Heat-induced changes in milk

In modern dairy technology, milk is almost always subjected to a heat treatment typical examples are  

LTLT (low temperature, long time) HTST (high temperature, short time) Forewarming (for sterilization) 

Of the principal constituents, the lipids are probably the least affected by heat. However, significant changes do occur in milk lipids, especially in their physical properties, during heating. 

Heating per se to above 70°C denatures membrane proteins, with the exposure and activation of various amino acid residues, especially cysteine. 

Severe heat treatment, as is encountered during roller drying and to a lesser extent spray drying, results in at least some demulsification of milk fat, with the formation of free fat, which causes (Chapter 3)  

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Andrews, G. (1989) Lactulose in heated milk, in Heat-Induced Changes in Milk, (ed. P.F. Fox), Bulletin 238, International Dairy Federation, Brussels, pp. 45-52. 

Fox, P. F. 1981A. Heat-induced changes in milk preceding coagulation. J. Dairy Sci. 64, 2127-2137. 

Driessen, F.M. 1989. Heat-induced changes in milk. Bulletin 238, International Dairy Federation, Brussels. 

Holt, C. (1995). Effect of heating and cooling on the milk salts and their interaction with casen. In "Heat-Induced Changes in Milk" (P.F. Fox, ed.), pp. 105-133. International Dairy Federation, Brussels. 

Other hand, are relatively heat labile, being completely denatured by heating at 90°C for 10 min. Heat-induced changes in milk are discussed in Chapter 9. 

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