The composition of milk fat.
Bovine milk contains about 3.5 to 5% total lipid, existing as emulsified globules 2 to 4 microns in diameter and coated with a membrane derived from the secreting cell. In homogenized milk, the coat is mostly casein. About 98% or more of the lipid is triacylglycerol, which is found in the globule. Phospholipids are about .5 to 1% of total lipids, and sterols are .2 to .5%. These are mostly located in the globule membrane. Cholesterol is the major sterol at 10 to 20 mg/dl. Data are presented on the membrane and the emulsion. Bovine milk contains substantial quantities of C4:0 to C10:0, about 2% each of C18:2 and trans-C18:1, and almost no other long-chain polyunsaturated fatty acids. The fatty acid composition is not altered by ordinary changes in diet. The triacylglycerol structure is unique, with much of the C4:0 to C10:0 at sn-3. The effects of milk cholesterol and fatty acids on human blood cholesterol levels and nonnutritive roles of some microlipids are discussed.
Jensen
R G
RG
Department of Nutritional Sciences, University of Connecticut, Storrs 06269-4017.
Ferris
A M
AM
Lammi-Keefe
C J
CJ
D000818:Animals; D002417:Cattle; D002784:Cholesterol / Q000032:analysis; D004655:Emulsions; D005227:Fatty Acids / Q000032:analysis; D008055:Lipids / Q000737:chemistry*; D008892:Milk / Q000032:analysis*; D010743:Phospholipids / Q000032:analysis; D013261:Sterols / Q000032:analysis; D014280:Triglycerides / Q000032:analysis
D004655:Emulsions; D005227:Fatty Acids; D008055:Lipids; D010743:Phospholipids; D013261:Sterols; D014280:Triglycerides; D002784:Cholesterol