Milk constituents

KE Price, Z Zolli, Jr, JC Atkinson, HG Luther. Antibiotic inhibitors. I. The effect of certain milk constituents. Antibiot Chemother 7 672-688, 1957. 

Balannec, B., Gesan-Guiziou, G., Chaufer, B., Rabiller-Baudry, M., and Daufin, G., Treatment of dairy processing waters by membrane operations for water reuse and milk constituents concentration, Desalination,147, 89-94, 2002. 

Dorough, H.W. and G.W. Ivie. 1968. Carbon-14 milk constituents fed carbamate labelled with carbon-14 on the carbonyl. Science 159(3816) 732-733. 

The book does not cover the technology of the various dairy products, although brief manufacturing protocols for some products are included to facilitate discussion however, a number of textbooks on various aspects of dairy technology are referenced. Neither are the chemical analyses, microbiology and nutritional aspects of dairy products covered, except in a very incidental manner. The effects of dairy husbandry on the composition and properties of milk are discussed briefly, as is the biosynthesis of milk constituents in both cases, some major textbooks are referenced. 

Milk constituents are synthesized from components obtained from the blood consequently, the mammary gland has a plentiful blood supply and also an elaborate nervous system to regulate excretion. 

The substrates for milk synthesis enter the secretory cell across the basal membrane (outside), are utilized, converted and interchanged as they pass inwards through the cell and the finished milk constituents are excreted into the lumen across the lumenal or apical membrane. Myoepithelial cells (spindle shaped) form a basket around each alveolus and are capable of contracting on receiving an electrical, hormonally mediated, stimulus, thereby causing ejection of milk from the lumen into the ducts. 

Injection of radioactively labelled substrates, e.g. glucose, into the bloodstream permits assessment of the milk constituents into which that substrate is incorporated. It may also be possible to study the intermediates through which biosynthesis proceeds. 

Davies, D.T. and White, J.C.D. (1960) The use of ultrafiltration and dialysis in isolating the aqueous phase of milk and in determining the partition of milk constituents between the aqueous and disperse phases. J. Dairy Res., 27, 171-90. 

The stability of dairy products decreases sharply above a critical water activity (section 7.8). This decrease in stability is related to the influence of water on the glass transition and the role of water as a plasticizer of amorphous milk constituents (Roos, 1997). 

Thus, most enzymes enter milk due to peculiarities of the mechanism by which milk constituents, especially the fat globules, are excreted from the secretory cells. Milk does not contain substrates for many of the enzymes present, while others are inactive in milk owing to unsuitable environmental conditions, e.g. pH. 

Technological, in which an enzyme is used to modify a milk constituent or to improve its microbiological, chemical or physical stability. 

Photo-oxidation of milk constituents was discused in detail by Walstra and Jenness (1984). 

Ci8 derivatized silica as the sorbent, while a diphasic dialysis membrane procedure was employed for the isolation of chloramphenicol residues from milk constituents using ethyl acetate as the extraction solvent (68). 

Gaunt, S. N. 1980. Genetic variation in the yields and contents of milk constituents. In Factors Affecting the Yield and Contents of Milk Constituents of Commercial Importance. P. C. Moore and J. A. F. Rook (Editors). Internat. Dairy Fed. Doc. 125. 

Ahmed, A. A., McCarthy, R. D. and Porter, G. A. 1979. Effect of milk constituents on hepatic cholesterol-genesis. Atherosclerosis 32, 347-357. 

Have, A. J., van der, Deen, J. R. and Mulder, H. 1980. The composition of cow s milk. V. The contribution of some milk constituents to the freezing point depression studies with separate milkings of individual cows. Neth. Milk Dairy J. 34, 1-8. 

Whittier, E. 0. 1933A. Buffer intensities of milk and milk constituents. III. Buffer action of calcium phosphate. J. Biol. Chem. 102, 733-747. 

Mather, I. H. and Keenan, T. W. 1983. Function of endomembranes and the cell surface in the secretion of organic milk constituents. In Biochemistry of Lactation. T. B. Mepham (Editor). Elsevier/North-Holland, Amsterdam, pp. 231-283. 

Many milk constituents affect the manufacturing and various characteristics of cheese, but milk fat and casein are of primary importance since they constitute most of the solids in cheese (e.g., 91% of the solids in Cheddar cheese). These two constituents, plus water, influence the yield of cheese from milk and the gross composition of cheese (Van Slyke and Price 1952). Formulas used to predict the cheese yield from milk include the concentration factors of casein and fat in milk, a minor correction factor for other milk constituents, and the added salt and moisture content of cheese (Van Slyke and Price 1952 Lelievre et al. 1983 Banks et al. 1984). 

Kataoka, K., Nakae, T. 1973. Comparative studies of milk constituents of various mammals in Japan. VIII. Comparison in phospholipids composition of the milk from various mammals. Japan. J. Dairy Sci., 22, 137—142. 

Shennan, D.B., Peaker, M. 2000. Transport of milk constituents by the mammary gland. Physiol. Rev. 80, 925-951. 

Avoidance of interference of other milk constituents with measurements is also of importance for example, dissociation of casein micelles by calcium-chelating agents, such as trisodium citrate or ethylenediamine tetra-acetic acid (EDTA), may used to avoid interference of the micelles in particle size measurement, while clusters of fat globules can be disrupted by adding a low level of sodium dodecyl sulphate (SDS). 

Overall, it is apparent that, although fat globules are not the predominant milk constituent affecting the rheological properties of milk and cream, they still exhibit a considerable influence. 

Increased recognition of the nutritional significance of components of the MFGM has led to a number of studies dedicated to the extraction and production of MFGM from buttermilk. Specific processes have been designed to obtain MFGM isolates free from other milk constituents, with the explicit objective of their use as bioactive and functional food ingredients. The differences in composition between isolates produced from different... 

Precht, A., Peters, K.-H., Petersen, J. 1988. Improvement of storage stability and foaming properties of cream by addition of carrageenan and milk constituents. Food Hydrocoll. 2, 491-506. 

There is a possibility that some milk constituents regulate the absorption of ions in the intestine. In studying manganese metabolism we turned to the low iron content in milk. Iron has received great attention in pediatric nutrition. The concern has been to prevent the anemia caused by iron deficiency earlier often found in childhood. Wide milk consumption by infants and young children makes this food an attractive vehicle for iron fortification. Iron-enriched proprietary milk substitutes can adequately prevent the anemia common to infants who subsist largely on low-iron mother s or cow s milk (53). 

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