Isolation and Identification of Casein From Milk Course Notes

Milk is the probably the most nutritionally complete food found in nature. Whole milk contains vitamins (principally thiamine,riboflavin, panthothenic acid and vitamins A, B₁₂ and D), minerals (calcium, sodium, phosphorus, potassium, and trace minerals), proteins (which include all the essential amino acids), carbohydrates (mostly lactose), and lipids (fats). Whole milk is an oil in water emulsion, containing approximately 4% fat dispersed as very small (micron sized) globules. The fat emulsion is stabilized by complex phospholipids and proteins that are absorbed on the surface of the emulsion. Since the fat in milk is so finely dispersed it is more easily digested than fats from any other source.

Isolation of Casein, Lactose, and Albumin from Milk

Milk is a food of exceptional interest. Not only is milk an excellent food for the very young, but humans

have also adapted milk, specifically cow’s milk, as a food substance for persons of all ages. Many

specialized milk products like cheese, yogurt, butter, and ice cream are staples of our diet.

Experiment 11: Isolation and Characterization of Casein from Milk

Adapted from Experiment 21, “Isolation of Protein, Carbohydrate and Fat from Milk”, in

Mohr. S.C., Griffin, S.F., and Gensler, W. J. Laboratory Manual for Fundamentals of

Organic and Biological Chemistry by John McMurry and Mary E. Castellion,: nglewood

Cliffs, Prentice-Hall, 1994 and Wayne P. Anderson (4/2002)

ISOLATION OF CASEIN FROM MILK

Purpose: In this lab you will be isolating the proteins casein and lactalbumin from a sample of milk. You

will use these values to determine the percent protein in milk compared to the listed value on the box.