 1 out of 20,000 eggs contaminated with Salmonella

enteritidis

About 2.3 million eggs contaminated

Unbroken eggs may be contaminated

Raw or undercooked eggs implicated in about 80 percent of foodborne illness outbreaks



Regulation & Processing Safe food handling instructions must be on

cartoons

Eggs must be held and displayed at or below 45°F (7°C)

Some eggs may be Pasteurized Irradiated



Recommendations Avoid cross-contamination with raw eggs

Do not eat raw eggs

Cook over moderate heat

Use pasteurized eggs for high-risk populations



Preservation and Processing Processed egg products

Frozen Yolks frozen with salt or sugar for stabilization

Dried Liquid Other

Pasteurization required of all processed eggs



Egg Substitutes Provide a low-cholesterol egg product

Contain No or very little yolk High concentration of egg white

Additional ingredients may include Corn or soybean oil Nonfat dry milk Soy protein isolate Egg white solids Calcium caseinate



Heat Coagulation Heat denatures egg proteins

Proteins aggregate into a three dimensional gel network

Network stabilized by cross bonds Disulfide bonds Hydrogen bonds

Coagulation proceeds gradually



Heat Coagulation

Egg yolks vs. egg whites

Diluted eggs (i.e. diluted with milk)

High temperatures Promote toughness and shrinking

Rapid heating

Influence of the addition of Sugar, Salt, Acid



Coagulation by Beating

Beating causes part of the proteins to become coagulated

Egg whites Become foamy, then form soft and stiff peaks Over beaten – then dry and flocculated

Whole eggs Will beat stiffer

Egg yolks Increase slightly in volume



Egg White Foams Thin whites – more fluffy, less body Thick whites – more stable foam Room temperature – greater volume Fine beater wires – finer air cells Bowl type



Egg White Foams

Impact of added substances Fat

interferes

Salt decrease volume and stability

Acid (Cream of Tartar) increases stability Increases whipping time

Sugar increases beating time Increases stability



Egg Preparation Methods Poached Cooked in shell Fried eggs Scrambled eggs Shirred eggs Omelets

French Puffy

Crêpes Soufflés Custard

Baked Soft or Stirred

Meringues Microwave cooking



Why do eggs turn green!

Overcooking

Held hot – too long

Older (more alkaline eggs) are more susceptible

Green color caused by Reaction of iron in yolk with hydrogen sulfide

in white to produce ferrous sulfide

Eggs and Egg Cookery Chapter 24. Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ 07458. All.

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