EGG CHARACTERISTICS4th Revision, 12 Nopember 2010

Nugraha E. Suyatma and Joko Hermanianto

Department of Food Science and Technology

Bogor Agricultural University

1

EGGAn 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.

2Which came first,

the chicken or the egg?

Edible egg:

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

3

Commercial Egg:

• These are hen eggs in shell, suitable for consumption in the state, or use by food industries, excluding broken eggs and boiled eggs (CEE Regulation No. 1907/90).

• Most laying hens are White Leghorns .

4

Formation of the egg

5

• 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

Section of oviduct Approximate time egg spends in this section

Functions of section of oviduct

1 Funnel (infundibulum)

15 minutes Receives yolk from ovary. If live sperm present, fertilisation occurs here (commercially produced table eggs are not fertilised)

2 Magnum 3 hours Inner and outer shell membranes are added, as are some water and mineral salts

3 Isthmus 1 hour Albumen (white) is secreted and layered around the yolk

4 Shell gland (uterus)

21 hours Initially some water is added, making the outer white thinner. Then the shell material (mainly calcium carbonate) is added. Pigments may also be added to make the shell brown

5 Vagina/cloaca less than 1 minute

The egg passes through this section beforelaying. It has no other known function in theegg’s formation

7

Video of the Hen and Egg Formation

Anatomy of an Egg

1. Eggshell2. Outer membrane3. Inner membrane4. Chalaza5. Exterior albumen6. Middle albumen7. Vitelline membrane8. Nucleus of pander9. Germinal disk10.Yellow yolk11.White yolk12.Internal albumen13.Chalaza14.Air cell15.Cuticula 8

9

10

11

Video of the Egg composition

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 through has a thin outermost coating called the bloom or cuticle that helps keep out bacteria and dust.

• Mucin : covered shell and pores12

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

13

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

14

Consist of 4 parts: inner thick, inner thin white, outer thick white dan outer thin white.

cloudy appearance due to CO2 content.

ALBUMEN

15

Albumen

Proteins Lipids Carbohydrates Ash Water

9.7-10.6%, 0.03% 0.4-0.9% 0.5-0.6%

87.9-89.4%

Composition of Albumen (Powrie 1973)

16

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.

Ovalbumin 54%Conalbumin 13%Ovomucoid 11%Lysozyme 3.5%Globulins (G2, G3) 8.0 %Ovomucin 1.5%

Other protein components include, flavoprotein (0.8%), ovoglycoprotein (0.5%), ovomacroglobulin (0.5%), ovoinhibitor (0.l%) and avidin (0.05%).

MAJOR PROTEINS IN ALBUMEN OF TOTAL PROTEINS (Powrie 1973)

17

Egg white contains approximately 40 different proteins:

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.

18

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.

19

CHEMICAL COMPOSITION OF EGG

20

Chemical composition of eggs

Animal Water (%)

Protein (%)

Lipid (%)

CHO(%)

Ash (%)

Chicken 73,7 12,9 11,5 0,9 1

Duck 70,4 13,3 14,5 0,7 1,1

Goose 70,4 13,9 13,3 1,5

Pigeon 72,8 13,8 12 0,8 0,9

Quail 73,7 13,1 11,1 1 1,1

Ostrich 72,6 13,1 11,8 1,7 0,8

Turtle 66,7 16,5 11,6 3,3 1,9

21

Composition of egg

Component (%)Telur Utuh

Putih telur

Kuning telur

Kulittelur

Water 37 87,6 51,1 -Protein 12,9 10,9 16 4Lipid 11,5 - 30 -Carbohydrate 1,1 1,1 1,1 -

Free Carbohydrate 0,3 0,4 0,2 -

Ash 1 0,7 1,7 -Mineral 11,7 1 2 96

22

Vitamin

contain most of the recognised vitamins with the exception of vitamin C

23

VITAMINS

Component Amount per 100 g egg

Vitamin A 190 µg

Vitamin D 1,8 µg

Vitamin E 1,1 mg

Vitamin C none

Thiamin (B1) 0,09 mg

Riboflavin (B2) 0,47 mg

Niacin 0.1 mg

Vitamin B6 0.12 mg

Folate 50 µg

Vitamin B12 2,5 µg Biotin 20 µg

Panthotenic acid

1.77 µg24

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.

25

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.

26

Fatty acid content in 100 g of fresh yolk

Fatty Acid Gram

Saturated 1.59

Miristat (14:0) 0.02

Palmitat (16:0) 1.14

Stearat (18:0) 0.40

Monounsaturated 1.95

Palmitoleat (16:1) 0.15

Oleat (18:1) 1.78

Eicosenoat (20:1) 0.01

Polyunsaturated 0.70

Linoleat (18:2) 0.59

Linolenat (18:3) 0.02

Arakidonat (20:4) 0.07

Dokosaheksanoat (22:6) 0.02

Cholesterol 0.21

TOTAL 4.43 27

Chemical composition change:

Liquid /Dry Egg

(per100g)

Liquid*/Frozen Dried

Whole Eggs Yolk White Whole Eggs Yolk Stabilized

White

SOLIDS-g 24.80 43.20 11.0 96.3 97.3 93.5

pH-g 7.8 6.7 8.8 8.7 6.5 6.8

PROTEIN-g 12.0 15.3 9.3 48.4 33.7 84.6

LIPIDS-g 9.71 23.0 0.076 39.2 52.9 0.407

FREE GLUCOSE-g

<0.10 0.2 0.3 0.3 <0.1 0

ASH-g 0.80 1.4 0.4 3.4 3.3 3.6

MOISTURE-g 75.20 56.80 89.0 3.7 2.7 6.5

28

29

Important Nutritional Value of Egg

1. One medium egg contains between 4-5 grams of fat

2. High cholesterol• ~200 mg/egg

3. High in Complete Protein (EPR=93.7%); > milk (84.5%), fish (76%), beef meat (74.3%), soy bean (72.8%), corn (60%)

4. Little to no CHO

5. High in vitamins & minerals• Vitamins ADEK, some B vitamins, selenium, iodine,

zinc, iron, copper

Energy value of eggs

Protein

• 78 kilocalories (324 kilojoules) • only around 3% of the average energy

requirement of an adult man and 4% for an adult woman.

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.

30

Functional Properties of Egg

31

1. Flavor, color, nutrition2. Foaming agent3. Emulsifying agent4. Aids in thickening/structure5. Binding/coating agent6. Leavening agent

FOAMING PROPERTIES

32

1. Air trapped in a liquid

2. In egg foam, air trapped by protein.

3. Denatured and then coagulates

4. Heat expands protein/air• Important to souffles,

meringues, omelet, and sponge cake.

EMULSIFIER CAPACITY

Egg yolk is a source of lecithin, an emulsifier and surfactant.

Lechitin is 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

33

Properties ApplicationThickening Eggs thicken foods like custards puddings, sauces,

and creamy fillings

Leavening Souffles, sponge & butter cakes, quick breads, andpuffy omelets are leavened by eggs

Coating Meat dishes, breads, and cookies are some foodswith egg components as the base ingredients forcoatings

Binding Eggs bind other ingredients for making meat loaves,casseroles, and croquettes

Emulsifying Eggs prevent mixture separation in mayonnaise,salad dressing, and cream puff filling

Clarifying Tiny particles are coagulated in soups and coffee tocreate a clear solution

RetardingCrystallization

Crystallization of sugar is slowed in cake icings andcandies

34

ANTIMICROBIAL AND ALERGEN ON ALBUMIN

• LYSOZYME• Immunoglobulin E (IgE)

memicu histamin• OVOMUCIN (hambat enzim

tripsin)• AVIDIN: mengkompleks biotin

(Avidin+Biotin komplek): Biotin tak dpt dicerna

35

Daily NeededNutritional analysis of egg without its shell

For a medium egg (Av 58g)  

Constituent of Egg Amount per egg

% of Reference Nutrient Intake (RNI)

Amount per 100g egg

For adult female 19-50

years

For adult male19-50

years

Weight1   51.6 - - 100.0

Water g 38.8 - - 75.1

Energy kjoules/ kcalories

324/78 4 3 627/151

Protein g 6.5 14 12 12.5

Carbohydrate g trace - - trace

Fat g 5.8 ** ** 11.2

Inc saturated f.a. g 1.7 ** ** 3.2

Monounsaturated f.a

g 2.3 ** ** 4.4

Polyunsaturated fa.t

g 0.9 ** ** 1.7

36

Benefit of Egg Components• Sialic acid could prevent infection • Immunoglobulin in 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

37

Allergen in Egg• There are 4 proteins in egg white may provoque

an allergy:- ovomucoid (11%)

- ovalbumin (54%)- ovotransferrin (12%)- lysozyme (3.5%)

38

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

39

EGG QUALITY

40

Egg Quality

41

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.

Shape Index of Egg

Ideal shape (USDA)

42

Shape index of egg = A/B x 100A = the biggest diameter (cm)B = The longest of length (cm)

Candling

43

• 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.

44

45

46

47

Video: Candling an egg

48

Egg Grading

Grade

size

49

Sizing

50

Peewee: less than 42 g 

Small: at least 42 g

Medium: at least 49 g

Large: at least 56 g

Extra Large: at least 64 g

Jumbo: at least 70 g

51

• Sizing is not related to grading in any way.• Eggs are sold in cartons by various sizes determined by a

minimum weight for a dozen eggs in their shell.

Grading

52

Grade AA Grade A Grade B Break Out Appearance

Covers a small area. Covers a moderate area.

Covers a wide area.

Albumen Appearance

White is thick and stands high; chalaza prominent.

White is reasonably thick, stands fairly high; chalaza prominent.

Small amount of thick white; chalaza small or absent. Appears weak and watery.

Yolk Appearance

Yolk is firm, round and high.

Yolk is firm and stands fairly high.

Yolk is somewhat flattened and enlarged.

Shell Appearance

Approximates usual shape; generally clean,* unbroken; ridges/rough spots that do not affect the shell strength are permitted.

Abnormal shape; some slight stained areas permitted; unbroken; pronounced ridges/thin spots permitted.

Usage Ideal for any use, but are especially desirable for poaching, frying and cooking in shell.

Ideal for any use, but are especially desirable for poaching, frying and cooking in shell.

Good for scrambling, baking, and as an ingredient in other foods.

Grading

53

GRADE A: sold at retail store

yolk is round, well centred

white is thick

small air cell (less than 5 mm deep)

shell is clean, uncracked and of normal shape

GRADE B : only a small percentage sold at retail stores; most go to further processing market

yolk is slightly enlarged or flattened

white is moderately thin

shell uncracked 

GRADE C: not sold at retail stores; all go to further processing market

yolk is enlarged or flattened

white is thin and watery

shell may be cracked and stained

Video: EXTERIOR EGG QUALITY

54

Grade

Grade Grade AA egg covers small area and stands high; white is thick and firm; yolk is high and round.

Grade A egg covers moderate area; white is reasonably firm and stands fairly high; yolk is

high.

There are three consumer grades for eggs: U.S. Grade AA, A, and B. The grade is determined by the interior

quality of the egg and the appearance and condition of the egg shell. Eggs of any quality grade may differ in

weight (size). 55

Video: BROKEN OUT EGG QUALITY

56

Egg White Index

• Egg white index (EWI)

Height of thick albumen EWI =

diameter of thick albumen (longest+shortest)/2

Newlaid Egg has the value: 0.050 – 0.174

Good quality if the value: 0,090 – 0,12057

Egg Yellow Index (EYI)

height of yolk EYI =

diameter of yolk

Good quality if EYI : 0,33 – 0,50

Average value: 0.42.

58

Haugh Unit• Haugh unit (HU)

HU= 100 log [h-(√G(3w0.37-100)+1,9]

100HU= Haugh unit

h = heigh of thick albumen (mm)

G= 32,2

w= whole egg weight (g)

59

Fresh egg: HU=100Good quality: HU = 75; acceptable until 50Bad quality (Spoiled egg): HU < 50

Changes in quality as the egg ages

60

Egg Handling• Egg quality is affected by temperature and

relative humidity of storage room.• Need to preservation

Egg preservation principles:• Avoid spoilage microorganisme enter• Minimize the loss of water and gas from

egg.Aplication:• freezing, chilling, dry packaging, coating

with essential oil, dipping in various liquid.61

62

63

Video: Commercial Egg Production

64

Video: Egg Processing

65

Commercial Egg Production and Processing

Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University 66

Egg Production

The objective of this presentation is to provide a general overview of commercial egg production and processing.

The slides are ordered in a sequential series as they occur in the production cycle.

This particular egg production facility is considered an “in-line” operation. This means the eggs are produced and packaged for shipping to retail markets on the farm. There are also many “off-line” operations that produce eggs in one location and transport them to another location for processing.

67Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

On the horizon is an in-line commercial egg production facility. This facility is vertically integrated or self-contained, i.e., the company owns the feed mill, hens, buildings, egg processing facility, and transportation vehicles.

68Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

A

A

A

This facility represents one level of vertical integration, the feed mill. Based on demand, raw grains (from bins “A”) are mixed into designated poultry rations and augured (“B”) to the layer houses.

B

69Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

The auger system delivers grain into high-rise layer houses (“C”). These houses are approximately 500 feet long and may contain as many as 150,000 laying hens.

C

C

70Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

This is a view of the inside of a layer facility. Hens are housed on slanted wire-mesh floors. Nipple waterers (“A”) serve as the hen’s source of water and the feed is transported through the house via an auger system in feeders (“B”).

B

B

B

A

B

71Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

This is another view of the egg transporting mechanisms within a layer house. The use of advanced mechanical engineering has greatly reduced the occurrence of human egg handling to the point that eggs are rarely touched by human hands.

72Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

As the eggs reach the end of each level, automatic collectors place the eggs into plastic egg handlers (“D”). Plastic egg handlers carry the eggs directly to the egg processing facility via a large overhead belt.

DD D

73Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

These eggs are traveling to the egg processing/breaker facility.

74Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

Eggs are mechanically washed with a mild detergent and sanitized (“E”). Eggs are washed in 120oF water.

E

E

75Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

Here the eggs are entering the first stage in the egg grading process. The eggs are evaluated by an automated computerized detection system. Eggs are graded into categories of AA, A, B, and Loss Quality Standards.

76Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

Brushes transport eggs away from the egg graders to the packaging area of the plant. It is at this point that eggs will either be placed into cartons or be sent to the breakers.

77Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

This is a view of the entire “carton line.” Each stack of cartons (blue, white, yellow, pink) represents a different egg size.

78Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

Eggs are mechanically placed into cartons for shipping to the grocery market.

79Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

Eggs awaiting processing within the plant are placed on plastic skids. These skids are washed and sanitized on a daily basis.

80Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

On the left, eggs are stacked in cardboard flats for shipment to the retail market. Eggs on the right are stacked in plastic flats and are awaiting transfer to the egg further processing (breaker) room. Again, plastic is used inside the plant for sanitation and recycling purposes.

81

82Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

This is an egg breaker machine. This machine cracks the egg shells and separates the yolk (yellow) from the albumen (white). The separation process works exactly like a household egg strainer. This machine will process 18,000 eggs per hour.

83Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

This is also egg breaker machine. However, this machine will process 500,000 eggs per hour.

84Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

85

Video: Egg Breaker

86

Video: Egg Breaker

These are bulk bins full of pasteurized egg yolks awaiting shipment. Egg pasteurization occurs at 145oF for seven minutes for 3,000 pounds of egg.

87

Processed egg products leave the facility via 1/2 gallon “milk” cartons, bagged product, and bulk semi-trailers. Processed egg products also include hard-boiled eggs.

88Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

Eggshells are processed in the plant. The shells have been dried and ground for use in animal feeds and other products.

89Courtesy of Ryan A. Meunier & Dr. Mickey A. Latour; Purdue University

TERIMAKASIH

90

QUIZ TIME..TULISKAN NAMA DAN NRP ANDA !

******************************

SUKSES ITU LAHIR DARI KEJUJURAN, KEULETAN DAN KETEKUNAN YANG

DIIRINGI DENGAN DOA

******************************