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Milk Composition & Synthesis
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Milk Synthesis
Milk Fat

Milk Fat Composition

Milk fat is composed primarily of triglycerides (or triacylglycerides) are 98% of the total milk fat (by weight). Other milk lipids (as a percentage of the total milk fat) include: diacylglycerides (0.25-0.48%); monoacylglycerides (0.02-0.04%); phospholipids (0.6-1.0%); cholesterol (0.2-0.4%); glycolipids (0.006%); and free fatty acids in milk (0.1-0.4%).

The fatty acid composition of milk varies substantially among mammalian species, as indicated by the table below.

Fatty Acid Composition in Milk From Several Species

Fatty Acid

Rabbit
Guinea pig
Mouse
Rat
Sow
Cow
Sheep
Goat
        Molar Percent      
Short Chain                
C4:0
<1
<1
<1
<1
*
11
8
8
C6:0
<1
<1
<1
<1
*
5
5
5
C8:0
37
<1
<1
6
*
1
4
4
Medium Chain                
C10:0
27
<1
7
17
*
3
6
13
C12:0
3
<1
12
13
*
3
5
7
C14:0
1
2
16
13
2
10
10
12
Long Chain                
C16:0
8
34
33
28
28
23
22
24
C18:0
2
3
2
3
6
10
10
12
C18:1
9
31
14
13
35
29
22
17
C18:2
10
23
8
7
14
2
4
3
C18:3
1
4
<1
<1
<1
<1
<1
<1

*For the sow, the sum of C4:0 to C12:0 is 2% total.

Common fatty acids:

C16:0 palmitate or palmitic acid
C18:0 sterate or steric acid
C18:1 oleate or oleic acid
C18:2 linolate or linoleic acid, an essential FA
C18:3 linolenate or linolenic acid, an essential FA

For more on Milk Fat and Milk Fat Synthesis see: Davies et al., 1983, Ch. 3 in Biochemistry of Lactation, Mepham TB ed., p. 71; Dils, 1983, Ch. 5 in Biochemistry of Lactation, Mepham TB ed., p. 141; Jensen et al., 1991, J. Dairy Sci. 74:3228; Mather IH, Keenan TW 1998 Origin and secretion of milk lipids. J. Mammary Gland Biology and Neoplasia 3:259-274.
Milk Fat
Milk Composition & Synthesis
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