Dairy Chemistry And Biochemistry

228

Adjust pH

DAIRY CHEMISTRY AND BIOCHEMISTRY

Skim milk

7.0-7.5 * -10

1

Heating conditions 90°C x 10-15 min

Coo t ed to 20°C

Precipitation conditions Acidify to

pH 4.6

Soluble lactoprotein

(SW

I

60°C x 3 min

Acidify to

pH4.6

Cooled to 20°C

Total milk protein

TruP)

t

NaOH

Na salts of SLP or TMP

Figure 4.44 Protocols for the manufacture of soluble lactoprotein and total milk proteins (from
Mulvihill, 1992).

ality of the caseins is not adversely affected; probably, the denatured whey
proteins do not complex with the casein micelles at the elevated pH.

4.16 Biologically active proteins and peptides in milk

Milk contains a wide range of biologically active proteins/peptides, e.g.
indigenous enzymes (perhaps 60), vitamin-binding proteins, metal-binding
proteins, immunoglobulins, various growth factors and peptide hormones.
Many of these proteins may eventually find commercial application as
isolation procedures are improved but, at present, three are of commercial
interest, viz., lactoperoxidase, lactotransferrin and immunoglobulins. In
addition, all the principal milk proteins contain sequences which when
released on proteolysis exhibit biological activity. The subject has been
reviewed by Fox and Flynn (1992).