Eggs and Egg Cookery Chapter 24

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 2 Use of Eggs Emulsions (Lecithin in yolk) Foam Coagulation Clarifying agent Color Flavor

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 3 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 4 Nutritive Value Protein High protein efficiency ratio (PER) Whites Ovalabumin Yolks Lipoproteins Lipids Triglycerides Phospholipids Cholesterol Pigments Xanthophyll Vitamin A

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 5 Shell Thick White Yolk Thin white Air cell Chalazae Vitelline Membrane Basic parts of the egg

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 6 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 7 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 8 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 9 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 10 Egg Flavor and Odor Affected by Feed Hen Storage

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 11 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 12 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 13 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 14 Recommendations Avoid cross-contamination with raw eggs Do not eat raw eggs Cook over moderate heat Use pasteurized eggs for high-risk populations

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 15 Preservation and Processing Processed egg products Frozen Yolks frozen with salt or sugar for stabilization Dried Liquid Other Pasteurization required of all processed eggs

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 16 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 17 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 18 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 19 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 20 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 21 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 22 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

Introductory Foods, 13 th ed. Bennion and Scheule © 2010 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved. 23 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