Food Chemistry

10.2 Dairy Products 537

Fig. 10.30.Production of casein, caseinates, and coprecipitate

at 90◦C. Joint coagulation of proteins can also
be achieved by first heat-denaturing the whey
proteins, then acidifying the milk. Washing fol-
lowed by drying of the curd gives a coprecipitate
which contains up to 96% of the total proteins of

the milk. When casein dispersions, 20–25%, are
treated with alkali [NaOH or Ca(OH) 2 ,alkalior
alkaline-earth carbonates or citrates] at 80–90◦C
and pH 6.2–6.7, and then the solubilized product
is spray-dried, a soluble or readily dispersable ca-
sein product is obtained (caseinate, disintegrated
milk protein).
Caseins and whey proteins are also concentrated
by ultrafiltration and reverse osmosis. Since the
molar masses of the whey proteins and casein mi-
celles are in the range of 10^3 –10^4 and 10^7 –10^9
respectively, membranes with a pore diameter of
5–50 nm are suitable for the separation of these
proteins.
Casein and caseinate are utilized as food and
also have nonfood uses. In food manufacturing
they are used for protein enrichment and/or to
achieve stabilization of some physical properties
of processed meats, baked products, candies, cer-
eal products, ice creams, whipping creams, coffee
whiteners, and some dietetic food products and
drugs.

The nonfood uses involve wide application of ca-

sein/caseinate as a sizing (coating) for better qual-

ity papers (for books and journals, with a surface

suitable for fine printing), in glue manufactur-

ing, as a type of waterproof glue (alkali caseinate

with calcium components as binder); in the tex-

tile industry (dye fixing, water-repellent impreg-

nations); and for casein paints and production of

some plastics (knobs, piano keyboards, etc.).

10.2.10 Whey Products

Whey accumulates in considerable amounts in the

production of cheese and casein.

The composition of whey and whey products is

presented in Table 10.36. Whey and whey prod-

ucts are used in animal feed, dietetic foods (infant

food), bread, confectionery, candies, and bever-

ages.

10.2.10.1 Whey Powder

In dairy farming, two process variants are applied

for the drying of whey: