Milk and Eggs

Question 1

Nutrient information of Milk per Kg

Answer 1

Energy - 2.72
Protein - 34g
Carb - 48g
Fat - 37g
Water - 880g
Ca - 19mg

Question 2

Milk sturcture

Answer 2

Continuous phase
Dispersed phase
Suspension

Question 3

Continuous phase

Answer 3

Water
Sugar
Other small molecules

Question 4

Dispersed Phase

Answer 4

Lipid globules - 1-10um (emulsion)

Question 5

Suspencion

Answer 5

Protein micelles

100-250nm

Question 6

Milk Fat

Answer 6

Present as emulsified droplet in aqueous emulsion
Surrounded by lipid/protein membrane derived from cell membrane
Predominantly TAG
Melting Point 34 degrees

Question 7

Centrifugation

Answer 7

Rapid spinning remove solid particles from liquid due to density difference

Water is heavier than fat

Speed of centrifuge and flow rate of milk determines how much of the cream is removed

Holes in most disks help guide the seperation of two liquid phases

Question 8

Homogenisation of milk

Answer 8

Fat globules are forced through small opening under pressure
Globules are stretched and then broken
Fragments spontaneously reseal to form separate stable small globules

First step breaks up large globules
Second Step break of small clusters

Question 9

Whipped cream

Answer 9

Fat globules into small ones using pressure fluctuations

Question 10

Butter

Answer 10

Continued Vigorous agitation of cream makes the fat globules coalesce completely into butter

Question 11

Egg structure

Answer 11

Shell - two membrane, calcified shell and outer wax layer

Egg white - 11% protein, <0.5 fat (67% of egg without shell)

Yolk - 16% protein, 31% fat

Question 12

Egg Emulsifier

Answer 12

Most Lipid molecules are bound to protein, carbs, choline or phosphate known as lecithin

In egg yolks lipids occur mostly in membrane and in LDL

Phospho and glycolipids
Amphipathic - liquid part of molecule is hydrophobic and the other part is hydrophilic. The molecule is more stable straddling a boundary between water and liquid
At low temperature these compounds can immobilise much more liquid than already in yolk

Question 13

Mayonnaise

Answer 13

Utilises the emulsifier in egg yolk (Amphipathic molecules)

Mix equal amount of egg yolk with plant oil at low temp
Works better at a low pH
Slowly add more oil until 4 time egg yolk weight

Question 14

Processing Egg

Answer 14

Fractionation
Pasteurisation
Drying

Question 15

Fractionation of egg

Answer 15

Separate yolk and white

Question 16

Pasteurisation of egg

Answer 16

Rapid pasteurisation at specific temp and time more likely to kill pathogen

Question 17

Drying egg

Answer 17

Stabilise material for trasnport, storage, protection against oxygen, prevent oxidation of lipids

Question 18

Pasteurisation of liquid whole egg

Answer 18

64 degrees

2.5 minutes

Question 19

Pasteurisation of liquid egg yolk

Answer 19

60 degrees

3.5 minutes

Question 20

Pastuerisation of liquid egg white

Answer 20

55 degrees

9.5 minutes