Eggs! Chapter 16. Draw and label the parts of the egg in your notes. Air Cell Shell Membrane Yolk...

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