Food Biochemistry and Food Processing

19

Chemistry and Biochemistry

of Milk Constituents

P. F. Fox and A. L. Kelly

425

Introduction
Lactose
Introduction
Chemical and Physicochemical Properties of Lactose
Food Applications of Lactose
Lactose Derivatives
Nutritional Aspects of Lactose
Lactose in Fermented Dairy Products
Milk Lipids
Definition and Variability
Fatty Acid Profile
Conjugated Linoleic Acid
Structure of Milk Triglycerides
Rheological Properties of Milk Fat
Milk Fat as an Emulsion
Stability of Milk Fat Globules
Creaming
Homogenization of Milk
Lipid Oxidation
Fat-Soluble Vitamins
Milk Proteins
Introduction
Heterogeneity of Milk Proteins
Molecular Properties of Milk Proteins
Casein Micelles
Minor Proteins
Immunoglobulins
Bovine Serum Albumin (BSA)
Metal-Binding Proteins

2 -Microglobulin
Osteopontin
Proteose Peptone 3
Vitamin-Binding Proteins
Angiogenins
Kininogen
Glycoproteins

Proteins in the Milk Fat Globule Membrane

Growth Factors

Indigenous Milk Enzymes

Milk Salts

Vitamins

Summary

References

INTRODUCTION

Milk is a fluid secreted by female mammals, of

which there are approximately 4500 species, to meet

the complete nutritional, and some of the physiolog-

ical, requirements of the neonate of the species. Be-

cause nutritional requirements are species specific

and change as the neonate matures, it is not surpris-

ing that the composition of milk shows very large

interspecies differences; for example, the concentra-

tions of fat, protein, and lactose range from 1 to

50%, 1 to 20%, and 0 to 10%, respectively. Inter-

species differences in the concentrations of many of

the minor constituents of milk are even greater than

those of the macro constituents. The composition of

milk changes markedly during lactation, reflecting

the changing nutritional requirements of the neo-

nate. Milk composition also changes markedly dur-

ing mastitis and physiological stress. In this chapter,

the typical characteristics of the principal, and some

of the minor, constituents of bovine milk will be

described.

Sheep and goats were domesticated about 8000

BC, and their milk has been used by humans ever

since. However, cattle, especially breeds of Bos

Food Biochemistry and Food Processing

Edited by Y. H. Hui

Copyright © 2006 by Blackwell Publishing