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EGG CHARACTERISTICS 4th Revisi on , 1 2 Nop ember 20 10

EGG CHARACTERISTICS 4th Revisi on , 1 2 Nop ember 20 10. Nugraha E. Suyatma and J oko Hermanianto Department of Food Science and Technology Bogor Agricultural University. EGG.

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EGG CHARACTERISTICS 4th Revisi on , 1 2 Nop ember 20 10

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  1. EGG CHARACTERISTICS 4th Revision, 12Nopember 2010 Nugraha E. Suyatmaand JokoHermanianto Department of Food Science and Technology Bogor Agricultural University

  2. EGG An egg is a round or oval cell laid by the female of any number of different species, consisting of an ovum surrounded by layers of membranes and an outer casing, which acts to nourish and protect a developing embryo. Which came first, the chicken or the egg?

  3. Edible egg: • Chicken egg • Quail egg • Duck egg • Goose egg • Ostrich egg • Turtle egg • Fish egg: roe and caviar

  4. Commercial Egg: • These are hen eggs in shell, suitable for consumption in the state, or use by food industries, excluding broken eggsand boiled eggs (CEE Regulation No. 1907/90). • Most laying hens are White Leghorns.

  5. Formation of the egg • The egg is formed gradually over a period of about 25 hours. • The female chick (Hen) has up to 4000 tiny ova (reproductive cells), from some of which full-sized yolks may develop when the hen matures. • Each yolk (ovum) is enclosed in a thin-walled sac, or follicle, attached to the ovary • The mature yolk is released when the sac ruptures, and is received by the funnel of the left oviduct

  6. Video of the Hen and Egg Formation

  7. Anatomy of an Egg • Eggshell • Outer membrane • Inner membrane • Chalaza • Exterior albumen • Middle albumen • Vitelline membrane • Nucleus of pander • Germinal disk • Yellow yolk • White yolk • Internal albumen • Chalaza • Air cell • Cuticula

  8. Video of the Egg composition

  9. SHELL (10 %) • calcium carbonate (CaCO3) 94-97 %, 3-6 % Organic material and Pigment • Shell strength is depend on the content of CaCO3, Mg, P, dan vit D • Thickness: 0.2-0.4 mm • Pores: 700 pores/cm2 = 17,000 tiny pores • Semipermeable membrane: air and moisture can pass throughhas a thin outermost coating called the bloom or cuticle that helps keep out bacteria and dust. • Mucin : covered shell and pores

  10. INNER AND OUTER MEMBRANES AND AIR CELL INNER AND OUTER MEMBRANES Lye between the eggshell and egg white, these two transparent protein membranes provide efficient defense against bacterial invasion. If you give these layers a tug, you’ll find they’re surprisingly strong. They’re made partly of keratin, a protein that’s also in human hair. AIR CELL • An air space forms when the contents of the egg cool and contract after the egg is laid

  11. ALBUMEN (60 %) • The egg white is known as the albumen, which comes from albus, the Latin word for “white.” • contain approximately 40 different proteins: • OVALBUMIN, CANALBUMIN, OVOTRANSFERIN, LYSOZYM, OVOMUCIN, AVIDIN, ETC

  12. ALBUMEN • Consist of 4 parts: inner thick, inner thin white, outer thick whitedanouter thin white. • cloudy appearance due to CO2content.

  13. Albumen The egg white is approximately two-thirds of the total egg's weight out of its shell with nearly 90% of that weight coming from water. Composition of Albumen (Powrie 1973)

  14. MAJOR PROTEINS IN ALBUMEN OF TOTAL PROTEINS (Powrie 1973) Egg white contains approximately 40 different proteins: Other protein components include, flavoprotein (0.8%), ovoglycoprotein (0.5%), ovomacroglobulin (0.5%), ovoinhibitor (0.l%) and avidin (0.05%).

  15. YOLK • Less water, more protein and fat than the white egg • Contains most of the vitamins and minerals of the egg, including Fe, vitamin A, vitamin D, phosphorus, calcium, thiamine, and riboflavin. • Source of lecithin (emulsifier). • Yolk color ranges from just a hint of yellow to a magnificent deep orange, according to the feed and breed of the hen. • Umur: kuning telur mengabsorbsi air dari albumen: ukuran kuning telur membesar , strukturnya meregang, membran vitelin rusak, bentuk lebih flat.

  16. CHALAZAE AND VITELIN CHALAZAE • Opaque ropes of egg white, the chalazae hold the yolk in the center of the egg. Like little anchors, they attach the yolk’s casing to the membrane lining the eggshell. The more prominent they are, the fresher the egg. Vitelline Membrane • The clear casing that encloses the yolk.

  17. CHEMICAL COMPOSITION OF EGG

  18. Chemical composition of eggs

  19. Composition of egg

  20. Vitamin contain most of the recognised vitamins with the exception of vitamin C

  21. Minerals • Iodine  thyroid hormone • Phosphorus  for bone health. • Zinc  for wound healing, growth and fighting infection • Selenium  an important antioxidant • Calcium  for bone and growth structure and nervous function. • also contain significant amounts of iron, the vital ingredient of red blood cells.

  22. Lipids in Yolk • Egg lipids are found mostly in yolk, only 0,05% is contained in albumen. • Fatty acid content: monounsaturated (46.5%) > saturated (37.5%) > polyunsaturated (16.5%) • Highest fatty acid content: monounsaturated:oleic acid (18:1) approximately 40% from lipid total.

  23. Chemical composition change:

  24. Important Nutritional Value of Egg • One medium egg contains between 4-5 grams of fat • High cholesterol • ~200 mg/egg • High in Complete Protein (EPR=93.7%); > milk (84.5%), fish (76%), beef meat (74.3%), soy bean (72.8%), corn (60%) • Little to no CHO • High in vitamins & minerals • Vitamins ADEK, some B vitamins, selenium, iodine, zinc, iron, copper

  25. Energy value of eggs • 78 kilocalories (324 kilojoules) • only around 3% of the average energy requirement of an adult man and 4% for an adult woman. Protein Protein • 12.5% of the weight of the egg in both the yolk and the albumen. • Egg protein is of high biological value as it contains all the essential amino acids needed by the human body.

  26. Functional Properties of Egg • Flavor, color, nutrition • Foaming agent • Emulsifying agent • Aids in thickening/structure • Binding/coating agent • Leavening agent

  27. FOAMING PROPERTIES • Air trapped in a liquid • In egg foam, air trapped by protein. • Denatured and then coagulates • Heat expands protein/air • Important to souffles, meringues, omelet, andsponge cake.

  28. EMULSIFIER CAPACITY • Egg yolk is a source of lecithin, an emulsifier and surfactant. • Lechitinis a substance that helps an emulsion form, or helps keep an emulsion from separating • Aplication : • Mayonnaise • butter sauces • salad dressing • Stabilizer of bakery products • Whipped egg

  29. ANTIMICROBIAL AND ALERGENON ALBUMIN • LYSOZYME • Immunoglobulin E (IgE) memicuhistamin • OVOMUCIN (hambatenzimtripsin) • AVIDIN: mengkompleks biotin (Avidin+Biotin komplek): Biotin takdptdicerna

  30. Daily Needed

  31. Benefit of Egg Components • Sialic acid could prevent infection • Immunoglobulinin yolk can play a role as antibody. • PHOSVITIN has a function as food antioxidant. • Choline: aids brain function and enhances thinking capacity and memory. It is an important part of a neurotransmitter that helps preserve the integrity of the electrical transmission across the gaps between nerves. • Lutein and zeaxanthin: contribute to improving eye health and protecting eyes from ultraviolet rays

  32. Allergen in Egg • There are 4 proteins in egg white may provoque an allergy: - ovomucoid (11%) - ovalbumin (54%) - ovotransferrin (12%) - lysozyme (3.5%)

  33. Egg Allergy Symptoms • Egg allergy is like most food allergy reactions: It usually happens within minutes to hours after eating eggs. • the skin - in the form of red, bumpy rashes (hives), eczema, or redness and swelling around the mouth • the gastrointestinal tract - in the form of belly cramps, diarrhea, nausea, or vomiting • the respiratory tract - symptoms can range from a runny nose, itchy, watery eyes, and sneezing to the triggering of asthma with coughing and wheezing

  34. EGG QUALITY

  35. Egg Quality • Exterior egg quality – shell quality based on shell cleanliness, shell soundness, shell texture, shell shape. • Interior egg quality – based on relative viscosity of the albumen, freedom from foreign matter in the albumen, shape and firmness of the yolk, and freedom from yolk defects.

  36. Shape Index of Egg Idealshape (USDA) Shape index of egg = A/B x 100 A = the biggest diameter (cm) B = The longest of length (cm)

  37. Candling • Candling is the process of holding a strong light above or below the egg to observe: • cracks, checks and weak shells • blood or meat spots. • Egg air cell • size of yolk and its movement • double yolk, yolkless, etc. • Become familiar with interior quality.

  38. Video: Candling an egg

  39. Egg Grading size Grade

  40. Sizing

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