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EGGS!EGGS!

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What we’re doing today What we’re doing today folks!folks!

HistoryHistory EtiologyEtiology HealthHealth Dissecting the eggDissecting the egg Good Egg, Bad Good Egg, Bad

EggEgg Cooking Cooking

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Background HistoryBackground History 300 mya- eggs laying in the ocean300 mya- eggs laying in the ocean

100 mya- mineralized egg shell100 mya- mineralized egg shell

8 mya- Gallus genus formed8 mya- Gallus genus formed

3-4 mya- Gallus gallus chicken species 3-4 mya- Gallus gallus chicken species formedformed

7500 BCE domestication SE Asia7500 BCE domestication SE Asia

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Background HistoryBackground History

Egg + Sperm = Fertilization -> Egg + Sperm = Fertilization ->

Egg + no sperm = Egg + no sperm =

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Health - AllergiesHealth - Allergies

Cause from ovalbumin Cause from ovalbumin NOTNOT the the yolkyolk

Ovalbumin mounts an attack and Ovalbumin mounts an attack and human immune system over human immune system over attacks.attacks.

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Health- Salmonella Health- Salmonella enteritidisenteritidis: Symptoms: Symptoms 6-72 hrs6-72 hrs Gastrointestinal IllnessGastrointestinal Illness 1:10,000 eggs w/ Salmonella1:10,000 eggs w/ Salmonella ““Hugging the toilet”Hugging the toilet”

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Health- Salmonella: Most Health- Salmonella: Most Susceptible Susceptible

Young & Old: WHY???Young & Old: WHY??? How does it spread???How does it spread??? SO:SO: Buy Refrigerated Buy Refrigerated Cook completely Cook completely

– 140ºF 5 min 140ºF 5 min – 160ºF 1 min.160ºF 1 min.

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Health- Salmonella: Safe Health- Salmonella: Safe AlternativeAlternative

Pasteurized @ 130-140ºFPasteurized @ 130-140ºF

Liquid eggsLiquid eggs

Dried whitesDried whites

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Health - CholesterolHealth - Cholesterol

1970’s-1980’s PHOBIA1970’s-1980’s PHOBIA

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Health – Cholesterol: Health – Cholesterol: Misconception Misconception

1 Lg egg: 215 mg = meat 50 mg1 Lg egg: 215 mg = meat 50 mg

Blood cholesterol Heart RiskBlood cholesterol Heart Risk

Blood cholesterol influenced by Blood cholesterol influenced by Saturated fatsSaturated fats. HOWEVER: most egg . HOWEVER: most egg yolks are yolks are unsaturated fatsunsaturated fats..

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Health – Cholesterol: Health – Cholesterol: SubstitutesSubstitutes REALREAL egg whites

Imitation yolk: Veggie Oil

Milk Solids

Gums

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Dissecting The EggDissecting The Egg

1.1. CuticleCuticle

2.2. ShellShell

3.3. WhitesWhites

4.4. YolkYolk

5. Chalaza5. Chalaza

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Dissecting the Egg- Cuticle/ColorDissecting the Egg- Cuticle/Color

Color due to proteinaceous Color due to proteinaceous cuticlecuticle

Cuticle plugs the poresCuticle plugs the pores Color has no relation to Taste or Color has no relation to Taste or

nutritional valuenutritional value Color relates literally…Color relates literally… Ex. Araucana hens lay blue Ex. Araucana hens lay blue

eggseggs

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Dissecting the Egg: ShellDissecting the Egg: Shell

Derived from Hen’s uterine lining Derived from Hen’s uterine lining cellscells

Shell composed of Calcium Shell composed of Calcium CarbonateCarbonate

10K10K

Air pocketsAir pockets

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Dissecting the Egg: ChalazaDissecting the Egg: Chalaza

2 chords that anchor the yolk2 chords that anchor the yolk

Will rotate while suspended in the Will rotate while suspended in the middle of the eggmiddle of the egg

Function: Provides stability & Function: Provides stability & cushioning cushioning

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Dissecting the Egg: Dissecting the Egg: YolkYolk

YOLK= YOLK= Fuel: ¾ calories, iron, thiamin, & Fuel: ¾ calories, iron, thiamin, & vitamin Avitamin A

Pigment Plant xanthophlls (from what hen Pigment Plant xanthophlls (from what hen ate) fat & protein synthesized in the ate) fat & protein synthesized in the hen’s liverhen’s liver

White Yolk: White Yolk: Yellow Yolk Yellow Yolk

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Dissecting the Egg: WhitesDissecting the Egg: Whites

Thick & Thin WhitesThick & Thin Whites Function: Function:

– defense against Infectiondefense against Infection– protection protection – nourishmentnourishment

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Whites: NourishmentWhites: Nourishment

ContainsContains Trace mineralsTrace minerals Fatty materialsFatty materials Vitamin (riboflavin)Vitamin (riboflavin) GlucoseGlucose Water - 90%Water - 90% Proteins - 10% Proteins - 10%

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Whites: DefensesWhites: Defenses Acts as the Acts as the primary primary defense against defense against

infection & predators infection & predators

Protein that blocks digestive enzymesProtein that blocks digestive enzymes

Protein binds to iron & vitamins so Protein binds to iron & vitamins so NOTNOT useful to other speciesuseful to other species

Protein inhibits virus reproductionProtein inhibits virus reproduction

Protein that digests bacteria cell wallProtein that digests bacteria cell wall

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Whites: The Proteins (4 total)Whites: The Proteins (4 total)

Ovotransferrin (1Ovotransferrin (1stst to coagulate) to coagulate)

Carries iron to developing chickCarries iron to developing chick Prevents bacteria from using ironPrevents bacteria from using iron

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Whites: The Proteins (4 total)Whites: The Proteins (4 total)

Ovalbumin (most plentiful - Ovalbumin (most plentiful - approximately 70%)approximately 70%)– Reactive sulfur groupsReactive sulfur groups

Ovomucin and Ovomucoid (less than Ovomucin and Ovomucoid (less than 2%)2%)– Jelly-like consistencyJelly-like consistency– Pulls together soupy proteins into Pulls together soupy proteins into

organized structure organized structure –

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Whites: Other ProteinsWhites: Other Proteins

Globulins – lysozymeGlobulins – lysozyme

Avidin – large quantities can Avidin – large quantities can cause biotin deficiencycause biotin deficiency

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Whites:Whites: Thick Thick & Thin= Albumen& Thin= Albumen

Adds Adds THICKTHICK layers to layers to the membrane whites the membrane whites (albumen) in 4 layers (albumen) in 4 layers for for THICK THICK & THIN & THIN albumen for albumen for consistency consistency

Secreted by Oviduct Secreted by Oviduct from protein secreting from protein secreting cells.cells.

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Eggcelent FactsEggcelent Facts Commercial chicken can lay 250-290 Commercial chicken can lay 250-290

eggseggs Raw eggs in shell keep for 3-5 weeks Raw eggs in shell keep for 3-5 weeks

in refrigeratorin refrigerator Egg consumption has declined from Egg consumption has declined from

320 eggs per person in 1967 to 235 in 320 eggs per person in 1967 to 235 in 1990 and has increased to 254 in 1990 and has increased to 254 in 2003.2003.

Weight - 15 to 30 oz.Weight - 15 to 30 oz. ¼ hen’s energy goes in to egg making¼ hen’s energy goes in to egg making

– ½ for a duck½ for a duck

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Good Egg; Badddd EggGood Egg; Badddd Egg

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Good Egg Baddd EggGood Egg Baddd Egg

GradesGrades Thick Thick WhitesWhites

Firm Firm Round Round YolksYolks

AAAA YESYES YESYES

AA Less ThickLess Thick WeakerWeaker

BB Fast Fast spreadingspreading

Easily Easily BreaksBreaks

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Good Egg Baddd EggGood Egg Baddd Egg Characteristics of a Good Egg:Characteristics of a Good Egg:

– IntactIntact– Uncontaminated eggUncontaminated egg– Strong ShellStrong Shell– Firm YolkFirm Yolk– Thick WhiteThick White– HOW DO YOU KNOW W/O BREAKING HOW DO YOU KNOW W/O BREAKING

THE EGG?THE EGG?

– Bad eggs Normally when Hen lays eggs Bad eggs Normally when Hen lays eggs at the end of the laying yearat the end of the laying year

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Good Egg Bad Egg: CANDLINGGood Egg Bad Egg: CANDLING

Spots cracksSpots cracks Large air cellsLarge air cells ““Meat spots”Meat spots”

– Brown in whitesBrown in whites– Tissue slough off from Tissue slough off from

oviduct walloviduct wall Blood spots on yolkBlood spots on yolk

– Burst capillaries in hen Burst capillaries in hen ovary/yolk sacovary/yolk sac

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Eggs = A Hot Potato?Eggs = A Hot Potato? Eggs quickly gatheredEggs quickly gathered

Immediately CooledImmediately Cooled

(USA) Wash in warm water(USA) Wash in warm water

Sold 2 days afterSold 2 days after

Deterioration: 1 Day Room Temp = 4 Deterioration: 1 Day Room Temp = 4 Days in FridgeDays in Fridge

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Why?Why?

Whites & Yolks Whites & Yolks more alkaline more alkaline (dec. Acid)(dec. Acid)

Moisture Moisture decreasesdecreases

Calcium Calcium Carbonate Carbonate dissolvesdissolves

pH pH ThenThen

pH pH LaterLater

WhitesWhites 6.0 pH6.0 pH 6.6 pH6.6 pH

YolkYolk 7.7 pH7.7 pH 9.2 pH9.2 pH

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StorageStorage

FREEZING: Air tight containerFREEZING: Air tight container

Separate from shellSeparate from shell WhitesWhites YolksYolks

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Egg Versatility!Egg Versatility!

FryFry BoilBoil Deep FriedDeep Fried BakedBaked RoastedRoasted PickledPickled FermentedFermented

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Coagulation Coagulation

1. Egg proteins folded chains of Amino Acids

2. ADD Heat and chains UNFOLD

3. Unfolding and chains bond to each other for a continuous meshwork

1.

2.

3.

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Coagulation cont…Coagulation cont…

Egg white coagulation starts at Egg white coagulation starts at 144ºF and sets at 150ºF144ºF and sets at 150ºF

YolkYolk thickens at 150F and sets at thickens at 150F and sets at 158ºF158ºF

YolkYolk and white mixed set at 165ºF and white mixed set at 165ºF

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Eggs + Ingredients = Eggs + Ingredients = Coagulation?Coagulation?

LiquidLiquid - raises thickening temp - raises thickening temp

SugarSugar - raises thickening temp - raises thickening temp

Acid and saltAcid and salt - thickening and - thickening and coagulation at lower tempscoagulation at lower temps– Proteins do not have chance to unfold Proteins do not have chance to unfold

completely completely

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FoamFoam

Egg white filled with airEgg white filled with air Proteins unfold and bond together Proteins unfold and bond together

(whisking causes protein to unfold)(whisking causes protein to unfold) 4 stages4 stages

– ““foamy”foamy”– ““soft peak” soft peak” – ““stiff peak”stiff peak”– ““dry”dry”

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Foam cont.Foam cont. Other ingredientsOther ingredients

– SaltSalt - increases whipping - increases whipping time/decreases foam stabilitytime/decreases foam stability

– Sugar Sugar - delays foaming/reduces volume - delays foaming/reduces volume and lightness BUT improves stabilityand lightness BUT improves stability

– Egg yolk, oil/fatEgg yolk, oil/fat - interfere with foam - interfere with foam

Ex. Mousses, soufflés, angle food cake, and meringues. Foams help LIGHTEN a dish

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CustardsCustards

West: custards are milk or creamWest: custards are milk or cream Fruit & Veggies can cause Fruit & Veggies can cause

curdlingcurdling

EX. Crème Brûlée, Cheesecake, flan, & Quiche

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Green Eggs and HamGreen Eggs and Ham

Green Green yolks yolks areare

harmlesharmlesss

Ferrous Ferrous sulfide sulfide

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Power Point AuthorPower Point Author

Shauna HenleyShauna HenleyThe University of Vermont

Foods and NutritionBasic Concepts of Food