2009_Book_FoodChemistry

3.4 Phospho- and Glycolipids 179
Table 3.18. Occurrence of phosphatidyl derivates
Food Lipid P-containing Phosphatidyl derivatives b (mg/kg)
(g/kg) lipids a (g/kg) PC
PS PE PI
Milk 37.8 0.35 120 10 100 2
Egg 113 35.1 27,000 ¾ 5810 ¾
Meat (beef) 19 8.3 4290 690 1970 ¾
Meat (chicken) 62 6.6 3320 850 1590 ¾
Tuna fish 155 19.4 6410 1940 5030 ¾
Potato 1.1 0.56 280 10 160 90
Rice 6.2 0.89 320 30 350 ¾
Soybean 183 17.8 7980 ¾ 4660 2500
a Phosphatidyl derivatives and other P-containing lipids, e. g., plasmalogens, sphingomyelins.
b The abbreviations correspond to Formulas 3.26 – 3.29.
OH-group of choline, PC):
(3.26)
Phosphatidyl serine (phosphate group esterified
with the HO-group of the amino acid serine, PS):
Examples of foods which contain phosphatidyl
derivatives are shown in Table 3.18. The differences
to the data in Table 3.17 are caused by the
biological range of variations.
Only one acyl residue is cleaved by hydrolysis
(cf. 3.7.1.2.1) with phospholipase A. This yields
the corresponding lyso-compounds from lecithin
or phosphatidyl ethanolamine. Some of these
lyso-derivatives occur in nature, e. g., in cereals.
Phosphatidyl glycerol is invariably found in green
plants, particularly in chloroplasts:
(3.27)
Phosphatidyl ethanolamine (phosphate group esterified
with ethanolamine, PE):
L-α-Phosphatidyl-D-glycerol (3.30)
(3.28)
Cardiolipin, first identified in beef heart, is also
a minor constituent of green plant lipids. Its
chemical structure is diphosphatidyl glycerol:
Phosphatidyl inositol (phosphate group esterified
with inositol, PI):
Diphosphatidyl glycerol (cardiolipin) (3.31)
(3.29)
A mixture of phosphatidyl serine and phosphatidyl
ethanolamine was once referred to as
cephalin.
The plasmalogens occupy a special place in the
class of phospho-glycerides. They are phosphatides
in which position 1 of glycerol is linked
to a straight-chain aldehyde with 16 or 18 carbons.
The linkage is an enolether type with a dou-