Agriculture Reference
In-Depth Information
Table 14.4
Average composition of fatty acids (FA) in goat, cow, and human milk.
Fatty acid
1
Goat milk
Cow milk
Human milk
Saturated FA, total
2.37
2.00
1.85
C4:0 butyric
0.13 (2.6)
0.11 (3.3)
—
C6:0 caproic
0.09 (2.9)
0.06 (1.6)
—
C8:0 caprylic
0.10 (2.7)
0.04 (1.3)
—
C10:0 capric
0.26 (8.4)
0.08 (3.0)
0.06 (1.3)
C12:0 lauric
0.12 (3.3)
0.09 (3.1)
0.26 (3.1)
C14:0 myristic
0.32 (10.3)
0.34 (9.5)
0.32 (9.5)
C6 - 14:0 (MCT)
2
1.02
0.72
0.64
C16:0 palmitic
0.91 (24.6)
0.88 (26.5)
0.92 (20.2)
C18:0 stearic
0.44 (12.5)
0.40 (14.6)
0.29 (6.0)
MUFA
3
,
total
1.06
0.92
1.65
C16:1 palmitoleic
0.08 (2.2)
0.08 (2.3)
0.13 (5.7)
C18:1 oleic
0.98 (28.5)
0.84 (29.8)
1.48 (46.4)
C20:1
—
trace
0.04
C22:1
—
trace
trace
PUFA
4
,
total
0.15
0.13
0.45
C18:2 linoleic
0.11
0.08
0.37
C18:3 linolenic
0.04
0.05
0.05
C18:4
—
trace
—
C20:4
—
trace
0.03
1
(in g/100 g fat).
2
MCT = medium - chain triglycerides.
3
MUFA = monounsaturated FA.
4
PUFA = polyunsaturated FA.
Source: Posati and Orr, 1976 .
(β - Lg), and α - lactalbumin ( α - La). Instead of α
s2
- CN, the
α
s1
- casein (
from Holstein or Jersey cows (Table 14.5), which can be
important in human nutrition. The use of goat milk as a
hypoallergenic food substitute for cow milk has been
reported in often successful treatment of patients allergic
to cow milk (Walker, 1965; Park, 1994), and may be attrib-
uted to the low frequency of α
s1
-CN found in goat milk
(Moioli et al., 1998 ).
The most abundant amino acids in milk of many species
are glutamate (plus glutamine, 20%), proline (10%), and
leucine (10%). Of these three major amino acids in goat
milk, glutamate and proline are higher and leucine is lower
in human milk than goat milk. Of the sulfur-containing
amino acids, cystine is higher and methionine is lower in
human than in goat milk (Davis et al., 1994).
s2
-CN) is present in the milk of some indi-
vidual goats and breeds generally as a minor protein, while
it is the major protein in cow milk (Park, 2006). β - casein
is the major casein fraction in goat milk. The protein com-
position in goat milk is determined by genetic polymor-
phisms. Differences in amino acid composition between
casein fractions in goat milk are much greater than differ-
ences between species (goat versus cow). Casein micelles
of goat milk are less solvated, less heat stable, and lose
β-casein more readily than cow milk micelles (Juàrez and
Ramos, 1986 ).
Goat milk proteins are more digestible than those in cow
milk due to the smaller, softer, and more friable curd for-
mations of goat proteins during acidifi cation in the stomach,
providing stomach proteases easier digestive actions (Park,
2006). Nubian breed goat milk contains signifi cantly
higher levels of major buffering components, such as
proteins, nonprotein N, and phosphate (P
2
O
5
) than milk
α
Carbohydrates
The major carbohydrate in goat milk is lactose. Lactose is
a disaccharide made up of a glucose and galactose mole-
cule and is synthesized in the mammary gland. Lactose in
