Eggs!

Chapter 16

Draw and label the parts of the egg in your notes. Air Cell

Shell

Membrane

Yolk

White

Chalazae

Nutritional Value

• One of the best sources of complete proteins

• Many vitamins and minerals

• Yolks are high in cholesterol

• Egg whites are cholesterol free

Egg Grades

• For retail sell they must be graded.

• 4 factors determine grade– Condition of the shell– Size of air cell– Clearness and thickness of white– Condition of yolk

Egg Grades

• Graded for quality by a system called candling. (looking for the 4 factors)– Eggs move along rollers over bright lights.– Lights illuminate the eggs’ structure.– Skilled people can then look at the eggs

carefully and remove any that do not meet standards.

– Called candling because candles were used originally - no electricity.

Egg Grades

• 2 main grades available in supermarkets• Look for grades listed on egg cartons• Grade AA

– Clean, unbroken shell with small air cell, when egg is broken yolk stands tall, white is thick, clear and covers a small area.

• Grade A– Clean, unbroken shell with slightly larger air

cell, when broken white covers a larger area.

Egg Size and Color

• Eggs are sized on the basis of a medium weight per dozen.

• Extra large, large and medium eggs are the most common sizes sold.

• Most recipes use medium or large eggs• Extra large cost the most, medium the least.• Size has no relation to quality• Breed of chicken determines egg color. • Shell color does not affect quality, flavor or

nutritional value.

Storing Eggs

• Buy eggs only from refrigerated cases if at a store!

• Check to make sure no eggs are dirty or broken before buying.

• Cracked eggs may contain dangerous bacteria.• Eggs should go immediately in the refrigerator • Store fresh eggs may remain in the refrigerator

for 4-5 weeks.

Storing Eggs

• Some recipes call only for egg yolks or egg whites

• To store leftover yolks cover them with cold water and refrigerate in a tightly covered container

• To store egg whites, refrigerate them in a tightly covered container.

• Use yolks within one or two days• Use whites within four days.

Eggs as Ingredients! : Emulsifiers

• An emulsion is the mixture that forms when you combine liquids that ordinarily do not mix. (oil, vinegar, water and water based liquids)

• Temporary – Shake them and ingredients combine, leave alone

and they separate (Italian Dressing)

• Permanent– Will not separate because an emulsifying agent has

been added – most commonly egg yolks (Mayonnaise)

Eggs as Ingredients! : Foams

• Used to add air to foods (Angel food cake)• Factors that affect foams

– Temperature, beating time, fat, acid and sugar.• Temperature

– Eggs separate best when cold– Egg whites reach max. volume when at room

temperature.• Beating time

– Under beating causes them to fall after a short time because they won’t hold their shape.

– Over beating makes the foam break down into curds.

Eggs as Ingredients!: Foams

• Fat– Inhibit the formation of foam.– Very important to not have ANY yolk in bowl (yolks

contain fat …cholesterol specifically)– Clean beaters – dirty beaters may have fat on them

(think butter from cookies)

• Acid– Makes foams more stable (cream of tartar)

• Sugar– Increases stability and beating time also.

Eggs as Ingredients!: Foams

• 3 stages: Foamy, soft peak, hard peak• Foamy

– Transparent, bubbles and foam on surface, will run out of bowl if you try to pour it.

• Soft Peak– White and shiny, when you lift the beater foam stands

in peaks that bend at the tips

• Hard Peak– White and shiny, when you lift the beater foam stands

in strait peaks.

Eggs as Ingredients!: Thickeners

• Heat causes egg proteins to coagulate (thicken)

• When adding eggs to a hot mixture to thicken you need to first add a small amount of the hot to the beaten eggs, stir then add warmed egg mixture to the hot.

• This keeps eggs from curdling or cooking into lumps.

Eggs as Ingredients!: Binding and Interfering Agents, Structure

• Binding– Hold things together like and meatloaf.

• Interfering– Inhibit the formation of ice crystals in frozen

foods like custard and ice cream.

• Structure– Add structure to baked products like cookies

and cake

Food Science Principles

• Eggs coagulate when heated during cooking.

• Egg white coagulates at a slightly lower temperature than the yolk. –below boiling for both.

• Use low to moderate temps for cooking so eggs do not dry out or get tough.

Methods of Cooking

• Safely cooked eggs have completely set whites and thickened yolks.

• Yolks do not need to be hard but should not be runny.

• Dishes with eggs like breakfast casseroles, quiches, soufflés should reach 160

• When cooking eggs in a skillet pre-heat the skillet and any fat you may be using.

Homework

• On a piece of notebook paper simplify the directions in the book for each of the following: – Due tomorrow (pg 308-9)

• Microwaving eggs• Omelets• Soufflés• Meringues• Custards