2009_Book_FoodChemistry

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 followed
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 casein
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 micelles
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, cereal
products, ice creams, whipping creams, coffee
whiteners, and some dietetic food products and
drugs.
The nonfood uses involve wide application of casein/caseinate
as a sizing (coating) for better quality
papers (for books and journals, with a surface
suitable for fine printing), in glue manufacturing,
as a type of waterproof glue (alkali caseinate
with calcium components as binder); in the textile
industry (dye fixing, water-repellent impregnations);
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 products
are used in animal feed, dietetic foods (infant
food), bread, confectionery, candies, and beverages.
10.2.10.1 Whey Powder
In dairy farming, two process variants are applied
for the drying of whey: