Rennet from animals

Parmesan or Grana, as it is known in Italy, is a group of very hard bacteria-ripened, granular-textured cheeses made from partially skimmed cow s milk. They originated in Parma, near Emilia, Italy, hence the name. Special lipolytic enzymes derived from animals are used, in addition to rennet, to produce the characteristic rancid flavor. 

Some of the traditionally used industrial enzymes (e.g., rennet and papain) are prepared from animal and plant sources. Recent developments in industrial enzyme production have emphasized the microbial enzymes (Frost 1986). Microbial enzymes are very heat stable and have a broader pH optimum. Most of these enzymes are made by submerged cultivation of highly developed strains of microorganisms. Developments in... 

The environmental benefits are (1) cheese makers are no longer dependent upon enzymes recovered from slaughtered calves and lambs for production of rennet needed for most cheese making processes, and (2) based on current demands for chymosin, commercial needs for rennet could not be met from animal sources. The consumer benefits are (1) plentiful, consistently high quality enzyme chymosin is available at low prices that help assure availability of excellent cheeses at a reasonable cost and (2) people who follow kosher and vegetarian eating practices can consume cheese since the enzyme is from a microbe and not a calf. 

Cheese making—During this process, milk is clotted by either acid or rennet (an enzyme-containing substance derived from animal stomachs) so that it separates into cheese and whey. Usually, much more calcium and phosphorus are lost in the whey from acid-clotted items like cottage cheese than from the rennet-clotted cheeses like Cheddar and Swiss. 

Rennets. The traditional rennets used to coagulate milk for most cheese varieties are prepared from the stomachs of young calves, lambs or kids by extraction with NaCl (c. 15%) brines. The principal proteinase in such rennets is chymosin about 10% of the milk-clotting activity of calf rennet is due to pepsin. As the animal ages, the secretion of chymosin declines while that of pepsin increases in addition to pepsin, cattle appear to secrete a chymosin-like enzyme throughout life. 

Rennet or rennin—an animal prolease derived from the stomachs of calves as well as from microorganisms. Rennet is used in the manufacture of cheese to clot milk. 

Sousa, M. J. and Malcata, F. X. (1998). Identification of peptides from ovine milk cheese manufactured with animal rennet or extracts of Cynara cardunculus as coagulant. J. Agric. Food Chem. 46, 4034-4041. 

Rennet, Bovine Aqueous extracts made from the fourth stomach of bovine animals. Clear, amber to dark-brown liquid or white to tan powder. Major active principle protease (pepsin). Typical application manufacture of cheese. Similar preparations can be made from the fourth stomach of sheep or goats. 

The quantity of anti-rennet contained normally in the blood can be increased considerably by injections of rennet taken from the animal under consideration. These injections can be made under the skin, in the veins, or even in the peritoneal cavity. They are repeated at intervals of lo days approximately. After lo injections, we get the maximum formation of anti-enz)rme. Briot has treated rabbits with subcutaneous injections of Hansen s liquid rennet, which is previously freed of its salts by dialysis and then filtered through a Chamberland filter. He has found that the proportion of anti-rennet in serum increases with each injection While at the beginning, i c.c. of serum was capable of neutralizing i c.c. of rennet diluted i to 1200, after 8 injections, i c.c. of serum could neutralize i c.c. of rennet diluted only i to 50. 

These data moreover coincide with the experiments of Bang and Hammarsten, who found that there is a difference between the rennets taken from the gastric mucous membranes of man and of the hog and between rennets coming from pike and from calf. Furthermore, the active substances taken from the calf stomach lining also vary according to the age and the manner of nutrition of the animal... 

EndopepUdases (proteinoses) catalyse the hydrolysis of bonds within the peptide chain, forming variously sized cleavage peptides. They can be further subdivided into acidic, neutral and basic endopeptidases. Neutral and basic types can each be divided into Serine proteases (see) and thiol proteinases (see Thiol enzymes). Examples of animal endopeptidases are Pepsin (see). Rennet enzyme (see), Ttypsin (see), Elastase (see). Thrombin (see), Plasmin (see) and Renin (see). For examples of plant and bacterial endopeptidases, see Papain, Subtilisin, Bromelain. Endopeptidases have also been isolated from yeast and fungi. 

In addition to the edible (food) and nonfood (inedible) products, certain chemical substances useful as human drugs or pharmaceuticals are obtained as by-products. Among such drugs are ACTH, cholesterol, estrogen, epinephrine, heparin, insulin, rennet, thrombin, TSH, and thyroid extracts—all valuable pharmaceuticals which are routinely recovered from meat animals in the United States. 

Casein occurs in several animal and vegetable materials but the only source of commercial importance is cow s milk, in which the casein content is about 3%. In commercial practice, casein is isolated from skimmed milk by either acid coagulation or by rennet coagulation. In acid coagulation, dilute sulphuric acid is added to the milk at about 35°C, with stirring. Coagulation... 

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