Loss of Material During the Isolation of Milk Fat Globule Membrane

Cream from uncooled fresh milk was washed three times in buffered sucrose.Membrane material was recovered from the washings and skim milk by centrifugation.Almost all milk protein was removed in three washes.The amount of phospholipid recovered decreased from wash 1 to wash 3. The total loss was 4% of the original cream phospholipid.The electrophoretic pattern of the major proteins in the particulate fraction of wash 1 was similar to membrane material from skim milk while that of wash 3 was similar to total fat globule membrane.Morphologically, the particulate matter of all the washings contained the same structural elements, primarily unit membrane-bound vesicles with a dense core and fragments of membrane.The proportion of fragments increased from wash 1 to wash 3. A selective disruption of milk fat globule membrane occurs during the washing process, and at least 16% of the membrane protein is removed.