Vitamin A Distribution Among Fat Globule Core, Fat Globule Membrane, and Serum Fraction in Milk

¹ Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108
² Department of Applied Statistics, University of Minnesota, St. Paul 55108

In cream suspensions and partly skimmed milks obtained by successive centrifugation from whole milk, the concentration of vitamin A per gram of fat was inversely related to the mean size of fat globules. This result indicated that not all the vitamin A of milk was located in the fat globule core, which was further supported by studies of buttermilk and butter oil fractions obtained by churning of cream. These studies indicated that a portion of the vitamin A was associated with the fat globule membrane. The vitamin A content per gram of fat of purified fat globules was similar to vitamin A content per gram of fat of the whole milk from which they were isolated. This result indicated that the amount of vitamin A in the serum fraction was negligible and that vitamin A was localized in the fat globule and fat globule membrane.

Key Words: vitamin A • distribution • milk

Submitted on November 17, 1993
Accepted on November 7, 1994