Eggs Flashcards
(100 cards)
1
Q
Best way to distinguish freshness of egg
A
Seeing if egg sinks of floats is best way
2
Q
What happens to the egg as it ages?
A
Air increases in size and can migrate to the side of the egg
3
Q
What is the best way of keeping eggs fresh?
A
Store in carton not door so less air introduced into the cell
4
Q
Albumin
A
Thick and thin components of albumin
5
Q
What is obvious when you crack a fresh egg open onto a plate?
A
Thick albumin is obvious thick and tall as it surrounds the egg
6
Q
Colour of the shell and nutrition
A
Colour of shell is no impact on nutrition value of the egg, just due to breed of the hen that lays the egg
7
Q
White egg hens
A
Leg Horn Hens
8
Q
Brown egg hens
A
Rhode Island Red Hens
9
Q
Colour of yolk
A
Varies with feed of the hen, but doesn’t indicate nutritive content
10
Q
What is the yolk a major source of?
A
Vitamins, minerals, and fat
11
Q
What is a chalazae?
A
Twisted cordlike strands of egg white
12
Q
What does the chalazae do?
A
Anchor yolk in center of the egg
13
Q
What does the prominent chalazae of the egg indicate?
A
Prominent chalazae indicates freshness
14
Q
What is the air pocket of the egg
A
Pocket of air formed at large end of egg
15
Q
What is the air cell caused by?
A
Contraction of the contents during cooling after laying
16
Q
What are the two membranes of the shell?
A
Inner and outer shell membranes surround the albumen
17
Q
Where does the air cell form?
A
Between these two membranes
18
Q
Where is the thin albumen?
A
Nearest to the shell and spreads around thick white of high quality eff
19
Q
Colour of thin albumen?
A
White
20
Q
Colour of thick albumen
A
White
21
Q
What is thick albumen a source of?
A
Major source of egg riboflavin and protein. Stands higher and spreads less than thin white in high-grade eggs
22
Q
When do thins become indistinguishable?
A
In lower grade eggs
23
Q
What are differences in nutrition composition of the eggs related to?
A
The diet of the hens
24
Q
Where does pale colours of the yolk comes from?
A
Hans that are provided a wheat diet
25
When is the yolk more intense?
If the diet predominant in corn
26
When is yolk more orange in colour?
Carotenoids and betacarotene or fortifying feed with carotene
27
PH of egg yolk
pH of yolk is 6- 6.2
28
PH of egg white
on the alkaline side of the pH scale. Egg white tends to be 7.6 - 7.9
29
What happens when the chalazae becomes weakened?
The yolk then can shift its position and is no longer centered and can more towards one of the sides. You will notice that when you hard boil eggs
30
Size of the egg from start of laying cycle to end end
The size of the egg changes from the start to the end of laying cycle from a small egg to an extra large or jumbo egg
31
The larger the egg what happens to the shell
The larger the egg has a greater tendency for weakness in the shell
32
Why may jumbo or extra large eggs be lower quality?
Jumbos or extra large may have lower quality due to being more fragile
33
Why is the health of eggs important?
Need to ensure that there is control in lighting, temperature, water availability, and maintaining a clean environmental.
34
Process of egg production
Egg production farm
Egg collection process
Egg pickup from producer
Washing eggs
Candling eggs
Weighing and sizing eggs
Egg packaging
35
Washing eggs
Making sure they’re clean and no fecal material
36
What is candling eggs?
Using candlelight to image the interior structures. Air shell, chalazae, position of the yolk
Focuses on quality of egg
37
Egg packaging
Strength of calcium that makes up the egg shell means that you can push from end to end with force and it will not break. Allows us to stack them on top of one another
38
What is the grey ring around hard cooked egg yolk?
Ferrous sulfied that gives eggs the grey colour
39
What is present in yolk vs white contain?
Iron in yolk and hydrogen sulfide in white
40
What does hydrogen sulfide do?
will diffuse from egg white to surface of yolk where it will interact with the iron of the yolk and when H2S interacts with the iron of the yolk this si where you get ferrous sulfide
41
What is the grey rings in eggs more obvious in?
more stale eggs. Especially when you cool them slowly instead of rapidly
42
Where are eggs sold by the producer?
To a grading station for sorting according to size and grade
43
What does mass of egg determine?
Size
44
What does size of egg include?
Includes the shell of the egg which is different from the nutrition value.
45
What sized eggs can be grade A?
Possible for any egg sizes to be designated Grade A
46
What do egg grades depend on?
A,B, C
Position of yolk
Size of air cell
Quality of shell
47
What do egg grades depend on?
A,B, C
Position of yolk
Size of air cell
Quality of shell
48
Position of yolk
Centered and anchored by chalazae
49
Size of air cell
Small and centered at wide end
50
Quality of shell
Strong and thick
51
How long does it take from the egg to go from the hen to retail?
Typically takes 5 to 7
52
Distribution of eggs: Retail sales
55.1%
53
Distribution of eggs: hotels, restaurants, and institutions
27.6%
54
Distribution of eggs: Industrial Processors
17.3%
55
Industrial processors
turned into dried eggs for cake mix, egg whites, egg bites etc
56
Egg white proteins
Ovalbumin
Ovotransferrin
Ovomucoid
Ovomucin
57
Ovalbumin egg white composition
54%
58
Type of protein is ovalbumin
Simple protein (polypeptide chain on its own)
59
Ovalbumin solubility
Water solubility
60
Structure of ovalbumin
Solid gel and opaque
61
What does heat do for ovalbumin ?
denatured with formation of solid water holding gel that is opaque in nature
62
Percent of ovotransferrin in eggs
12%
63
What does ovotransferrin bind?
Bind Fe 2+/3+
64
Ovotransferrin where does it come into play?
iron interactions in yolk and white and that is where ovotransferrin comes into play and it capable of interacting with Fe 2+ or 3+
65
Percent that ovomucoid makes up?
11%
66
What kind of protein is ovomucoid?
Glycoprotein
67
What is ovomucoid subject to?
Subject to post translational modification
With one sugar added on to the peptide chain
68
Percent of ovomucin?
3.5%
69
Characteristics of ovomucin
Glycoprotein and filamentous
70
Where is ovomucin present?
in thick albumin at a 4x greater concentration than in the thin albumin
71
What does ovomucin allow?
Allows thick albumin to stand up and be distinct
72
Ph as eggs age
pH change due to carbon dioxide.
Part of thick albumin being less obvious is change in ovomucin as a result of the change in pH
73
Proteins in egg yolk
Lipoproteins
74
What do lipoproteins contains in their structure?
Phospholipids within their structure and phospholipids are stabilizers
75
Cell membrane of lipoproteins
cell membrane structure with the hydrophilic head and hydrophobic tail
76
What does the structure of lipoproteins make them?
An emulsifier
77
Lipoproteins lecithin
The generic term by phosphotidal choline is more scientific name
78
What does cooking with eggs center around?
Centres around coagulation of egg proteins
79
Temperature of cooking egg whites
62- 65 degrees C
80
Tempature of cooking egg yolds
65-70 degrees C
81
Temperature denatures for eggs
Whites and yolks differ
82
What makes the difference in cooking temperature?
Yolk has significant proportion of lipid which makes a different in temperature of coagulation and denaturation
83
Dilution
Increase in temperature for denaturation
84
What will dilution increase?
The temperature for denaturation/coagulation to occur
85
Direct heatings vs indirect heating and denaturation
Direct heat will cause the proteins to denature a lot quicker opposed to the water bath for custard which allow proteins to unfold more slowly and binding moisture in the thickening or coagulation process
86
Methods of egg agitation with cooking
Slow and uniform coagulation (liquid, soft stirred custard)
87
Liquid vs gel form of eggs
Liquid when agitates and gel when not agitated
88
What process if responsible for the thickened consistency of stirred custard?
Unfolding proteins, exposing the different regions of the polypeptides chains. If they polypeptide regions are hydrophilic you can see how they can easily bind the moisture which would be responsible for the thickened consistency of the stirred custard
89
What is formed in the absence of agitation?
Production of a moisture biding gel (semi-solid) product
90
What affect will sugar have on egg?
Protective effect on proteins requiring greater temperatures for proteins to denature
91
Effect of salt on egg?
Salt charged ions can actually enhance denaturation of proteins by virtue of their charges they can interact with amino acid residues of protein (side chains) and encourage the denaturation of the protein mixture. Minor or small effect because you don’t add a lot of salt to most of your products.
92
Soft custard process
Talking about indirect method of heating, the presence of sugar will increase temperature required for denaturation because of its hydrophilic nature and capacity to bind water it causes proteins to denature at higher temperature. We want to have a soft liquid or loose texture to soft custards and need constant stirring to prevent gel formation. Just thickened but do not want a gel in the soft custard. Key proteins that give us thickening are egg proteins (mostly egg white but also egg yolk) thicken by unfolding and binding water
93
Baked custard process
Coagulation going from a sol (water soluble native state of proteins in egg and milk mixure) converted into a semi solid moisture holding gel. order to get the gel you cannot stir or agitation the product. It needs to sit in the water bath undisturbed
94
When does curdling happens
Curdling happens with extensive and prolonged heating of our mixtures.
95
What is curdling the result of?
Overdenaturation of proteins so they no longer bind moisture
96
Characteristics of curdling
Clumps of protein have separated from the aqueous environment. Clear separation of denatures protein from aqueous surroundings.
97
Proteins interact with what in coagulation
Proteins interact with each other not water so they precipitate or fall out of solution.
98
What temperature do changes in thickening happen?
Changes in thickening as the temperature gets over 70 C. We will see thickening and coagulation around this time
99
Degrees of safety for flow heating vs branding up heat quickly
Slow heating gives five degrees of safety but quickly brining up heat bring 3 degrees of sagety. 5 vs 3 is difference between coagulation and curdling
100
What is the key to baked custard?
??? **** listen to video****
Even coagulation from constant stirring which will give you a thickened fluid custard and zero agitation is key to baked custard because the slow denaturation due to the water bath allows proteins to slowly unfold and form a network with the water
