1. Basic composition of the raw cow’s milk Flashcards
1
Q
Main composition:
- Water
A
88 %
2
Q
Main composition:
- Dry matter (solids)
A
12-16%
3
Q
Main composition:
- Solids non-fat
A
8,7-9%
4
Q
Main composition:
- Proteins
A
Proteins 3,3 %
Casein 2,5 %
Whey proteins0,6%
Membrane proteins of fat globules 0,02%
5
Q
Main composition:
- Fat
A
3,3-6,1%
6
Q
Main composition:
- Lactose
A
4,5-5%
7
Q
Main composition:
- Salt and minerals
A
0,6-0,8%
8
Q
Main composition:
Non-protein nitrogenous compounds e.g. urea, creatine
A
very low %
9
Q
Main composition:
Gases
A
0,012 %
10
Q
Cow milk content compared to other animals:
A
- ruminants have casein type milk
- mares do not have casein type milk, same as human’s
11
Q
Water in milk
A
- 88% of milk
- water activity = ratio of water vapour pressure to vapour pressure air saturated with water —
average is about 0,993 - free
- bound to colloids or chemically bound
- a small amount of water in milk is bound by proteins and fat globule membranes so that cannot
solve small molecules and ions i.e. non-solvent water - according of the diameter of particles dispersed in water — 3 phases:
1. emulgated stage: for fat
2. colloidal dispersion: all the proteins — casein, a-laclatlbumin, ß-lactoglobulin,
serumalbumin, proteins on the surface later of globules
3. molecular dispersion: saccharides, water soluble vitamins, non-protein non-nitrogenous compounds, gases, cations, anions
12
Q
5) Milk proteins
A
cf. question 4
13
Q
) Milk fat
A
- most variable component of milk
- 3,6-4% of the total composition of cow milk
- easily digestible
- provides:
- energy: 1g = 9 cal.
- nutrients: essential FA, fat soluble vitamins
- 2 groups:
1. homolipids: - represent esters: FA + alcohol
- main one = TAG, forms the majority of the bovine milk fat
- others DAG, MAG, sterols
2. heterolipids (compound lipids): - besides FA and alcohols, bound compounds containing N, P, S
- e.g. phospholipids, cerebrosides, sulphatides
14
Q
Factors influencing milk fat composition
A
Genetic, environmental factors,
15
Q
Fatty acids
A
- mainly saturated 70%
- unsaturated FA 30%
- monosaturated 26-42% - polyunsaturated 2-6%
16
Q
Saturated FA:
A
- most important from a quantitative viewpoint = palmitic acid (16 C), accounts for almost 30% of total FA
- other important ones: myristic (14 C) and stearic (18 C), account for 10-12% each
17
Q
Unsaturated FA:
A
- oleic acid (18 C and 1 double bond — 18:1): on second place after palmitic acid, 17-25%
- important polyunsaturated FA are 18:2 (linolic acid) and 18:3 (linolenic acid) +++
18
Q
7) Lactose
A
cf. question 2
