Dairy Chemistry And Biochemistry

214

Dissolving Vat No. 2,

vigorous agitation

DAIRY CHEMISTRY AND BIOCHEMISTRY

Heat to -75~

NnOH solution to pH -6.6

Dissolving Vat No. 1,

Recirculate andor transfer

pH measurement

I

NaOH solution, if necessary

Viscosity measurement,

hot H20, if necessary

INa caseinate powder1

Figure 4.38 Protocol for the manufacture of sodium caseinate (from Mulvihill, 1992).

usually spray dried. Caseinates form very viscous solutions and solutions
containing only about 20% casein can be prepared; this low concentration
of protein increases drying costs and leads to a low-density powder. Calcium
caseinate forms highly aggregated colloidal dispersions.
Direct acidification with HCl or in situ production of lactic acid by a
mesophilic lactic starter still dominate in the production of acid casein. A
relatively recent development in the production of acid casein is the use of
ion exchangers for acidification. In one such method, a portion of the milk
is acidified to approximately pH 2 at 10°C by treatment with a strong acid
ion exchanger and then mixed with unacidified milk in proportions so that
the mixture has a pH of 4.6. The acidified milk is then processed by
conventional techniques. A yield increase of about 3.5% is claimed, appar-
ently due to the precipitation of some proteose-peptones. The resulting
whey has a lower salt content than normal and is thus more suitable for
further processing. The elimination of strong acid reduces the risk of
corrosion by the chloride ion (Cl-) and hence cheaper equipment may be