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EGGS!. 1. What we’re doing today folks!. History Etiology Health Dissecting the egg Good Egg, Bad Egg Cooking. 2. Background History . 300 mya- eggs laying in the ocean 100 mya- mineralized egg shell 8 mya- Gallus genus formed 3-4 mya- Gallus gallus chicken species formed
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EGGS! 1
What we’re doing today folks! • History • Etiology • Health • Dissecting the egg • Good Egg, Bad Egg • Cooking 2
Background History • 300 mya- eggs laying in the ocean • 100 mya- mineralized egg shell • 8 mya- Gallus genus formed • 3-4 mya- Gallus gallus chicken species formed • 7500 BCE domestication SE Asia 3
Background History • Egg + Sperm = Fertilization -> • Egg + no sperm = 4
Health - Allergies • Cause from ovalbumin NOT the yolk • Ovalbumin mounts an attack and human immune system over attacks. 5
Health- Salmonella enteritidis: Symptoms • 6-72 hrs • Gastrointestinal Illness • 1:10,000 eggs w/ Salmonella • “Hugging the toilet” 6
Health- Salmonella: Most Susceptible • Young & Old: WHY??? • How does it spread??? • SO: • Buy Refrigerated • Cook completely • 140ºF 5 min • 160ºF 1 min. 7
Health- Salmonella: Safe Alternative • Pasteurized @ 130-140ºF • Liquid eggs • Dried whites 8
Health - Cholesterol • 1970’s-1980’s PHOBIA 9
Health – Cholesterol: Misconception • 1 Lg egg: 215 mg = meat 50 mg • Blood cholesterol Heart Risk • Blood cholesterol influenced by Saturated fats. HOWEVER: most egg yolks are unsaturated fats. 10
Health – Cholesterol: Substitutes • REALegg whites • Imitation yolk: Veggie Oil • Milk Solids • Gums 11
Dissecting The Egg • Cuticle • Shell • Whites • Yolk • 5. Chalaza 12
Dissecting the Egg- Cuticle/Color • Color due to proteinaceous cuticle • Cuticle plugs the pores • Color has no relation to Taste or nutritional value • Color relates literally… • Ex. Araucana hens lay blue eggs 13
Dissecting the Egg: Shell • Derived from Hen’s uterine lining cells • Shell composed of Calcium Carbonate • 10K • Air pockets 14
Dissecting the Egg: Chalaza • 2 chords that anchor the yolk • Will rotate while suspended in the middle of the egg • Function: Provides stability & cushioning 15
Dissecting the Egg: Yolk • YOLK= Fuel: ¾ calories, iron, thiamin, & vitamin A • Pigment Plant xanthophlls (from what hen ate) fat & protein synthesized in the hen’s liver • White Yolk: Yellow Yolk 16
Dissecting the Egg: Whites • Thick & Thin Whites • Function: • defense against Infection • protection • nourishment 17
Whites: Nourishment • Contains • Trace minerals • Fatty materials • Vitamin (riboflavin) • Glucose • Water - 90% • Proteins - 10% 18
Whites: Defenses • Acts as the primary defense against infection & predators • Protein that blocks digestive enzymes • Protein binds to iron & vitamins so NOT useful to other species • Protein inhibits virus reproduction • Protein that digests bacteria cell wall 19
Whites: The Proteins (4 total) • Ovotransferrin (1st to coagulate) • Carries iron to developing chick • Prevents bacteria from using iron 20
Whites: The Proteins (4 total) • Ovalbumin (most plentiful - approximately 70%) • Reactive sulfur groups • Ovomucin and Ovomucoid (less than 2%) • Jelly-like consistency • Pulls together soupy proteins into organized structure 21
Whites: Other Proteins • Globulins – lysozyme • Avidin – large quantities can cause biotin deficiency 22
Whites: Thick & Thin= Albumen • Adds THICK layers to the membrane whites (albumen) in 4 layers for THICK & THIN albumen for consistency • Secreted by Oviduct from protein secreting cells. 23
Eggcelent Facts • Commercial chicken can lay 250-290 eggs • Raw eggs in shell keep for 3-5 weeks in refrigerator • Egg consumption has declined from 320 eggs per person in 1967 to 235 in 1990 and has increased to 254 in 2003. • Weight - 15 to 30 oz. • ¼ hen’s energy goes in to egg making • ½ for a duck 24
Good Egg Baddd Egg • Characteristics of a Good Egg: • Intact • Uncontaminated egg • Strong Shell • Firm Yolk • Thick White • HOW DO YOU KNOW W/O BREAKING THE EGG? • Bad eggs Normally when Hen lays eggs at the end of the laying year 27
Good Egg Bad Egg: CANDLING • Spots cracks • Large air cells • “Meat spots” • Brown in whites • Tissue slough off from oviduct wall • Blood spots on yolk • Burst capillaries in hen ovary/yolk sac 28
Eggs = A Hot Potato? • Eggs quickly gathered • Immediately Cooled • (USA) Wash in warm water • Sold 2 days after • Deterioration: 1 Day Room Temp = 4 Days in Fridge 29
Why? • Whites & Yolks more alkaline (dec. Acid) • Moisture decreases • Calcium Carbonate dissolves 30
Storage • FREEZING: Air tight container • Separate from shell • Whites • Yolks 31
Egg Versatility! • Fry • Boil • Deep Fried • Baked • Roasted • Pickled • Fermented 32
Coagulation 1. 2. • Egg proteins folded chains of Amino Acids • ADD Heat and chains UNFOLD • Unfolding and chains bond to each other for a continuous meshwork 3. 33
Coagulation cont… • Egg white coagulation starts at 144ºF and sets at 150ºF • Yolk thickens at 150F and sets at 158ºF • Yolk and white mixed set at 165ºF 34
Eggs + Ingredients = Coagulation? • Liquid - raises thickening temp • Sugar - raises thickening temp • Acid and salt - thickening and coagulation at lower temps • Proteins do not have chance to unfold completely 35
Foam • Egg white filled with air • Proteins unfold and bond together (whisking causes protein to unfold) • 4 stages • “foamy” • “soft peak” • “stiff peak” • “dry” 36
Foam cont. • Other ingredients • Salt - increases whipping time/decreases foam stability • Sugar - delays foaming/reduces volume and lightness BUT improves stability • Egg yolk, oil/fat - interfere with foam Ex. Mousses, soufflés, angle food cake, and meringues. Foams help LIGHTEN a dish 37
Custards • West: custards are milk or cream • Fruit & Veggies can cause curdling EX. Crème Brûlée, Cheesecake, flan, & Quiche 38
Green Eggs and Ham • Green yolks are • harmless • Ferrous sulfide 39
Power Point Author • Shauna Henley • The University of Vermont • Foods and Nutrition • Basic Concepts of Food