Lecture 3- Eggs

Question 1

Bird vs. mammalian eggs

Answer 1

Large vs. microscopic (egg is still largest cell in body)

Question 2

What % of the egg is shell, shell membranes

Answer 2

11%

Question 3

what % of egg is yolk

Answer 3

31%

Question 4

What % of egg is albumen

Answer 4

58%

Question 5

What % of altricial egg is yolk

Answer 5

20%

Question 6

What is the shell structure made of?

Answer 6

Cross linking CaCO3 (calcium carbonate or calcite)

Question 7

2 benefits of shell design

Answer 7

Permit gaseous exchange and nutrient (mineral) source

Question 8

Shell membranes are made up of

Answer 8

Tough mats of protein

Question 9

What is the formation, location, and function of air cells?

Answer 9

Liquid contracts as it cools, blunt end of egg btw inner + outer membranes, supply air to embryo at beginning of respiration

Question 10

3 functions of albumen

Answer 10

Insulation
Shock absorption
Nutrient source

Question 11

4 layers of albumen and % of total for each

Answer 11

Outer thin 23%
Firm/dense 57%
Inner thin 17%
Chalaziferous (thick white) 3%

Question 12

Purpose of chalazae

Answer 12

Extend to dense albumen and stabilize yolk position

Question 13

Yolk formation

Answer 13

Layers of nutrients for embryo surrounded by Vitelline membrane

Question 14

Blastodisk

Answer 14

White, circular, opaque, infertile

Question 15

Blastoderm

Answer 15

Oval, transparent center, opaque margins, fertile

Question 16

Blood spot

Answer 16

Blood vessel rupture in yolk follicle during ovulation

Question 17

Double yolk

Answer 17

2 yolks meet in oviduct (most common defect)

Question 18

4 germicidal properties (physical defense)

Answer 18

Shell- CaCO3 is a drying agent
Shell membranes- pores work as filters
Avidin- bind of biotin to interfere bacterial growth (in albumen)
Lysozyme- dissolves/lyses bacteria (in albumen)

Question 19

Where is most protein in an egg?

Answer 19

The yolk and albumen

Question 20

Where is almost all fat in an egg?

Answer 20

Yolk

Question 21

What % of egg contents is water

Answer 21

74%

Question 22

What % of egg contents is dry matter?

Answer 22

26%

Question 23

What % of egg contents is proteins?

Answer 23

13%

Question 24

What % of egg contents is fats?

Answer 24

11%

Question 25

What % of egg contents is carbohydrates?

Answer 25

1%

Question 26

What % of egg contents is minerals?

Answer 26

1%

Question 27

6 factors that vary egg composition

Answer 27

Type of bird, strain of bird, day-to-day variation, weather/climate, nutrition, disease

Question 28

What three minerals are mainly found in the shell?

Answer 28

Ca, Mg, P

Question 29

What 9 minerals are in eggs?

Answer 29

Ca, Cl, Fe, Mg, S, K, P, Na, I

Question 30

Egg protein names start with

Answer 30

Ovo/ Ova

Question 31

Egg’s are known as

Answer 31

Nature’s best protein

Question 32

What % of egg fats are triglycerides?

Answer 32

62%

Question 33

What % of egg fats are phospholipids?

Answer 33

33% (freezes less than milk)

Question 34

What % of egg fat is sterols (cholesterol)?

Answer 34

5%

Question 35

What is in trace amts. in egg fat?

Answer 35

Cerebrosides

Question 36

What 5 fatty acids are most common in eggs?

Answer 36

Myristic 1%, Palmitic 27%, Stearic 6%, Oleic 50%, Linoleic 11%

Question 37

What % of egg fatty acids are saturated?

Answer 37

34% (1/3)

Question 38

Where are carbohydrates in eggs?

Answer 38

Little in albumen

Question 39

What vitamins do eggs have?

Answer 39

All (especially B, not much of C)

Question 40

What 5 aspects do consumers like in eggs?

Answer 40

Sounds + clean shells, no blood/meat spots, no off-flavors, uniformity, a lot of firm albumen

Question 41

What 3 factors from the bird that influence egg quality?

Answer 41

Genetics Physiology (blood/meat spots) Nutrition

Question 42

At higher temps it take ____ days for yolk to flatten?

Answer 42

Less

Question 43

Egg shrinkage

Answer 43

Loss of water b/c of low humidity, air cell grows

Question 44

Liquefaction

Answer 44

1. CO2 lost to atmosphere 2. Albumen binds less H2O 3. Yolk enlarges (No microorganisms involved)

Question 45

Eggs should be stored at ____ temp and ____ humidity.

Answer 45

Low (4-12C/45-55F), high (80%+)

Question 46

Grading is based on

Answer 46

Consumer preferences

Question 47

Candling: an AA graded egg will have

Answer 47

A small air cell, faint/not visible yolk, firm albumen, no blood/meat spots, sound shell

Question 48

Candling: a B graded egg will have

Answer 48

A large air cell, visible + mobile yolk, liquid albumen, blood/meat spots, bad shell

Question 49

Breakout method: an AA graded egg will have

Answer 49

High yolk height and less spread albumen

Question 50

Color has no effect on egg quality but…

Answer 50

People like uniformity