The serum remaining after removal of the solids (fat and casein) from milk. Dried whey contains about 13% protein, 71% lactose, 2.3% lactic acid, 4.5% water, and 8% ash, including a low concentration of phosphoric anhydride. Besides its value as an inexpensive source of protein for animal feeds, whey is used as a source of lactose and lactic acid, as well as for the synthesis of riboflavin, acetone, butanol, and fuel-grade ethanol by fermentation processes. Some types of cheese are made from whey, and it is also a possible culture medium. Dried whey may be used to replace up to 75% of the polyol component of rigid polyurethane foams.
Whey is the portion of milk remaining after coagulation and removal
of curd. there are two principal types: sweet whey obtained during
the making of rennet-type hard cheeses like cheddar and swiss,
with a ph of approximately 6.1; and acid whey obtained during the
making of acid-type cheeses such as cottage cheese, with a ph of
approximately 4.4–4.6. whey is used as a source of lactose, milk
solids, and whey proteins. it is used in baked goods, ice cream, and
dry mixes.
