10 egg cookery

8/12/2019 10 Egg Cookery

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EGG STRUCTURE

Egg white/ Albumen

consists of thick and thin portions

thick white has 4x ovomucin compared to thin

white

high water content (~90%) and minimal fat

consists of proteins (ovalbumin, conalbumin,

ovomucin, lysozyme, avidin)

B- vitamins

EGG STRUCTURE

Egg yolk

Nutrientdense

Lipids: triglycerides, lecithin, cholesterol

Proteins: Livetin, Lipovitellin, Phosvitin

Fat-soluble vitamins

Minerals : Fe, P, Zn

Contains pigments

Color depends on feed

Composition:

Yolk and white are not equal

( de Leon, 2006)

%

Egg

%

water

%

protein

%

fat

%

ash

Whole

egg

100 65.5 11.8 11 11.7

Albumen 58.0 88.0 11.0 0.2 0.8

Yolk 31.0 48.0 17.5 32.5 2.0

Classification of eggs according to size

(PNS/BAFPS 2005)

Weight Class Weight Range (in grams/egg)

Jumbo 70 and above

Extra Large 6570

Large 6065

Medium 5560

Small 5055

Pullets 45

40Pewee 4045

No weight < 40

Deteriorative changes in eggs

Loss of CO2

Increase in alkalinity (7.9-9.3 in the first 3 d) ofegg white, leads to thinning

Yolk not held in place

Entrance of water into the yolk

Vitelline membrane weakens

Flattening of the yolk

Enlargement of air cell

http://caperberry.blogspot.com/2009/04/egg-freshness-guide.html

Deteriorative changes in eggs

Day 1 Day 7 Day 14


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Test for egg quality

Indirect Method

Candling Sink or swim test

Candling Method

http://www.colorado.gov

Sink or Swim Test

http://caperberry.blogspot.com/2009/04/egg-freshness-guide.html

Day 1 Day 7 Day 14

Test for egg quality

Direct Methods

Haugh unit (ht of thick

white in rel. to egg wt)

Yolk index (yolk height in

relation to its width)

Eye scoring (yolk color

chart)

http://www.braininajamjar.co.uk; http://www.baxlo.com/Haugh-Tester.html

Germ spot

YolkShell

Thin white

Thick white

Inner

membrane

Outer

membraneChalazae

Air cell

Cuticle

Avidin,

Lysozyme, etc.

NO antimicrobial agents in

yolk!!!

Egg Safety

(Slide from Dr. AAGabriel FN 11 lecture)
http://www.braininajamjar.co.uk/http://www.baxlo.com/Haugh-Tester.htmlhttp://www.baxlo.com/Haugh-Tester.htmlhttp://www.baxlo.com/Haugh-Tester.htmlhttp://www.baxlo.com/Haugh-Tester.htmlhttp://www.braininajamjar.co.uk/http://www.braininajamjar.co.uk/


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Transovarian infection of

eggs by Salmonella

Egg Safety

(Slide from Dr. AAGabriel FN 11 lecture)

Egg Safety Tips

Buy and store appropriately

Eggs are clean and no crack

Refrigerate promptly

Store eggs in their original carton and use

them within 3 weeks

Egg Safety Tips

Cook thoroughly

Cook until both white and yolk are firm

Casseroles and dishes containing eggs should

be cooked to 160F (72 C)

Bennion (1985), Eades (2006)

Cold storage (4-7 C: 6 months, 25-32 C, 1 week)

Closed container storage

Submerging in water glass, Na silicate (4-6 months)

Mineral oil coating

Freezing(yolk must be pre-treated with

salt/sugar/corn syrup)

Drying (Dry mixes)

Salting(curing for 2 weeks) Pickling

Preservation of eggs

Eggs in food preparation

Heat coagulation of egg proteins.Unfolding and then aggregation into a 3D gel

network, resulting in thickening.

60 C, White: transparent, viscous sol

opaque white gel

65 C, Yolkmealy


Uses of eggs in food preparation

Main protein dish

Garnish (Arroz caldo, palabok, etc.)

Structure-enhancer (Cakes, quick breads, yeast

breads, etc.)

Thickening agent (Soft pie fillings, cooked salad

dressings, etc.)

Gelling agent (Custards, etc.)



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Uses of eggs in food preparation

Binding and coating (Meat loaf, meat balls, etc.)

Leavening agent (Cakes, etc.)

Emulsifying agent (Mayonnaises, dressings, cream puffs,

etc.)

Clarifying agent (Hot broths, coffee, wine, etc.)


Basic methods of cooking eggs

Served in shell

Hard boiled (15-17 min)

Excessive heatingFeS liberation in yolk

Poaching

Requires high quality eggs

Frying(sunny side up, over easy)

Scrambled

Custard


EGG: Leavening Property

Low surface tension: OVOMUCIN

Low vapor pressure: i.e. not volatile

Tendency for substance to solidify at the

surface

LEAVENING PROPERTY OF EGGS

PROPERTY OF EGG WHITE FOAMS

1. Volume: increases 6-8 x its originalvolume

2. Stiffness: protein denaturation

3. Texture: foam with fine air cells

4. Stability: egg whites retain its shape

after mixing

Determinants of formation and

stability of egg white foams

1. Starting ingredients2. Degree of beating

3. Temperature

4. Mixing bowl and utensils

5. Sugar

6. Fluid

7. Salt


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1.Starting Ingredients

Fresh eggs whites that

are not contaminated

with egg yolk or any

form of fat.

2.Degree of beating

Too much (dry, less stable

and brittle)

too little (liquid not

thoroughly distributed)

beating will form unstable

foams that will separate

upon standing

3.Temperature

Everything should be

at room temperature

(bowl, beater and

eggs!)

4.Mixing Bowl and Utensils

Deep bowls with

rounded bottom and

sloping sides

Utensils: wire whisk,

hand mixer or rotary

egg beater

5.Sugar

Sugar should be added near the end ofbeating/ whipping

Contributes to stability

Prevents over beating and creates a

smooth and satiny surface

6.Fluid

Increases volume but decreasesstability

Decreases stability of egg white

foams

7.Salt


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8. Acid

Egg whites whip more easily when its pH is

lowered

Vinegar, lemon juice or cream of tartar

1 tsp cream of tartar/ cup of egg white

1/8 tsp lime juice/egg white

Changes in Egg White During Beating

1. Formation andsubdivision of air

bubbles2. Color changes

3. Increase in stiffness

4. Increase in volume

5. Decrease inelasticity

6. Surface changes:loses its shine

SLIGHTLY BEATEN/FOAMY

Frothy,transparent withlarge air bubbles

Flows easilyfrom the bowl

Use: coating,and clarifying

SOFT PEAK STAGE

Foamy with smaller airbubbles, opaque, shiny,moist

Flows if bowl is tipped,separates on standing

Use: soft meringues,sponge cakes, souffls,foamy omelets

STIFF PEAK

Stiff, shiny, still moist,verytiny bubbles, may slip

Use: soft/hard meringues,

most cakes, ice creams,

sherbets, marshmallows,

cooked frostings

BRITTLE FOAM/DRY

White, dry, flakes off,with solid white specks

Liquid portion easilyseparates on standing


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METHODS OF TESTING FOAM

STIFFNESS

1. Appearance: size of air

bubbles and color

2. Degree of stiffness of

peaks

3. Rate of flow: The inverted

bowl test

10 egg cookery

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