Animal rennet comes from baby calves.
Before 1990, the majority of cheese manufacturers used animal rennet in dairy processing. The stomach enzymes chemically convert milk into cheese curds. Today, biologically engineered enzymes, safe for vegetarian consumption, often replace traditional stomach-derived rennet in dairy manufacturing. Some cheeses, including high-quality gorgonzola and grana padano, continue to contain animal rennet.
Features
The fourth chamber of a juvenile ruminant's stomach contains rennet. Animal rennet includes rennin, a milk-clotting enzyme, according to the U.S. Food and Drug Administration. Processors extract the rennin, also known as chymosin, from the stomach of new born calves for use in dairy production. After being slaughtered, the calves stomachs are removed so rennin extraction can begin. After washing and drying the stomachs, the flesh soaks for up to five days in a boric acid and brine mixture to release the rennin. The liquid mixture is then refined to collect the rennin.
Uses
Rennet added to milk and soft cheese during processing aids in coagulation. For example, in the production of genuine hard Parmesan cheese, production requires cow's milk, calf rennet and salt. Some cheese types do not require rennet. Although dairy production is the primary use for rennet, the pharmaceutical industry also uses the enzymes in the production of drugs, according to the United States Department of Agriculture.
Effects
During cheese manufacturing, when animal rennet combines with milk, curds and liquid whey form. The small amount of rennin used to curdle milk poses no health risks to babies or adults, according to the FDA.
Types
Cheese makers use liquid, paste and powdered forms of animal rennet. Coloring, preservatives and additional proteins added to animal rennet sold for home cheese-making use makes the product more stable. Makers of provolone, feta and Romano cheese prefer to use paste-style animal rennet.
History
Long ago, milk stored in bags made from young goat, calf or sheep stomachs gave rise to the discovery of animal rennet, according to David B. Fankhauser, Ph.D., Professor of Biology and Chemistry at the University of Cincinnati Clermont College. After a day of storage in the stomach bag, the milk curdled leaving behind small milk solids and liquid. The solid chunks of milk were separated out, dried and salted for later consumption.
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